12,000 miles and 5 controllers later

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12,000 miles and 5 controllers later

Tom H
After three years and 12,000 miles on my converted pick-up, I would like to share some of my experiences with the discussion list.  Maybe something I say here will help someone just starting to avoid some of the mistakes I have made.  

Sizing the controller –
One of the benefits touted for electric motors is that they can give you maximum torque right from the beginning as low rpms.  However, none of the books on EV conversions (or other information) make it clear that the relationship between controller, motor, and battery pack is much more complicated.  I need about 32 hp (24 Kwatts) of power to go up the hills on my commute.  This means that the motor would be drawing about 200 amps from my 120 volt battery pack – quite reasonable for flooded lead acid batteries.  So a controller rated at 400 amps maximum should be OK, right? WRONG!  What no one told me was that at low rpms the motor voltage is much lower.  I have an Impulse 9 motor and have measured that at 2000 rpm it only is running at 44 volts.  This means that the controller has to be putting out 545 amps to get the necessary power (32 hp).

This was my first mistake.  I purchased a Curtis 1221 controller rated at 400 amps.  I had real trouble starting up hills at lights because I did not have enough current to the motor at the low rpms to get the power I needed even though the controller was putting out the 400 amps.  At 2000 rpm I was getting only 23 hp (about 17 Kwatts) to the motor.  When starting, the power was even less.  So I was very glad I kept my manual transmission.  It allowed me to drive around with the Curtis, albeit at a slow speed.  I was able to get a high enough rpm in first gear to get enough power to the motor to get going.  
My suggestions: The rating of a controller should be about 3-4 times higher than your expected current from the  battery pack when going up hills or starting.  I needed 200 amps from my battery pack.  I found that a controller rated at 600 amps (Kelly) was just barely adequate at one at 700 amps (Logisystems) and 800 amps (Kelly) did the job.  I now have a Net Gain rated at 1000 amps and that works the best.  If you decide for a direct drive and eliminate the transmission you will probably need to double that rating.  

Five controllers blow up –
I replaced the underpowered Curtis with a Kelly KDH12600B (600 amp controller).  This was adequate but blew out while driving after about 3 months.  The folks at Kelly replaced it without any charge and let me upgrade to a KDH12800B (800 amp).  Unfortunately this one lasted only one month and blew out.  The folks at Kelly replaced it with another 12800B.  This one lasted only 1 week before blowing up.  So, the folks at Kelly replaced it with a KDH14650B.  This one ran OK but I was reluctant to use it for very long.  So, I purchased a Logisystems 700 amp controller.  This one lasted for 1 year before blowing up.  Logisystems repaired it under warranty but the repair only lasted four months before blowing up again.  
Warning..when these controller blow while driving it can be a harrowing experience.  There is a big bang and everything dies.  You just hope there is a place you can pull over before the car stops.  
So why did all of these controllers keep blowing up on me?  Either I have bad “karma” with  EV’s or there is something in my system that is causing failure of the capacitors.  All I have been able to find out is that the electrolytic capacitors used in these controllers have weak points.  The gearing or driving style may cause duty cycle to hover around certain values that can maximize ripple currents the capacitors must handle, and therefore work them to death.  Anyone have other ideas?

Where am I now?—
After the Logisystems controller blew up the second time I decided to purchase a NetGain controller rated at 1000 amps.  The newer version of the NetGain controller and the Soliton controller both use thin-film capacitors rather than electrolytic ones.  These are supposed to be less prone to problems.  We shall see.  The NetGain controller however was only two thirds the price of Soliton so I went with that one.  I have had the NetGain installed and running for five months now without blowing up, and it is providing me with more than enough power. I also purchased the computer module (called the Interface Module) that allows me to monitor over a dozen different factors and alter controller defaults.  Five of the most important variables (current to motor, voltage at motor, current from battery pack, voltage at battery pack, controller temperature) are all on one screen so I don’t need five dials.  It also stores the data on a disk that I can download to a spreadsheet. This is really cool!

However, the NetGain has not been without a problem.  I would call this more “teething” problem since it involved the internal software (called firmware) rather than the hardware.  Nothing as drastic as getting stranded on the side of the road.   When I first installed the NetGain I would get sudden power drops I can best describe as “hiccups.”  The folks at NetGain figured out that it was a result of a communications snafu between two circuits in the controller caused by electrical noise from the high current wires.  I guess I do have bad “karma” for EVs.  This noise problem had not shown up in all of the previous controllers they sold.  I sent the controller back to NetGain for a firmware fix and that solved the problem.  [I also got their latest version of the mother board in the process that further reduced the footprint of the controller by 1 inch.]

So now, finally, I have a controller that has the power I need and hopefully will not blow up on me.  I should also mention an additional benefit of the NetGain controller. It uses a Hall effect throttle rather than pot box and has a much better response when starting up.  All of the previous controllers caused a sudden “jump” in the car when I stepped on the throttle.  The Logisystems was the worst.  The NetGain however is very smooth and does not do this.

Tom H.
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Re: 12,000 miles and 5 controllers later

Roland Wiench
Hello Tom,

That seems to be a lot of motor ampere for your EV.  Everyday I run up a
steep 1 mile hill between speeds of 10 to 35 mph and can keep the motor
ampere at or about 200 amps at 60 volts while the battery is at 75 amps at
180 volt.

How do I do it?  Back in 85 I replace the differential gear ratio from a
2.78:1 to a 5.57:1.  The transmission 1st gear ratio is a 3.5:1 giving me a
overall ratio of 3.5 x 5.57 = 19.495:1.

The maximum mph in this first gear ratio is about 6000 rpm at 25 mph, but I
do not take it up to 6000 rpm.  I shift into 2nd when the motor gets to
about 1800 rpm or 10 mph.  The motor ampere is at 200 ampere at this rpm and
gear ratio.

Shifting into 2nd the maximum mph is 35 mph at 6000 rpm, but again I only
take it to 1800 rpm in 2nd gear which is about 25 mph where again the motor
ampere is at 200 amperes.

Shifting into 3rd the maximum mph is 90 mph at 6000 rpm, but I only take it
to 1800 rpm which is about 35 mph which again the motor ampere is at 200
amperes.

Why 1800 rpm?  Because for A WarP 11 motor, this is where the maximum HP at
the maximum torque is develop in this motor which is call the sweet spot of
a motor. This size motor is ideal for driving at these speeds in city.

A WarP 9 motor has it maximum HP and maximum torque at 3300 rpm which should
be 200 motor amperes at 50 mph with a 5.57:1 overall gear ratio.

Note - This data is sent to me in a spreadsheet for my EV from NetGain.

To calculate your MPH per RPM:


                           RPM  X  Tire Circumference in Inches
                  MPH =    ------------------------------------
                           Overall Gear Ratio  x  1056

Roland




----- Original Message -----
From: "Tom H" <[hidden email]>
To: <[hidden email]>
Sent: Friday, May 27, 2011 12:46 PM
Subject: [EVDL] 12,000 miles and 5 controllers later


> After three years and 12,000 miles on my converted pick-up, I would like
> to
> share some of my experiences with the discussion list.  Maybe something I
> say here will help someone just starting to avoid some of the mistakes I
> have made.
>
> Sizing the controller –
> One of the benefits touted for electric motors is that they can give you
> maximum torque right from the beginning as low rpms.  However, none of the
> books on EV conversions (or other information) make it clear that the
> relationship between controller, motor, and battery pack is much more
> complicated.  I need about 32 hp (24 Kwatts) of power to go up the hills
> on
> my commute.  This means that the motor would be drawing about 200 amps
> from
> my 120 volt battery pack – quite reasonable for flooded lead acid
> batteries.
> So a controller rated at 400 amps maximum should be OK, right? WRONG!
> What
> no one told me was that at low rpms the motor voltage is much lower.  I
> have
> an Impulse 9 motor and have measured that at 2000 rpm it only is running
> at
> 44 volts.  This means that the controller has to be putting out 545 amps
> to
> get the necessary power (32 hp).
>
> This was my first mistake.  I purchased a Curtis 1221 controller rated at
> 400 amps.  I had real trouble starting up hills at lights because I did
> not
> have enough current to the motor at the low rpms to get the power I needed
> even though the controller was putting out the 400 amps.  At 2000 rpm I
> was
> getting only 23 hp (about 17 Kwatts) to the motor.  When starting, the
> power
> was even less.  So I was very glad I kept my manual transmission.  It
> allowed me to drive around with the Curtis, albeit at a slow speed.  I was
> able to get a high enough rpm in first gear to get enough power to the
> motor
> to get going.
> My suggestions: The rating of a controller should be about 3-4 times
> higher
> than your expected current from the  battery pack when going up hills or
> starting.  I needed 200 amps from my battery pack.  I found that a
> controller rated at 600 amps (Kelly) was just barely adequate at one at
> 700
> amps (Logisystems) and 800 amps (Kelly) did the job.  I now have a Net
> Gain
> rated at 1000 amps and that works the best.  If you decide for a direct
> drive and eliminate the transmission you will probably need to double that
> rating.
>
> Five controllers blow up –
> I replaced the underpowered Curtis with a Kelly KDH12600B (600 amp
> controller).  This was adequate but blew out while driving after about 3
> months.  The folks at Kelly replaced it without any charge and let me
> upgrade to a KDH12800B (800 amp).  Unfortunately this one lasted only one
> month and blew out.  The folks at Kelly replaced it with another 12800B.
> This one lasted only 1 week before blowing up.  So, the folks at Kelly
> replaced it with a KDH14650B.  This one ran OK but I was reluctant to use
> it
> for very long.  So, I purchased a Logisystems 700 amp controller.  This
> one
> lasted for 1 year before blowing up.  Logisystems repaired it under
> warranty
> but the repair only lasted four months before blowing up again.
> Warning..when these controller blow while driving it can be a harrowing
> experience.  There is a big bang and everything dies.  You just hope there
> is a place you can pull over before the car stops.
> So why did all of these controllers keep blowing up on me?  Either I have
> bad “karma” with  EV’s or there is something in my system that is causing
> failure of the capacitors.  All I have been able to find out is that the
> electrolytic capacitors used in these controllers have weak points.  The
> gearing or driving style may cause duty cycle to hover around certain
> values
> that can maximize ripple currents the capacitors must handle, and
> therefore
> work them to death.  Anyone have other ideas?
>
> Where am I now?—
> After the Logisystems controller blew up the second time I decided to
> purchase a NetGain controller rated at 1000 amps.  The newer version of
> the
> NetGain controller and the Soliton controller both use thin-film
> capacitors
> rather than electrolytic ones.  These are supposed to be less prone to
> problems.  We shall see.  The NetGain controller however was only two
> thirds
> the price of Soliton so I went with that one.  I have had the NetGain
> installed and running for five months now without blowing up, and it is
> providing me with more than enough power. I also purchased the computer
> module (called the Interface Module) that allows me to monitor over a
> dozen
> different factors and alter controller defaults.  Five of the most
> important
> variables (current to motor, voltage at motor, current from battery pack,
> voltage at battery pack, controller temperature) are all on one screen so
> I
> don’t need five dials.  It also stores the data on a disk that I can
> download to a spreadsheet. This is really cool!
>
> However, the NetGain has not been without a problem.  I would call this
> more
> “teething” problem since it involved the internal software (called
> firmware)
> rather than the hardware.  Nothing as drastic as getting stranded on the
> side of the road.   When I first installed the NetGain I would get sudden
> power drops I can best describe as “hiccups.”  The folks at NetGain
> figured
> out that it was a result of a communications snafu between two circuits in
> the controller caused by electrical noise from the high current wires.  I
> guess I do have bad “karma” for EVs.  This noise problem had not shown up
> in
> all of the previous controllers they sold.  I sent the controller back to
> NetGain for a firmware fix and that solved the problem.  [I also got their
> latest version of the mother board in the process that further reduced the
> footprint of the controller by 1 inch.]
>
> So now, finally, I have a controller that has the power I need and
> hopefully
> will not blow up on me.  I should also mention an additional benefit of
> the
> NetGain controller. It uses a Hall effect throttle rather than pot box and
> has a much better response when starting up.  All of the previous
> controllers caused a sudden “jump” in the car when I stepped on the
> throttle.  The Logisystems was the worst.  The NetGain however is very
> smooth and does not do this.
>
> Tom H.
>
>
> --
> View this message in context:
> http://electric-vehicle-discussion-list.413529.n4.nabble.com/12-000-miles-and-5-controllers-later-tp3556075p3556075.html
> Sent from the Electric Vehicle Discussion List mailing list archive at
> Nabble.com.
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
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Re: 12,000 miles and 5 controllers later

Tom H
Hi Roland,
It looks like you need a lot less power to run up your hills.  If your battery pack is putting out 75 amps at 180 volts you are using only 13.5 Kilowatts of power.  To get up some of the hills around here in Olympia Wa I need about 24 kilowatts of power to the motor.  Especially if I am starting up hill at a stop light.

My Nissan pickup with me in it weighs in at 4000 lbs.  (I have 1400 lbs of batteries - 20 6 volt golf cart)

So you power needs are much less than mine.  That will definitely change the equations. I did not change the gear ratios because that was a little beyond my engineering skills for the conversion.  

Tom
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Re: 12,000 miles and 5 controllers later

SLPinfo.org
In reply to this post by Roland Wiench
Roland (and/or anyone else who might be able to assist),

You have mentioned this "sweet spot" before.  I have tried to find it for my
ADC 9", but have not been successful.  I have found torque curves (several
at this site)
http://www.evparts.com/products/street-vehicle/motors--dot/96-to-192-volt-street-vehicle-motors/mt2120.htm
,
but I'm not an engineer and I don't know how to read them.  I've tried
contacting Advanced DC, but they basically ignore my emails.
Any idea what the sweet spot might be for my motor?       I run a 120V
system.

btw - since it's such a commonly used motor, this info might help others
too.

Thanks in advance.

- Peter Flipsen Jr



On Fri, May 27, 2011 at 2:11 PM, Roland Wiench <[hidden email]> wrote:

> Hello Tom,
>
> That seems to be a lot of motor ampere for your EV.  Everyday I run up a
> steep 1 mile hill between speeds of 10 to 35 mph and can keep the motor
> ampere at or about 200 amps at 60 volts while the battery is at 75 amps at
> 180 volt.
>
> How do I do it?  Back in 85 I replace the differential gear ratio from a
> 2.78:1 to a 5.57:1.  The transmission 1st gear ratio is a 3.5:1 giving me a
> overall ratio of 3.5 x 5.57 = 19.495:1.
>
> The maximum mph in this first gear ratio is about 6000 rpm at 25 mph, but I
> do not take it up to 6000 rpm.  I shift into 2nd when the motor gets to
> about 1800 rpm or 10 mph.  The motor ampere is at 200 ampere at this rpm
> and
> gear ratio.
>
> Shifting into 2nd the maximum mph is 35 mph at 6000 rpm, but again I only
> take it to 1800 rpm in 2nd gear which is about 25 mph where again the motor
> ampere is at 200 amperes.
>
> Shifting into 3rd the maximum mph is 90 mph at 6000 rpm, but I only take it
> to 1800 rpm which is about 35 mph which again the motor ampere is at 200
> amperes.
>
> Why 1800 rpm?  Because for A WarP 11 motor, this is where the maximum HP at
> the maximum torque is develop in this motor which is call the sweet spot of
> a motor. This size motor is ideal for driving at these speeds in city.
>
> A WarP 9 motor has it maximum HP and maximum torque at 3300 rpm which
> should
> be 200 motor amperes at 50 mph with a 5.57:1 overall gear ratio.
>
> Note - This data is sent to me in a spreadsheet for my EV from NetGain.
>
> To calculate your MPH per RPM:
>
>
>                           RPM  X  Tire Circumference in Inches
>                  MPH =    ------------------------------------
>                           Overall Gear Ratio  x  1056
>
> Roland
>
>
>
>
> ----- Original Message -----
> From: "Tom H" <[hidden email]>
> To: <[hidden email]>
> Sent: Friday, May 27, 2011 12:46 PM
> Subject: [EVDL] 12,000 miles and 5 controllers later
>
>
> > After three years and 12,000 miles on my converted pick-up, I would like
> > to
> > share some of my experiences with the discussion list.  Maybe something I
> > say here will help someone just starting to avoid some of the mistakes I
> > have made.
> >
> > Sizing the controller –
> > One of the benefits touted for electric motors is that they can give you
> > maximum torque right from the beginning as low rpms.  However, none of
> the
> > books on EV conversions (or other information) make it clear that the
> > relationship between controller, motor, and battery pack is much more
> > complicated.  I need about 32 hp (24 Kwatts) of power to go up the hills
> > on
> > my commute.  This means that the motor would be drawing about 200 amps
> > from
> > my 120 volt battery pack – quite reasonable for flooded lead acid
> > batteries.
> > So a controller rated at 400 amps maximum should be OK, right? WRONG!
> > What
> > no one told me was that at low rpms the motor voltage is much lower.  I
> > have
> > an Impulse 9 motor and have measured that at 2000 rpm it only is running
> > at
> > 44 volts.  This means that the controller has to be putting out 545 amps
> > to
> > get the necessary power (32 hp).
> >
> > This was my first mistake.  I purchased a Curtis 1221 controller rated at
> > 400 amps.  I had real trouble starting up hills at lights because I did
> > not
> > have enough current to the motor at the low rpms to get the power I
> needed
> > even though the controller was putting out the 400 amps.  At 2000 rpm I
> > was
> > getting only 23 hp (about 17 Kwatts) to the motor.  When starting, the
> > power
> > was even less.  So I was very glad I kept my manual transmission.  It
> > allowed me to drive around with the Curtis, albeit at a slow speed.  I
> was
> > able to get a high enough rpm in first gear to get enough power to the
> > motor
> > to get going.
> > My suggestions: The rating of a controller should be about 3-4 times
> > higher
> > than your expected current from the  battery pack when going up hills or
> > starting.  I needed 200 amps from my battery pack.  I found that a
> > controller rated at 600 amps (Kelly) was just barely adequate at one at
> > 700
> > amps (Logisystems) and 800 amps (Kelly) did the job.  I now have a Net
> > Gain
> > rated at 1000 amps and that works the best.  If you decide for a direct
> > drive and eliminate the transmission you will probably need to double
> that
> > rating.
> >
> > Five controllers blow up –
> > I replaced the underpowered Curtis with a Kelly KDH12600B (600 amp
> > controller).  This was adequate but blew out while driving after about 3
> > months.  The folks at Kelly replaced it without any charge and let me
> > upgrade to a KDH12800B (800 amp).  Unfortunately this one lasted only one
> > month and blew out.  The folks at Kelly replaced it with another 12800B.
> > This one lasted only 1 week before blowing up.  So, the folks at Kelly
> > replaced it with a KDH14650B.  This one ran OK but I was reluctant to use
> > it
> > for very long.  So, I purchased a Logisystems 700 amp controller.  This
> > one
> > lasted for 1 year before blowing up.  Logisystems repaired it under
> > warranty
> > but the repair only lasted four months before blowing up again.
> > Warning..when these controller blow while driving it can be a harrowing
> > experience.  There is a big bang and everything dies.  You just hope
> there
> > is a place you can pull over before the car stops.
> > So why did all of these controllers keep blowing up on me?  Either I have
> > bad “karma” with  EV’s or there is something in my system that is causing
> > failure of the capacitors.  All I have been able to find out is that the
> > electrolytic capacitors used in these controllers have weak points.  The
> > gearing or driving style may cause duty cycle to hover around certain
> > values
> > that can maximize ripple currents the capacitors must handle, and
> > therefore
> > work them to death.  Anyone have other ideas?
> >
> > Where am I now?—
> > After the Logisystems controller blew up the second time I decided to
> > purchase a NetGain controller rated at 1000 amps.  The newer version of
> > the
> > NetGain controller and the Soliton controller both use thin-film
> > capacitors
> > rather than electrolytic ones.  These are supposed to be less prone to
> > problems.  We shall see.  The NetGain controller however was only two
> > thirds
> > the price of Soliton so I went with that one.  I have had the NetGain
> > installed and running for five months now without blowing up, and it is
> > providing me with more than enough power. I also purchased the computer
> > module (called the Interface Module) that allows me to monitor over a
> > dozen
> > different factors and alter controller defaults.  Five of the most
> > important
> > variables (current to motor, voltage at motor, current from battery pack,
> > voltage at battery pack, controller temperature) are all on one screen so
> > I
> > don’t need five dials.  It also stores the data on a disk that I can
> > download to a spreadsheet. This is really cool!
> >
> > However, the NetGain has not been without a problem.  I would call this
> > more
> > “teething” problem since it involved the internal software (called
> > firmware)
> > rather than the hardware.  Nothing as drastic as getting stranded on the
> > side of the road.   When I first installed the NetGain I would get sudden
> > power drops I can best describe as “hiccups.”  The folks at NetGain
> > figured
> > out that it was a result of a communications snafu between two circuits
> in
> > the controller caused by electrical noise from the high current wires.  I
> > guess I do have bad “karma” for EVs.  This noise problem had not shown up
> > in
> > all of the previous controllers they sold.  I sent the controller back to
> > NetGain for a firmware fix and that solved the problem.  [I also got
> their
> > latest version of the mother board in the process that further reduced
> the
> > footprint of the controller by 1 inch.]
> >
> > So now, finally, I have a controller that has the power I need and
> > hopefully
> > will not blow up on me.  I should also mention an additional benefit of
> > the
> > NetGain controller. It uses a Hall effect throttle rather than pot box
> and
> > has a much better response when starting up.  All of the previous
> > controllers caused a sudden “jump” in the car when I stepped on the
> > throttle.  The Logisystems was the worst.  The NetGain however is very
> > smooth and does not do this.
> >
> > Tom H.
> >
> >
> > --
> > View this message in context:
> >
> http://electric-vehicle-discussion-list.413529.n4.nabble.com/12-000-miles-and-5-controllers-later-tp3556075p3556075.html
> > Sent from the Electric Vehicle Discussion List mailing list archive at
> > Nabble.com.
> >
> > _______________________________________________
> > | Moratorium on drag racing discussion is in effect.
> > | Please take those discussions elsewhere.  Thanks.
> > |
> > | REPLYING: address your message to [hidden email] only.
> > | Multiple-address or CCed messages may be rejected.
> > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > | OTHER HELP: http://evdl.org/help/
> > | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>
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|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
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| OTHER HELP: http://evdl.org/help/
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Re: 12,000 miles and 5 controllers later

Roland Wiench
In reply to this post by Tom H
I did some calculations using a relation between my EV which weighs 7000 lbs
at 13.5 kw using a 5.57:1 ratio  as to yours at 4000 lbs at 24 kw.

By weight:

(13.5 x 7000)/24 = 3935 lbs which is close enough to 4000 lbs


By differential gear ratio:

   (5.57 x 4000)/7000 = 3.18:1 at 180 volts

    Your EV at 120 volts:

   (180 x 3.18)/120 = 4.77:1 differential gear ratio

Look up the ring and pinion gear set for your vehicle at jegs.com.
to see what the closes gear ratio that will be to 4.77:1.  You can talk to
the tech there to see which will work.

This gear change will decrease your motor and battery ampere.  I have
another car that is the same and style as the EV I have.  It use to have a
2.78:1 differential gear in it and got only 13 mpg city stop and go driving
and 17 mpg highway.  Replace the gear to a 3.90:1 and it increase it by 5
mpg.

Roland








----- Original Message -----
From: "Tom H" <[hidden email]>
To: <[hidden email]>
Sent: Friday, May 27, 2011 2:47 PM
Subject: Re: [EVDL] 12,000 miles and 5 controllers later


> Hi Roland,
> It looks like you need a lot less power to run up your hills.  If your
> battery pack is putting out 75 amps at 180 volts you are using only 13.5
> Kilowatts of power.  To get up some of the hills around here in Olympia Wa
> I
> need about 24 kilowatts of power to the motor.  Especially if I am
> starting
> up hill at a stop light.
>
> My Nissan pickup with me in it weighs in at 4000 lbs.  (I have 1400 lbs of
> batteries - 20 6 volt golf cart)
>
> So you power needs are much less than mine.  That will definitely change
> the
> equations. I did not change the gear ratios because that was a little
> beyond
> my engineering skills for the conversion.
>
> Tom
>
> --
> View this message in context:
> http://electric-vehicle-discussion-list.413529.n4.nabble.com/12-000-miles-and-5-controllers-later-tp3556075p3556339.html
> Sent from the Electric Vehicle Discussion List mailing list archive at
> Nabble.com.
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
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Re: 12,000 miles and 5 controllers later

Roland Wiench
In reply to this post by Tom H
Hello Peter,

I remember back, that someone said the ADC 9 motor sweet spot is between
3500 to 3900 rpm which is about 65% of the maximum rating of that motor.

The WarP 9 motor is about in a range of 3300 to 3500 rpm.  You could contact
George F. Hamstra at NetGain.  You give him your EV data, as to type of
motors, battery data, transmission gear ratios, differential gear ratio,
controller type, size and type of tires, frontal area and weight of vehicle.
He may email you a spread sheet on what type of motors and best gear set up.

Roland




----- Original Message -----
From: "SLPinfo.org" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Friday, May 27, 2011 2:52 PM
Subject: Re: [EVDL] 12,000 miles and 5 controllers later


Roland (and/or anyone else who might be able to assist),

You have mentioned this "sweet spot" before.  I have tried to find it for my
ADC 9", but have not been successful.  I have found torque curves (several
at this site)
http://www.evparts.com/products/street-vehicle/motors--dot/96-to-192-volt-street-vehicle-motors/mt2120.htm
,
but I'm not an engineer and I don't know how to read them.  I've tried
contacting Advanced DC, but they basically ignore my emails.
Any idea what the sweet spot might be for my motor?       I run a 120V
system.

btw - since it's such a commonly used motor, this info might help others
too.

Thanks in advance.

- Peter Flipsen Jr



On Fri, May 27, 2011 at 2:11 PM, Roland Wiench <[hidden email]> wrote:

> Hello Tom,
>
> That seems to be a lot of motor ampere for your EV.  Everyday I run up a
> steep 1 mile hill between speeds of 10 to 35 mph and can keep the motor
> ampere at or about 200 amps at 60 volts while the battery is at 75 amps at
> 180 volt.
>
> How do I do it?  Back in 85 I replace the differential gear ratio from a
> 2.78:1 to a 5.57:1.  The transmission 1st gear ratio is a 3.5:1 giving me
> a
> overall ratio of 3.5 x 5.57 = 19.495:1.
>
> The maximum mph in this first gear ratio is about 6000 rpm at 25 mph, but
> I
> do not take it up to 6000 rpm.  I shift into 2nd when the motor gets to
> about 1800 rpm or 10 mph.  The motor ampere is at 200 ampere at this rpm
> and
> gear ratio.
>
> Shifting into 2nd the maximum mph is 35 mph at 6000 rpm, but again I only
> take it to 1800 rpm in 2nd gear which is about 25 mph where again the
> motor
> ampere is at 200 amperes.
>
> Shifting into 3rd the maximum mph is 90 mph at 6000 rpm, but I only take
> it
> to 1800 rpm which is about 35 mph which again the motor ampere is at 200
> amperes.
>
> Why 1800 rpm?  Because for A WarP 11 motor, this is where the maximum HP
> at
> the maximum torque is develop in this motor which is call the sweet spot
> of
> a motor. This size motor is ideal for driving at these speeds in city.
>
> A WarP 9 motor has it maximum HP and maximum torque at 3300 rpm which
> should
> be 200 motor amperes at 50 mph with a 5.57:1 overall gear ratio.
>
> Note - This data is sent to me in a spreadsheet for my EV from NetGain.
>
> To calculate your MPH per RPM:
>
>
>                           RPM  X  Tire Circumference in Inches
>                  MPH =    ------------------------------------
>                           Overall Gear Ratio  x  1056
>
> Roland
>
>
>
>
> ----- Original Message -----
> From: "Tom H" <[hidden email]>
> To: <[hidden email]>
> Sent: Friday, May 27, 2011 12:46 PM
> Subject: [EVDL] 12,000 miles and 5 controllers later
>
>
> > After three years and 12,000 miles on my converted pick-up, I would like
> > to
> > share some of my experiences with the discussion list.  Maybe something
> > I
> > say here will help someone just starting to avoid some of the mistakes I
> > have made.
> >
> > Sizing the controller –
> > One of the benefits touted for electric motors is that they can give you
> > maximum torque right from the beginning as low rpms.  However, none of
> the
> > books on EV conversions (or other information) make it clear that the
> > relationship between controller, motor, and battery pack is much more
> > complicated.  I need about 32 hp (24 Kwatts) of power to go up the hills
> > on
> > my commute.  This means that the motor would be drawing about 200 amps
> > from
> > my 120 volt battery pack – quite reasonable for flooded lead acid
> > batteries.
> > So a controller rated at 400 amps maximum should be OK, right? WRONG!
> > What
> > no one told me was that at low rpms the motor voltage is much lower.  I
> > have
> > an Impulse 9 motor and have measured that at 2000 rpm it only is running
> > at
> > 44 volts.  This means that the controller has to be putting out 545 amps
> > to
> > get the necessary power (32 hp).
> >
> > This was my first mistake.  I purchased a Curtis 1221 controller rated
> > at
> > 400 amps.  I had real trouble starting up hills at lights because I did
> > not
> > have enough current to the motor at the low rpms to get the power I
> needed
> > even though the controller was putting out the 400 amps.  At 2000 rpm I
> > was
> > getting only 23 hp (about 17 Kwatts) to the motor.  When starting, the
> > power
> > was even less.  So I was very glad I kept my manual transmission.  It
> > allowed me to drive around with the Curtis, albeit at a slow speed.  I
> was
> > able to get a high enough rpm in first gear to get enough power to the
> > motor
> > to get going.
> > My suggestions: The rating of a controller should be about 3-4 times
> > higher
> > than your expected current from the  battery pack when going up hills or
> > starting.  I needed 200 amps from my battery pack.  I found that a
> > controller rated at 600 amps (Kelly) was just barely adequate at one at
> > 700
> > amps (Logisystems) and 800 amps (Kelly) did the job.  I now have a Net
> > Gain
> > rated at 1000 amps and that works the best.  If you decide for a direct
> > drive and eliminate the transmission you will probably need to double
> that
> > rating.
> >
> > Five controllers blow up –
> > I replaced the underpowered Curtis with a Kelly KDH12600B (600 amp
> > controller).  This was adequate but blew out while driving after about 3
> > months.  The folks at Kelly replaced it without any charge and let me
> > upgrade to a KDH12800B (800 amp).  Unfortunately this one lasted only
> > one
> > month and blew out.  The folks at Kelly replaced it with another 12800B.
> > This one lasted only 1 week before blowing up.  So, the folks at Kelly
> > replaced it with a KDH14650B.  This one ran OK but I was reluctant to
> > use
> > it
> > for very long.  So, I purchased a Logisystems 700 amp controller.  This
> > one
> > lasted for 1 year before blowing up.  Logisystems repaired it under
> > warranty
> > but the repair only lasted four months before blowing up again.
> > Warning..when these controller blow while driving it can be a harrowing
> > experience.  There is a big bang and everything dies.  You just hope
> there
> > is a place you can pull over before the car stops.
> > So why did all of these controllers keep blowing up on me?  Either I
> > have
> > bad “karma” with  EV’s or there is something in my system that is
> > causing
> > failure of the capacitors.  All I have been able to find out is that the
> > electrolytic capacitors used in these controllers have weak points.  The
> > gearing or driving style may cause duty cycle to hover around certain
> > values
> > that can maximize ripple currents the capacitors must handle, and
> > therefore
> > work them to death.  Anyone have other ideas?
> >
> > Where am I now?—
> > After the Logisystems controller blew up the second time I decided to
> > purchase a NetGain controller rated at 1000 amps.  The newer version of
> > the
> > NetGain controller and the Soliton controller both use thin-film
> > capacitors
> > rather than electrolytic ones.  These are supposed to be less prone to
> > problems.  We shall see.  The NetGain controller however was only two
> > thirds
> > the price of Soliton so I went with that one.  I have had the NetGain
> > installed and running for five months now without blowing up, and it is
> > providing me with more than enough power. I also purchased the computer
> > module (called the Interface Module) that allows me to monitor over a
> > dozen
> > different factors and alter controller defaults.  Five of the most
> > important
> > variables (current to motor, voltage at motor, current from battery
> > pack,
> > voltage at battery pack, controller temperature) are all on one screen
> > so
> > I
> > don’t need five dials.  It also stores the data on a disk that I can
> > download to a spreadsheet. This is really cool!
> >
> > However, the NetGain has not been without a problem.  I would call this
> > more
> > “teething” problem since it involved the internal software (called
> > firmware)
> > rather than the hardware.  Nothing as drastic as getting stranded on the
> > side of the road.   When I first installed the NetGain I would get
> > sudden
> > power drops I can best describe as “hiccups.”  The folks at NetGain
> > figured
> > out that it was a result of a communications snafu between two circuits
> in
> > the controller caused by electrical noise from the high current wires.
> > I
> > guess I do have bad “karma” for EVs.  This noise problem had not shown
> > up
> > in
> > all of the previous controllers they sold.  I sent the controller back
> > to
> > NetGain for a firmware fix and that solved the problem.  [I also got
> their
> > latest version of the mother board in the process that further reduced
> the
> > footprint of the controller by 1 inch.]
> >
> > So now, finally, I have a controller that has the power I need and
> > hopefully
> > will not blow up on me.  I should also mention an additional benefit of
> > the
> > NetGain controller. It uses a Hall effect throttle rather than pot box
> and
> > has a much better response when starting up.  All of the previous
> > controllers caused a sudden “jump” in the car when I stepped on the
> > throttle.  The Logisystems was the worst.  The NetGain however is very
> > smooth and does not do this.
> >
> > Tom H.
> >
> >
> > --
> > View this message in context:
> >
> http://electric-vehicle-discussion-list.413529.n4.nabble.com/12-000-miles-and-5-controllers-later-tp3556075p3556075.html
> > Sent from the Electric Vehicle Discussion List mailing list archive at
> > Nabble.com.
> >
> > _______________________________________________
> > | Moratorium on drag racing discussion is in effect.
> > | Please take those discussions elsewhere.  Thanks.
> > |
> > | REPLYING: address your message to [hidden email] only.
> > | Multiple-address or CCed messages may be rejected.
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> >
>
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Re: 12,000 miles and 5 controllers later

Roger Stockton
In reply to this post by SLPinfo.org
SLPinfo.org wrote:

> You have mentioned this "sweet spot" before.  I have tried to find it for
> my ADC 9", but have not been successful.  I have found torque curves
> (several at this site)
> http://www.evparts.com/products/street-vehicle/motors--dot/96-to-192-volt-
> street-vehicle-motors/mt2120.htm,
> but I'm not an engineer and I don't know how to read them.  I've tried
> contacting Advanced DC, but they basically ignore my emails.
> Any idea what the sweet spot might be for my motor?       I run a 120V
> system.

I'm not sure what Roland means; what he wrote doesn't make much sense if taken literally:

> > Why 1800 rpm?  Because for A WarP 11 motor, this is where the maximum HP
> > at the maximum torque is develop in this motor which is call the sweet
> > spot of a motor.

For a series motor, torque is a function of current, not of RPM.  Both the ADC 9" and Warp11 (<http://www.go-ev.com/images/003_20_WarP_11_Graph.jpg>) performance curves are plotted as functions of torque, and you will notice that there is a line labelled "Amps" or "Amperes" that is nearly a straight line increasing with increasing torque.  What this tells us is that putting more current through the motor results in more torque, or loading the motor more heavily (increasing the load torque) causes it to draw more current.

Maximum torque for either motor will occur whenever the motor controller that feeds it is in current limit.

Notice that the performance curves also include a line labelled "HP", and that this line increases with increasing torque, but tends to increase more slowly at higher levels of torque.  This is because HP is proportional to the product of torque and RPM, and as the load on the motor (torque) increases, the motor slows down (RPM drops).

This is where the other lines on the performance graphs come in.  You'll notice the line labelled "RPM" and that at low values of torque (left side of the plot), it rises very rapidly.  As the load increases, the motor speed drops; it drops fairly rapidly as the torque increases from light values to moderate levels, then drops more slowly as torque continues to increase.

The RPM line tells you how fast the motor will spin, when the specified voltage is applied to it, and a given torque load is placed on the motor.  The key here is that the RPM that the motor will hold at a given load depends on how much voltage you apply to the motor; more voltage means higher speed (and more power) at the same load (torque, and therefore current).  This is why the ADC plots include a (solid) line for the measured behaviour at 75V and additional dashed RPM lines showing the behaviour when 96V or 120V is applied to the motor.

I think that what Roland is saying is that he operates his motor so that it doesn't require more than 200A of motor current, because that is what the motor is rated to handle continuously.  200A through his Warp11 results in about 40lb-ft of torque.  Following the 40lb-ft line up to the RPM line and then reading off the RPM at 40lb-ft yields about 2350RPM, but this is with 72V at the motor.  Roland notes that he gets about 1800RPM at 60V and 200A.

Notice there is one more curve on the performance graphs that we haven't mentioned yet, the one labelled "Eff" or "Eff %".  This line shows how the efficiency of the motor varies with load (torque).  Notice that it falls off rapidly at light load, and falls off relatively slowly at increasing load.  I normally think of "sweet spot" referring to operating the motor near the peak of this efficiency curve.

In the case of Roland's Warp11, notice that the peak efficiency occurs at about 60lb-ft of torque and just under 2000RPM.  Perhaps this is where Roland's 1800RPM value comes from?  However, bear in mind that there is only one efficiency line plotted, and it is for the case of 72V applied to the motor.  The shape of this line, and the location of the peak efficiency will vary somewhat with applied voltage.

So, I think that if you were to follow Roland's example with your motor, the thing to take away is that you should try to not operate you motor at higher than its rated current except perhaps briefly (if you are concerned with motor longevity).  Unless you are fortunate enough to have a pack that allows you to drive for more than 1hr continuously, you can observe the 1hr rating for your motor.  According to the EV Parts page, this is 20.8kW @ 120V, which is about 173A.

>From the ADC 9" fan cooled performance curves, 175A corresponds to about 25lb-ft of torque.  At 3200RPM, this requires 75V at the motor; at about 4000RPM, it requires 96V, and at 5200RPM it requires 120V.  At 75V and 175A (motor current), the motor would spin about 3200RPM and develop about 15HP.  It isn't quite at the peak efficiency, but it is close.

It appears that you could load it down to about 45lb-ft (260A or so) and 2400RPM (still feeding it 75V) without sacrificing much efficiency, and would get just over 20HP.  That is, the "sweet spot" is really fairly broad ;^>

Most of us don't monitor motor voltage and current, but rather battery voltage and current.  So, if you want to try to operate your motor in its sweet spot efficiency-wise, try driving in different gears at a fixed speed and see which gear allows you to hold that speed with the least battery current.  Battery voltage will vary somewhat with current, but as long as the current change isn't dramatic you can consider it effectively constant through the test and take the lowest battery current as indicating the most efficient operating point for that speed.  If you have a tach, you can note the motor speed and the battery voltage and current for the gear that lets you hold the speed with the lowest battery current.  Voltage x current = power; unless you are really lugging the motor or really winding it out, the motor efficiency will be somewhere in the 80-90% ballpark; multiply the battery power by 0.8-0.85 to estimate the mechanical power.  HP = watts / 746.  From the mechanica!
 l HP estimate, compute the torque = (HP x 5252)/RPM.

Locate this torque value (ft-lbs) on the performance chart and find where it intersects the "amps" line.  If the current corresponding to this torque is higher than you want to operate your motor at for extended periods, then you'll need to use a lower gear to increase the motor RPM at this vehicle speed, and so reduce the amount of torque (and motor current) required, even though doing so may slightly increase the battery current (due to slightly lower overall efficiency of the motor, controller, and drivetrain at that operating point).

Or, you might just follow the rule of thumb that your motor will be near peak efficiency when operated around 3000-4000RPM, and that at any given vehicle speed the motor current will be lowest when the motor is spinning fastest.

Hope this helps,

Roger.


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Re: 12,000 miles and 5 controllers later

David Sharpe
In reply to this post by Tom H
I wonder if there is something wrong with your motor. The controllers should
be self protecting. See if you have a short in the armature or less likely
the field winding. This can be done by setting up a video camera to look at
the commutator (remove the screen around the commutator) & go for a drive.
See if there is much sparking. You may also have an excessively advanced
brush timing. I blew my reconditioned Raptor 1200A after only 60 miles. I
dont think it is motor related though. The manual for the Raptor refers to a
"wild ride" if you get a blown controller. My EV took off like a 911 Porsche
with squealing wheels,  clutch until the Mosfets burnt out. Lucky not to hit
any body /things. David Sharpe

--------------------------------------------------
From: "Tom H" <[hidden email]>
Sent: Saturday, May 28, 2011 4:46 AM
To: <[hidden email]>
Subject: [EVDL] 12,000 miles and 5 controllers later

> After three years and 12,000 miles on my converted pick-up, I would like
> to
> share some of my experiences with the discussion list.  Maybe something I
> say here will help someone just starting to avoid some of the mistakes I
> have made.
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>

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Re: 12,000 miles and 5 controllers later

Jeff Major
In reply to this post by Tom H


--- On Fri, 5/27/11, Tom H <[hidden email]> wrote:
> After three years and 12,000 miles on
> my converted pick-up, I would like to
> share some of my experiences with the discussion
> list.  Maybe something I
> say here will help someone just starting to avoid some of
> the mistakes I have made. 
 
Hi Tom,

Thanks for sharing.  In a nut shell, I think you should have used a Warp9 motor, good controller and (maybe) a lower rear end ratio from the start.  As far as a sweet spot for running any DC series motor, when using a shifting transmission, you should have instruments to indicate motor current and/or RPM so you can select an appropriate gear which keeps the motor current at, near or below its one hour rating once the acceleration has ended.  This will also benefit the controller :-)

Regards,

Jeff M

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Re: 12,000 miles and 5 controllers later

Dan Baker
On 5/28/11, Jeff Major <[hidden email]> wrote:

>
>
> --- On Fri, 5/27/11, Tom H <[hidden email]> wrote:
>> After three years and 12,000 miles on
>> my converted pick-up, I would like to
>> share some of my experiences with the discussion
>> list.  Maybe something I
>> say here will help someone just starting to avoid some of
>> the mistakes I have made.
>
> Hi Tom,
>
> Thanks for sharing.  In a nut shell, I think you should have used a Warp9
> motor, good controller and (maybe) a lower rear end ratio from the start.
> As far as a sweet spot for running any DC series motor, when using a
> shifting transmission, you should have instruments to indicate motor current
> and/or RPM so you can select an appropriate gear which keeps the motor
> current at, near or below its one hour rating once the acceleration has
> ended.  This will also benefit the controller :-)
>
> Regards,
>
> Jeff M
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
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>

--
Sent from my mobile device

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Re: 12,000 miles and 5 controllers later

SLPinfo.org
In reply to this post by Roger Stockton
Roger,
First let me say that I really and truly do appreciate you taking the time
to compose your detailed response to me about Roland's "sweet spot". I
respect that your time is valuable and that you give of it freely.
However, such detailed explanations usually result in my eyes glazing over
and me mumbling to myself "what's the bottom line". I don't often read all
the long messages that show up sometimes beyond the first paragraph for that
reason. My EV is basic transportation to me - it's not a hobby. I just want
it to work efficiently. I don't have the time or the mental energy to work
through what for me are highly complex electrical, mechanical, or
engineering details. I realize that for many on this list those details are
inherently interesting but for me they are not. But I don't want anyone to
quit posting such messages for that reason. I can hit the delete button just
as easily as anyone else and I don't have a problem doing so.
Another point is that although I have a tach it doesn't work. Despite many,
many attempts using many different suggestions from the EV list I've never
been able to get it to work. I'm in the process of having my EV components
transferred from one vehicle to another, but I am not going to bother having
the tach installed. Notice that I said "having it installed". I can do some
really basic stuff on my EV, but I'm not an engineer or a mechanic so I have
to pay someone else to do it.
Roland's notion of a sweet spot was interesting to me because in waiting to
get my newer EV (97 S-10 instead of a 91 Plymouth Colt) I'm trying to figure
out optimum speeds for driving in each gear and shifting. I have formulae
for computing speeds from both Roland's posts and Mike Brown's Convert it
book, but the key number I've always been missing is RPM. No one has ever
told me what's the "optimum" rpm or the "maximum" rpm or the "shift point"
rpm that I should be aiming for. Without a tach I have to use my speedometer
(and yes my amp guage which I use to measure motor amps, not battery amps).
But the speedometer is most important because I want to avoid tickets and I
find that if I spend too much time staring at guages I'm not paying
attention to traffic like I should be. As basic transportation 90% of my EV
driving is done during rush hour.
It is interesting that Roland said 3600-3900 rpm would be the sweet spot
form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I had
never seen either of these sets of numbers before, so I have in fact learned
pretty much what I need to know. Bottom line - even though I couldn't follow
allow the details, YES your response was very helpful!
- Peter Flipsen Jr

On Fri, May 27, 2011 at 5:15 PM, Roger Stockton <[hidden email]>wrote:

> SLPinfo.org wrote:
>
> > You have mentioned this "sweet spot" before.  I have tried to find it for
> > my ADC 9", but have not been successful.  I have found torque curves
> > (several at this site)
> >
> http://www.evparts.com/products/street-vehicle/motors--dot/96-to-192-volt-
> > street-vehicle-motors/mt2120.htm,
> > but I'm not an engineer and I don't know how to read them.  I've tried
> > contacting Advanced DC, but they basically ignore my emails.
> > Any idea what the sweet spot might be for my motor?       I run a 120V
> > system.
>
> I'm not sure what Roland means; what he wrote doesn't make much sense if
> taken literally:
>
> > > Why 1800 rpm?  Because for A WarP 11 motor, this is where the maximum
> HP
> > > at the maximum torque is develop in this motor which is call the sweet
> > > spot of a motor.
>
>
> Or, you might just follow the rule of thumb that your motor will be near
> peak efficiency when operated around 3000-4000RPM, and that at any given
> vehicle speed the motor current will be lowest when the motor is spinning
> fastest.
>
> Hope this helps,
>
> Roger.
>
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>
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| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
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Re: 12,000 miles and 5 controllers later

Roland Wiench
In reply to this post by Tom H
Hello Peter,

The sweet spot data is what I received from NetGain for a 9 and 11 inch
motor.

You can convert the speedometer to a rpm indicator using the following
knowns:

Find the running circumference of the tire.  It is known that the same type
and diameter tire at the same air pressure will have a different running
circumference on different vehicles at different weight and speeds.

I learn about this way back in the 50's when I was doing road rallies where
you may drive a vehicles for 39.5 mph for 18.5 miles and then turn left.  If
there is no road to the left to turn on, then your calculations are off.

After the EV is built and the tires are air up to the pressure, but not
exceeding the max psi air pressure at maximum load that is on the side of
the tire, then you can find the running circumference.

On a smooth dried road surface, put a mark on the tire and on the road.
Move the vehicle so the tire makes one turn until that tire mark is next to
the road surface again.  Then measure the distance between the two marks on
the road.

Lets say its 85 inches which we call TC.

Now we have to find the overall gear ratio in each gear.  This is easier
with a electric motor then with a engine.  While the motor and transmission
is in the vehicle and the tires are off the ground, put a mark on the tire,
so you can keep track of one turn of the tire.

If the motor has a input shaft on the front of the motor, then you can use
the keyway position to keep track how many turns it takes for the motor
turns while the tire turns one time.

If the motor does not have a input shaft, then remove the brush cover and
put a piece of tape on the communtator to keep track of the number of
rotations.

Now shift the transmission into 1st gear and rotate the tire by hand counter
clock wise which would be the forward direction.  If you rotate the tire one
turn and the motor goes 10 turns, then your overall gear ratio is 10:1 in
1st gear.

Now shift the transmission into 2nd gear and repeat the operation.

We then now know the two known, the tire running circumference or TC
and the overall gear ratios in each transmission gears or OR.

We now converter the MPH formula to a RPM formula:

                   MPH x OR x 1056
           RPM =   ----------------
                         TC

Now calculated the RPM for each 5 mph for increase of speed as for example
in first gear at 5 mph with a overall gear ratio of 10:1 and a tire
circumference of 85 inches becomes:


                    5 mph x 10 OA  x 1056
             RPM =  ---------------------  = 621 rpm
                            85 in.


At 621 rpm, the speedo will read 5 mph in first gear.

I then find the maximum mph indication at the maximum rated motor rpm and
the mph for the sweet spot rpm.

Roland



----- Original Message -----
From: "SLPinfo.org" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Sunday, May 29, 2011 6:41 AM
Subject: Re: [EVDL] 12,000 miles and 5 controllers later


> Roger,
> First let me say that I really and truly do appreciate you taking the time
> to compose your detailed response to me about Roland's "sweet spot". I
> respect that your time is valuable and that you give of it freely.
> However, such detailed explanations usually result in my eyes glazing over
> and me mumbling to myself "what's the bottom line". I don't often read all
> the long messages that show up sometimes beyond the first paragraph for
> that
> reason. My EV is basic transportation to me - it's not a hobby. I just
> want
> it to work efficiently. I don't have the time or the mental energy to work
> through what for me are highly complex electrical, mechanical, or
> engineering details. I realize that for many on this list those details
> are
> inherently interesting but for me they are not. But I don't want anyone to
> quit posting such messages for that reason. I can hit the delete button
> just
> as easily as anyone else and I don't have a problem doing so.
> Another point is that although I have a tach it doesn't work. Despite
> many,
> many attempts using many different suggestions from the EV list I've never
> been able to get it to work. I'm in the process of having my EV components
> transferred from one vehicle to another, but I am not going to bother
> having
> the tach installed. Notice that I said "having it installed". I can do
> some
> really basic stuff on my EV, but I'm not an engineer or a mechanic so I
> have
> to pay someone else to do it.
> Roland's notion of a sweet spot was interesting to me because in waiting
> to
> get my newer EV (97 S-10 instead of a 91 Plymouth Colt) I'm trying to
> figure
> out optimum speeds for driving in each gear and shifting. I have formulae
> for computing speeds from both Roland's posts and Mike Brown's Convert it
> book, but the key number I've always been missing is RPM. No one has ever
> told me what's the "optimum" rpm or the "maximum" rpm or the "shift point"
> rpm that I should be aiming for. Without a tach I have to use my
> speedometer
> (and yes my amp guage which I use to measure motor amps, not battery
> amps).
> But the speedometer is most important because I want to avoid tickets and
> I
> find that if I spend too much time staring at guages I'm not paying
> attention to traffic like I should be. As basic transportation 90% of my
> EV
> driving is done during rush hour.
> It is interesting that Roland said 3600-3900 rpm would be the sweet spot
> form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I had
> never seen either of these sets of numbers before, so I have in fact
> learned
> pretty much what I need to know. Bottom line - even though I couldn't
> follow
> allow the details, YES your response was very helpful!
> - Peter Flipsen Jr
>
> On Fri, May 27, 2011 at 5:15 PM, Roger Stockton
> <[hidden email]>wrote:
>
> > SLPinfo.org wrote:
> >
> > > You have mentioned this "sweet spot" before.  I have tried to find it
> > > for
> > > my ADC 9", but have not been successful.  I have found torque curves
> > > (several at this site)
> > >
> > http://www.evparts.com/products/street-vehicle/motors--dot/96-to-192-volt-
> > > street-vehicle-motors/mt2120.htm,
> > > but I'm not an engineer and I don't know how to read them.  I've tried
> > > contacting Advanced DC, but they basically ignore my emails.
> > > Any idea what the sweet spot might be for my motor?       I run a 120V
> > > system.
> >
> > I'm not sure what Roland means; what he wrote doesn't make much sense if
> > taken literally:
> >
> > > > Why 1800 rpm?  Because for A WarP 11 motor, this is where the
> > > > maximum
> > HP
> > > > at the maximum torque is develop in this motor which is call the
> > > > sweet
> > > > spot of a motor.
> >
> >
> > Or, you might just follow the rule of thumb that your motor will be near
> > peak efficiency when operated around 3000-4000RPM, and that at any given
> > vehicle speed the motor current will be lowest when the motor is
> > spinning
> > fastest.
> >
> > Hope this helps,
> >
> > Roger.
> >
> >
> > _______________________________________________
> > | Moratorium on drag racing discussion is in effect.
> > | Please take those discussions elsewhere.  Thanks.
> > |
> > | REPLYING: address your message to [hidden email] only.
> > | Multiple-address or CCed messages may be rejected.
> > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > | OTHER HELP: http://evdl.org/help/
> > | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
> >
> -------------- next part --------------
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> URL:
> http://lists.sjsu.edu/mailman/private/ev/attachments/20110529/77892961/attachment.html
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
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Re: 12,000 miles and 5 controllers later

Peter Gabrielsson
In reply to this post by David Sharpe
The Kelly and Logisystems controllers are well known for letting the
magic smoke out.


On Fri, May 27, 2011 at 6:22 PM, David Sharpe <[hidden email]> wrote:

> I wonder if there is something wrong with your motor. The controllers should
> be self protecting. See if you have a short in the armature or less likely
> the field winding. This can be done by setting up a video camera to look at
> the commutator (remove the screen around the commutator) & go for a drive.
> See if there is much sparking. You may also have an excessively advanced
> brush timing. I blew my reconditioned Raptor 1200A after only 60 miles. I
> dont think it is motor related though. The manual for the Raptor refers to a
> "wild ride" if you get a blown controller. My EV took off like a 911 Porsche
> with squealing wheels,  clutch until the Mosfets burnt out. Lucky not to hit
> any body /things. David Sharpe
>
> --------------------------------------------------
> From: "Tom H" <[hidden email]>
> Sent: Saturday, May 28, 2011 4:46 AM
> To: <[hidden email]>
> Subject: [EVDL] 12,000 miles and 5 controllers later
>
>> After three years and 12,000 miles on my converted pick-up, I would like
>> to
>> share some of my experiences with the discussion list.  Maybe something I
>> say here will help someone just starting to avoid some of the mistakes I
>> have made.
>>
>> _______________________________________________
>> | Moratorium on drag racing discussion is in effect.
>> | Please take those discussions elsewhere.  Thanks.
>> |
>> | REPLYING: address your message to [hidden email] only.
>> | Multiple-address or CCed messages may be rejected.
>> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
>> | OTHER HELP: http://evdl.org/help/
>> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>



--
www.electric-lemon.com

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
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Re: 12,000 miles and 5 controllers later

Cor van de Water
In reply to this post by Roland Wiench
Please note that when you rotate *one* tire, the
diff will add another 2:1 ratio unless you have a
sports car with LSD or rotate both tires at the
same time (not easy).
So please correct for the 2:1 by rotating the one
tire twice to find the motor RPM to wheel RPM relation
of the transmission plus normal diff ratios.
 
Regards,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [hidden email]    Private: http://www.cvandewater.com
Skype: cor_van_de_water     XoIP: +31877841130
Tel: +1 408 383 7626        Tel: +91 (040)23117400 x203

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On
Behalf Of Roland Wiench
Sent: Sunday, May 29, 2011 7:05 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] 12,000 miles and 5 controllers later

Hello Peter,

The sweet spot data is what I received from NetGain for a 9 and 11 inch
motor.

You can convert the speedometer to a rpm indicator using the following
knowns:

Find the running circumference of the tire.  It is known that the same
type and diameter tire at the same air pressure will have a different
running circumference on different vehicles at different weight and
speeds.

I learn about this way back in the 50's when I was doing road rallies
where you may drive a vehicles for 39.5 mph for 18.5 miles and then turn
left.  If there is no road to the left to turn on, then your
calculations are off.

After the EV is built and the tires are air up to the pressure, but not
exceeding the max psi air pressure at maximum load that is on the side
of the tire, then you can find the running circumference.

On a smooth dried road surface, put a mark on the tire and on the road.
Move the vehicle so the tire makes one turn until that tire mark is next
to the road surface again.  Then measure the distance between the two
marks on the road.

Lets say its 85 inches which we call TC.

Now we have to find the overall gear ratio in each gear.  This is easier
with a electric motor then with a engine.  While the motor and
transmission is in the vehicle and the tires are off the ground, put a
mark on the tire, so you can keep track of one turn of the tire.

If the motor has a input shaft on the front of the motor, then you can
use the keyway position to keep track how many turns it takes for the
motor turns while the tire turns one time.

If the motor does not have a input shaft, then remove the brush cover
and put a piece of tape on the communtator to keep track of the number
of rotations.

Now shift the transmission into 1st gear and rotate the tire by hand
counter clock wise which would be the forward direction.  If you rotate
the tire one turn and the motor goes 10 turns, then your overall gear
ratio is 10:1 in 1st gear.

Now shift the transmission into 2nd gear and repeat the operation.

We then now know the two known, the tire running circumference or TC and
the overall gear ratios in each transmission gears or OR.

We now converter the MPH formula to a RPM formula:

                   MPH x OR x 1056
           RPM =   ----------------
                         TC

Now calculated the RPM for each 5 mph for increase of speed as for
example in first gear at 5 mph with a overall gear ratio of 10:1 and a
tire circumference of 85 inches becomes:


                    5 mph x 10 OA  x 1056
             RPM =  ---------------------  = 621 rpm
                            85 in.


At 621 rpm, the speedo will read 5 mph in first gear.

I then find the maximum mph indication at the maximum rated motor rpm
and the mph for the sweet spot rpm.

Roland



----- Original Message -----
From: "SLPinfo.org" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Sunday, May 29, 2011 6:41 AM
Subject: Re: [EVDL] 12,000 miles and 5 controllers later


> Roger,
> First let me say that I really and truly do appreciate you taking the
time
> to compose your detailed response to me about Roland's "sweet spot". I
> respect that your time is valuable and that you give of it freely.
> However, such detailed explanations usually result in my eyes glazing
over
> and me mumbling to myself "what's the bottom line". I don't often read
all
> the long messages that show up sometimes beyond the first paragraph
for
> that
> reason. My EV is basic transportation to me - it's not a hobby. I just

> want
> it to work efficiently. I don't have the time or the mental energy to
work
> through what for me are highly complex electrical, mechanical, or
> engineering details. I realize that for many on this list those
details
> are
> inherently interesting but for me they are not. But I don't want
anyone to
> quit posting such messages for that reason. I can hit the delete
button
> just
> as easily as anyone else and I don't have a problem doing so.
> Another point is that although I have a tach it doesn't work. Despite
> many,
> many attempts using many different suggestions from the EV list I've
never
> been able to get it to work. I'm in the process of having my EV
components
> transferred from one vehicle to another, but I am not going to bother
> having
> the tach installed. Notice that I said "having it installed". I can do

> some
> really basic stuff on my EV, but I'm not an engineer or a mechanic so
I
> have
> to pay someone else to do it.
> Roland's notion of a sweet spot was interesting to me because in
waiting
> to
> get my newer EV (97 S-10 instead of a 91 Plymouth Colt) I'm trying to
> figure
> out optimum speeds for driving in each gear and shifting. I have
formulae
> for computing speeds from both Roland's posts and Mike Brown's Convert
it
> book, but the key number I've always been missing is RPM. No one has
ever
> told me what's the "optimum" rpm or the "maximum" rpm or the "shift
point"
> rpm that I should be aiming for. Without a tach I have to use my
> speedometer
> (and yes my amp guage which I use to measure motor amps, not battery
> amps).
> But the speedometer is most important because I want to avoid tickets
and
> I
> find that if I spend too much time staring at guages I'm not paying
> attention to traffic like I should be. As basic transportation 90% of
my
> EV
> driving is done during rush hour.
> It is interesting that Roland said 3600-3900 rpm would be the sweet
spot
> form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I
had

> never seen either of these sets of numbers before, so I have in fact
> learned
> pretty much what I need to know. Bottom line - even though I couldn't
> follow
> allow the details, YES your response was very helpful!
> - Peter Flipsen Jr
>
> On Fri, May 27, 2011 at 5:15 PM, Roger Stockton
> <[hidden email]>wrote:
>
> > SLPinfo.org wrote:
> >
> > > You have mentioned this "sweet spot" before.  I have tried to find
it
> > > for
> > > my ADC 9", but have not been successful.  I have found torque
curves
> > > (several at this site)
> > >
> >
http://www.evparts.com/products/street-vehicle/motors--dot/96-to-192-vol
t-
> > > street-vehicle-motors/mt2120.htm,
> > > but I'm not an engineer and I don't know how to read them.  I've
tried
> > > contacting Advanced DC, but they basically ignore my emails.
> > > Any idea what the sweet spot might be for my motor?       I run a
120V
> > > system.
> >
> > I'm not sure what Roland means; what he wrote doesn't make much
sense if
> > taken literally:
> >
> > > > Why 1800 rpm?  Because for A WarP 11 motor, this is where the
> > > > maximum
> > HP
> > > > at the maximum torque is develop in this motor which is call the

> > > > sweet
> > > > spot of a motor.
> >
> >
> > Or, you might just follow the rule of thumb that your motor will be
near
> > peak efficiency when operated around 3000-4000RPM, and that at any
given

> > vehicle speed the motor current will be lowest when the motor is
> > spinning
> > fastest.
> >
> > Hope this helps,
> >
> > Roger.
> >
> >
> > _______________________________________________
> > | Moratorium on drag racing discussion is in effect.
> > | Please take those discussions elsewhere.  Thanks.
> > |
> > | REPLYING: address your message to [hidden email] only.
> > | Multiple-address or CCed messages may be rejected.
> > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > | OTHER HELP: http://evdl.org/help/
> > | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
> >
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
>
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ttachment.html

> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
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| OTHER HELP: http://evdl.org/help/
| CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
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Re: 12,000 miles and 5 controllers later

Roland Wiench
Yes, I forgot about that if you have a normal differential.  Another way is
to put the tires on grade and push it until the tire makes
one turn and at the same time find out what the rolling circumference of the
tire is and what the tire side wall deflection measures which should be the
same deflection of the original ICE.

To find this tire deflection while the vehicle is in the ICE configuration,
air the tires to the recommended manufactures PSI.
Then jack both sides of the vehicle so the tires just touches the
floor.  Measure from the distance from the bottom of the wheel rim to the
floor. Lets say this reads 5 inches.

Now lower the vehicle to the floor and read this distance again.  Lets say
it now reads 4.5 inches.  You now have a tire deflection of
0.5 inch which is about normal.

After you complete you EV, repeat this test again. Lets say it now reads
0.385 inch because of the increase weight.  You then increase the air
pressure until the deflection reads 0.500 inch.

You also have to check the maximum load rating of the tire and what
weight you actually have on each tire.  If your load rating is over
the load rating of the tire and you cannot get to the original
deflection rating of the tire with out going over the maximum PSI
rating of the tire, you can get by running slower until you need new
tires.

Roland






----- Original Message -----
From: "Cor van de Water" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Monday, May 30, 2011 12:41 PM
Subject: Re: [EVDL] 12,000 miles and 5 controllers later


> Please note that when you rotate *one* tire, the
> diff will add another 2:1 ratio unless you have a
> sports car with LSD or rotate both tires at the
> same time (not easy).
> So please correct for the 2:1 by rotating the one
> tire twice to find the motor RPM to wheel RPM relation
> of the transmission plus normal diff ratios.
>
> Regards,
>
> Cor van de Water
> Chief Scientist
> Proxim Wireless Corporation http://www.proxim.com
> Email: [hidden email]    Private: http://www.cvandewater.com
> Skype: cor_van_de_water     XoIP: +31877841130
> Tel: +1 408 383 7626        Tel: +91 (040)23117400 x203
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On
> Behalf Of Roland Wiench
> Sent: Sunday, May 29, 2011 7:05 AM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] 12,000 miles and 5 controllers later
>
> Hello Peter,
>
> The sweet spot data is what I received from NetGain for a 9 and 11 inch
> motor.
>
> You can convert the speedometer to a rpm indicator using the following
> knowns:
>
> Find the running circumference of the tire.  It is known that the same
> type and diameter tire at the same air pressure will have a different
> running circumference on different vehicles at different weight and
> speeds.
>
> I learn about this way back in the 50's when I was doing road rallies
> where you may drive a vehicles for 39.5 mph for 18.5 miles and then turn
> left.  If there is no road to the left to turn on, then your
> calculations are off.
>
> After the EV is built and the tires are air up to the pressure, but not
> exceeding the max psi air pressure at maximum load that is on the side
> of the tire, then you can find the running circumference.
>
> On a smooth dried road surface, put a mark on the tire and on the road.
> Move the vehicle so the tire makes one turn until that tire mark is next
> to the road surface again.  Then measure the distance between the two
> marks on the road.
>
> Lets say its 85 inches which we call TC.
>
> Now we have to find the overall gear ratio in each gear.  This is easier
> with a electric motor then with a engine.  While the motor and
> transmission is in the vehicle and the tires are off the ground, put a
> mark on the tire, so you can keep track of one turn of the tire.
>
> If the motor has a input shaft on the front of the motor, then you can
> use the keyway position to keep track how many turns it takes for the
> motor turns while the tire turns one time.
>
> If the motor does not have a input shaft, then remove the brush cover
> and put a piece of tape on the communtator to keep track of the number
> of rotations.
>
> Now shift the transmission into 1st gear and rotate the tire by hand
> counter clock wise which would be the forward direction.  If you rotate
> the tire one turn and the motor goes 10 turns, then your overall gear
> ratio is 10:1 in 1st gear.
>
> Now shift the transmission into 2nd gear and repeat the operation.
>
> We then now know the two known, the tire running circumference or TC and
> the overall gear ratios in each transmission gears or OR.
>
> We now converter the MPH formula to a RPM formula:
>
>                    MPH x OR x 1056
>            RPM =   ----------------
>                          TC
>
> Now calculated the RPM for each 5 mph for increase of speed as for
> example in first gear at 5 mph with a overall gear ratio of 10:1 and a
> tire circumference of 85 inches becomes:
>
>
>                     5 mph x 10 OA  x 1056
>              RPM =  ---------------------  = 621 rpm
>                             85 in.
>
>
> At 621 rpm, the speedo will read 5 mph in first gear.
>
> I then find the maximum mph indication at the maximum rated motor rpm
> and the mph for the sweet spot rpm.
>
> Roland
>
>
>
> ----- Original Message -----
> From: "SLPinfo.org" <[hidden email]>
> To: "Electric Vehicle Discussion List" <[hidden email]>
> Sent: Sunday, May 29, 2011 6:41 AM
> Subject: Re: [EVDL] 12,000 miles and 5 controllers later
>
>
> > Roger,
> > First let me say that I really and truly do appreciate you taking the
> time
> > to compose your detailed response to me about Roland's "sweet spot". I
> > respect that your time is valuable and that you give of it freely.
> > However, such detailed explanations usually result in my eyes glazing
> over
> > and me mumbling to myself "what's the bottom line". I don't often read
> all
> > the long messages that show up sometimes beyond the first paragraph
> for
> > that
> > reason. My EV is basic transportation to me - it's not a hobby. I just
>
> > want
> > it to work efficiently. I don't have the time or the mental energy to
> work
> > through what for me are highly complex electrical, mechanical, or
> > engineering details. I realize that for many on this list those
> details
> > are
> > inherently interesting but for me they are not. But I don't want
> anyone to
> > quit posting such messages for that reason. I can hit the delete
> button
> > just
> > as easily as anyone else and I don't have a problem doing so.
> > Another point is that although I have a tach it doesn't work. Despite
> > many,
> > many attempts using many different suggestions from the EV list I've
> never
> > been able to get it to work. I'm in the process of having my EV
> components
> > transferred from one vehicle to another, but I am not going to bother
> > having
> > the tach installed. Notice that I said "having it installed". I can do
>
> > some
> > really basic stuff on my EV, but I'm not an engineer or a mechanic so
> I
> > have
> > to pay someone else to do it.
> > Roland's notion of a sweet spot was interesting to me because in
> waiting
> > to
> > get my newer EV (97 S-10 instead of a 91 Plymouth Colt) I'm trying to
> > figure
> > out optimum speeds for driving in each gear and shifting. I have
> formulae
> > for computing speeds from both Roland's posts and Mike Brown's Convert
> it
> > book, but the key number I've always been missing is RPM. No one has
> ever
> > told me what's the "optimum" rpm or the "maximum" rpm or the "shift
> point"
> > rpm that I should be aiming for. Without a tach I have to use my
> > speedometer
> > (and yes my amp guage which I use to measure motor amps, not battery
> > amps).
> > But the speedometer is most important because I want to avoid tickets
> and
> > I
> > find that if I spend too much time staring at guages I'm not paying
> > attention to traffic like I should be. As basic transportation 90% of
> my
> > EV
> > driving is done during rush hour.
> > It is interesting that Roland said 3600-3900 rpm would be the sweet
> spot
> > form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I
> had
> > never seen either of these sets of numbers before, so I have in fact
> > learned
> > pretty much what I need to know. Bottom line - even though I couldn't
> > follow
> > allow the details, YES your response was very helpful!
> > - Peter Flipsen Jr
> >
> > On Fri, May 27, 2011 at 5:15 PM, Roger Stockton
> > <[hidden email]>wrote:
> >
> > > SLPinfo.org wrote:
> > >
> > > > You have mentioned this "sweet spot" before.  I have tried to find
> it
> > > > for
> > > > my ADC 9", but have not been successful.  I have found torque
> curves
> > > > (several at this site)
> > > >
> > >
> http://www.evparts.com/products/street-vehicle/motors--dot/96-to-192-vol
> t-
> > > > street-vehicle-motors/mt2120.htm,
> > > > but I'm not an engineer and I don't know how to read them.  I've
> tried
> > > > contacting Advanced DC, but they basically ignore my emails.
> > > > Any idea what the sweet spot might be for my motor?       I run a
> 120V
> > > > system.
> > >
> > > I'm not sure what Roland means; what he wrote doesn't make much
> sense if
> > > taken literally:
> > >
> > > > > Why 1800 rpm?  Because for A WarP 11 motor, this is where the
> > > > > maximum
> > > HP
> > > > > at the maximum torque is develop in this motor which is call the
>
> > > > > sweet
> > > > > spot of a motor.
> > >
> > >
> > > Or, you might just follow the rule of thumb that your motor will be
> near
> > > peak efficiency when operated around 3000-4000RPM, and that at any
> given
> > > vehicle speed the motor current will be lowest when the motor is
> > > spinning
> > > fastest.
> > >
> > > Hope this helps,
> > >
> > > Roger.
> > >
> > >
> > > _______________________________________________
> > > | Moratorium on drag racing discussion is in effect.
> > > | Please take those discussions elsewhere.  Thanks.
> > > |
> > > | REPLYING: address your message to [hidden email] only.
> > > | Multiple-address or CCed messages may be rejected.
> > > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > > | OTHER HELP: http://evdl.org/help/
> > > | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
> > >
> > -------------- next part --------------
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> > URL:
> >
> http://lists.sjsu.edu/mailman/private/ev/attachments/20110529/77892961/a
> ttachment.html
> > _______________________________________________
> > | Moratorium on drag racing discussion is in effect.
> > | Please take those discussions elsewhere.  Thanks.
> > |
> > | REPLYING: address your message to [hidden email] only.
> > | Multiple-address or CCed messages may be rejected.
> > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > | OTHER HELP: http://evdl.org/help/
> > | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
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Re: 12,000 miles and 5 controllers later

Roger Stockton
In reply to this post by SLPinfo.org
SLPinfo.org wrote:

> First let me say that I really and truly do appreciate you taking the time
> to compose your detailed response to me about Roland's "sweet spot". I
> respect that your time is valuable and that you give of it freely.
> However, such detailed explanations usually result in my eyes glazing over
> and me mumbling to myself "what's the bottom line".

Yeah, I get that a lot ;^>

You mentioned that you weren't sure how to read the motor performance charts, so I thought I'd try to walk you through it.  It ended up longer than I expected, but I didn't see a shorter route.

> My EV is basic transportation to me - it's not a hobby. I just
> want it to work efficiently. I don't have the time or the mental
> energy to work through what for me are highly complex electrical,
> mechanical, or engineering details.

My suggestion then is to not sweat worrying about the motor "sweet spot".  The efficiency curve is pretty flat over a wide operating range, so unless you are really lugging your motor or really winding it out the potential efficiency gain (at the motor) is probably in the single digits of efficiency.

> Another point is that although I have a tach it doesn't work.

I haven't gotten around to getting mine working yet either...

> I'm trying to figure out optimum speeds for driving in each gear
> and shifting. I have formulae for computing speeds from both Roland's
> posts and Mike Brown's Convert it book, but the key number I've always
> been missing is RPM. No one has ever told me what's the "optimum" rpm
> or the "maximum" rpm or the "shift point" rpm that I should be aiming
> for. Without a tach I have to use my speedometer (and yes my amp guage
> which I use to measure motor amps, not battery amps).

I'm with you 100% about not wanting to stare at a bunch of gauges.

I don't think you can calculate the optimum speeds for driving or shifting.

You can figure out what the maximum speed you can drive in each gear without over-revving the motor is, but the optimum speeds and gears for overall efficiency depend on the entire system, not just the motor efficiency.  Gaining 1% in the motor efficiency but losing 2% running in 1st gear instead of 2nd costs you efficiency overall.

As for RPM values, back in the day, Rich Rudman posted that ADC recommends 4500RPM *maximum* for the ADC 9".  He notes that in racing the ADC 9" is/has been taken to 6000RPM, but clearly you don't want to run it like that routinely.  Also, note that the material holding the com bars softens when the motor is hot, so the max safe RPM will decrease when the motor is hot.  This may explain the factory recommendation of 4500RPM max even though the drag racers have found the motor to tolerate 6000RPM safely.

Bear in mind that it takes a fair bit of voltage to spin the motor this fast under load; with your modest pack voltage, you are likely to find yourself shifting before the motor is spinning 4000RPM+ simply because the motor will run out of steam before then.

> It is interesting that Roland said 3600-3900 rpm would be the sweet spot
> form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I had
> never seen either of these sets of numbers before, so I have in fact
> learned pretty much what I need to know.

Given that you have a motor current meter, I think you may find it even easier if you just follow Jeff Major's advice (operate the motor so that the motor current stays at or below the 1hr rating, which appears to be about 170A for your motor, except for brief excursions when accelerating, etc.).

Use Roland's or Mike Brown's formulae to figure out what speed in each gear corresponds to 4500RPM and avoid driving faster than that in each gear.  (If you are familiar with older VW Beetle speedos, they have shift suggestions marked on the speedo face for each gear as a I, II, III, or IV next to the appropriate speed; this might be a useful approach for you to take.)

Cheers,

Roger.


_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
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Re: 12,000 miles and 5 controllers later

SLPinfo.org
Roger

Thanks for the straightforward and rational response.  Have now calculated
max speeds. With my previous EV I was able to keep the motor amps in the
100-150 range most of the time.  Will be interesting to see how it goes with
a heavier and less aerodynamic vehicle.

Peter
On May 30, 2011 3:45 PM, "Roger Stockton" <[hidden email]> wrote:
> SLPinfo.org wrote:
>
>> First let me say that I really and truly do appreciate you taking the
time
>> to compose your detailed response to me about Roland's "sweet spot". I
>> respect that your time is valuable and that you give of it freely.
>> However, such detailed explanations usually result in my eyes glazing
over
>> and me mumbling to myself "what's the bottom line".
>
> Yeah, I get that a lot ;^>
>
> You mentioned that you weren't sure how to read the motor performance
charts, so I thought I'd try to walk you through it. It ended up longer than
I expected, but I didn't see a shorter route.
>
>> My EV is basic transportation to me - it's not a hobby. I just
>> want it to work efficiently. I don't have the time or the mental
>> energy to work through what for me are highly complex electrical,
>> mechanical, or engineering details.
>
> My suggestion then is to not sweat worrying about the motor "sweet spot".
The efficiency curve is pretty flat over a wide operating range, so unless
you are really lugging your motor or really winding it out the potential
efficiency gain (at the motor) is probably in the single digits of
efficiency.

>
>> Another point is that although I have a tach it doesn't work.
>
> I haven't gotten around to getting mine working yet either...
>
>> I'm trying to figure out optimum speeds for driving in each gear
>> and shifting. I have formulae for computing speeds from both Roland's
>> posts and Mike Brown's Convert it book, but the key number I've always
>> been missing is RPM. No one has ever told me what's the "optimum" rpm
>> or the "maximum" rpm or the "shift point" rpm that I should be aiming
>> for. Without a tach I have to use my speedometer (and yes my amp guage
>> which I use to measure motor amps, not battery amps).
>
> I'm with you 100% about not wanting to stare at a bunch of gauges.
>
> I don't think you can calculate the optimum speeds for driving or
shifting.
>
> You can figure out what the maximum speed you can drive in each gear
without over-revving the motor is, but the optimum speeds and gears for
overall efficiency depend on the entire system, not just the motor
efficiency. Gaining 1% in the motor efficiency but losing 2% running in 1st
gear instead of 2nd costs you efficiency overall.
>
> As for RPM values, back in the day, Rich Rudman posted that ADC recommends
4500RPM *maximum* for the ADC 9". He notes that in racing the ADC 9" is/has
been taken to 6000RPM, but clearly you don't want to run it like that
routinely. Also, note that the material holding the com bars softens when
the motor is hot, so the max safe RPM will decrease when the motor is hot.
This may explain the factory recommendation of 4500RPM max even though the
drag racers have found the motor to tolerate 6000RPM safely.
>
> Bear in mind that it takes a fair bit of voltage to spin the motor this
fast under load; with your modest pack voltage, you are likely to find
yourself shifting before the motor is spinning 4000RPM+ simply because the
motor will run out of steam before then.
>
>> It is interesting that Roland said 3600-3900 rpm would be the sweet spot
>> form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I had
>> never seen either of these sets of numbers before, so I have in fact
>> learned pretty much what I need to know.
>
> Given that you have a motor current meter, I think you may find it even
easier if you just follow Jeff Major's advice (operate the motor so that the
motor current stays at or below the 1hr rating, which appears to be about
170A for your motor, except for brief excursions when accelerating, etc.).
>
> Use Roland's or Mike Brown's formulae to figure out what speed in each
gear corresponds to 4500RPM and avoid driving faster than that in each gear.
(If you are familiar with older VW Beetle speedos, they have shift
suggestions marked on the speedo face for each gear as a I, II, III, or IV
next to the appropriate speed; this might be a useful approach for you to
take.)

>
> Cheers,
>
> Roger.
>
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere. Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
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| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
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please remove from this list

Karl Greenblatt

Anarchism is founded on the observation that since few men are wise enough
to rule themselves, even fewer are wise enough to rule others-Ed Abbey


----- Original Message -----
From: "SLPinfo.org" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Monday, May 30, 2011 5:35 PM
Subject: Re: [EVDL] 12,000 miles and 5 controllers later


> Roger
>
> Thanks for the straightforward and rational response.  Have now calculated
> max speeds. With my previous EV I was able to keep the motor amps in the
> 100-150 range most of the time.  Will be interesting to see how it goes
> with
> a heavier and less aerodynamic vehicle.
>
> Peter
> On May 30, 2011 3:45 PM, "Roger Stockton" <[hidden email]> wrote:
>> SLPinfo.org wrote:
>>
>>> First let me say that I really and truly do appreciate you taking the
> time
>>> to compose your detailed response to me about Roland's "sweet spot". I
>>> respect that your time is valuable and that you give of it freely.
>>> However, such detailed explanations usually result in my eyes glazing
> over
>>> and me mumbling to myself "what's the bottom line".
>>
>> Yeah, I get that a lot ;^>
>>
>> You mentioned that you weren't sure how to read the motor performance
> charts, so I thought I'd try to walk you through it. It ended up longer
> than
> I expected, but I didn't see a shorter route.
>>
>>> My EV is basic transportation to me - it's not a hobby. I just
>>> want it to work efficiently. I don't have the time or the mental
>>> energy to work through what for me are highly complex electrical,
>>> mechanical, or engineering details.
>>
>> My suggestion then is to not sweat worrying about the motor "sweet spot".
> The efficiency curve is pretty flat over a wide operating range, so unless
> you are really lugging your motor or really winding it out the potential
> efficiency gain (at the motor) is probably in the single digits of
> efficiency.
>>
>>> Another point is that although I have a tach it doesn't work.
>>
>> I haven't gotten around to getting mine working yet either...
>>
>>> I'm trying to figure out optimum speeds for driving in each gear
>>> and shifting. I have formulae for computing speeds from both Roland's
>>> posts and Mike Brown's Convert it book, but the key number I've always
>>> been missing is RPM. No one has ever told me what's the "optimum" rpm
>>> or the "maximum" rpm or the "shift point" rpm that I should be aiming
>>> for. Without a tach I have to use my speedometer (and yes my amp guage
>>> which I use to measure motor amps, not battery amps).
>>
>> I'm with you 100% about not wanting to stare at a bunch of gauges.
>>
>> I don't think you can calculate the optimum speeds for driving or
> shifting.
>>
>> You can figure out what the maximum speed you can drive in each gear
> without over-revving the motor is, but the optimum speeds and gears for
> overall efficiency depend on the entire system, not just the motor
> efficiency. Gaining 1% in the motor efficiency but losing 2% running in
> 1st
> gear instead of 2nd costs you efficiency overall.
>>
>> As for RPM values, back in the day, Rich Rudman posted that ADC
>> recommends
> 4500RPM *maximum* for the ADC 9". He notes that in racing the ADC 9"
> is/has
> been taken to 6000RPM, but clearly you don't want to run it like that
> routinely. Also, note that the material holding the com bars softens when
> the motor is hot, so the max safe RPM will decrease when the motor is hot.
> This may explain the factory recommendation of 4500RPM max even though the
> drag racers have found the motor to tolerate 6000RPM safely.
>>
>> Bear in mind that it takes a fair bit of voltage to spin the motor this
> fast under load; with your modest pack voltage, you are likely to find
> yourself shifting before the motor is spinning 4000RPM+ simply because the
> motor will run out of steam before then.
>>
>>> It is interesting that Roland said 3600-3900 rpm would be the sweet spot
>>> form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I had
>>> never seen either of these sets of numbers before, so I have in fact
>>> learned pretty much what I need to know.
>>
>> Given that you have a motor current meter, I think you may find it even
> easier if you just follow Jeff Major's advice (operate the motor so that
> the
> motor current stays at or below the 1hr rating, which appears to be about
> 170A for your motor, except for brief excursions when accelerating, etc.).
>>
>> Use Roland's or Mike Brown's formulae to figure out what speed in each
> gear corresponds to 4500RPM and avoid driving faster than that in each
> gear.
> (If you are familiar with older VW Beetle speedos, they have shift
> suggestions marked on the speedo face for each gear as a I, II, III, or IV
> next to the appropriate speed; this might be a useful approach for you to
> take.)
>>
>> Cheers,
>>
>> Roger.
>>
>>
>> _______________________________________________
>> | Moratorium on drag racing discussion is in effect.
>> | Please take those discussions elsewhere. Thanks.
>> |
>> | REPLYING: address your message to [hidden email] only.
>> | Multiple-address or CCed messages may be rejected.
>> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
>> | OTHER HELP: http://evdl.org/help/
>> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
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Re: please remove from this list

David Nelson-5
Then why not follow the unsubscribe link at the bottom of every email
sent to the list? Given that no one here is trying to rule any one I
think your quote is ironic, given that you didn't just unsubscribe.

On Mon, May 30, 2011 at 6:36 PM, Karl Greenblatt <[hidden email]> wrote:

>
> Anarchism is founded on the observation that since few men are wise enough
> to rule themselves, even fewer are wise enough to rule others-Ed Abbey
>
>
> ----- Original Message -----
> From: "SLPinfo.org" <[hidden email]>
> To: "Electric Vehicle Discussion List" <[hidden email]>
> Sent: Monday, May 30, 2011 5:35 PM
> Subject: Re: [EVDL] 12,000 miles and 5 controllers later
>
>
> > Roger
> >
> > Thanks for the straightforward and rational response.  Have now calculated
> > max speeds. With my previous EV I was able to keep the motor amps in the
> > 100-150 range most of the time.  Will be interesting to see how it goes
> > with
> > a heavier and less aerodynamic vehicle.
> >
> > Peter
> > On May 30, 2011 3:45 PM, "Roger Stockton" <[hidden email]> wrote:
> >> SLPinfo.org wrote:
> >>
> >>> First let me say that I really and truly do appreciate you taking the
> > time
> >>> to compose your detailed response to me about Roland's "sweet spot". I
> >>> respect that your time is valuable and that you give of it freely.
> >>> However, such detailed explanations usually result in my eyes glazing
> > over
> >>> and me mumbling to myself "what's the bottom line".
> >>
> >> Yeah, I get that a lot ;^>
> >>
> >> You mentioned that you weren't sure how to read the motor performance
> > charts, so I thought I'd try to walk you through it. It ended up longer
> > than
> > I expected, but I didn't see a shorter route.
> >>
> >>> My EV is basic transportation to me - it's not a hobby. I just
> >>> want it to work efficiently. I don't have the time or the mental
> >>> energy to work through what for me are highly complex electrical,
> >>> mechanical, or engineering details.
> >>
> >> My suggestion then is to not sweat worrying about the motor "sweet spot".
> > The efficiency curve is pretty flat over a wide operating range, so unless
> > you are really lugging your motor or really winding it out the potential
> > efficiency gain (at the motor) is probably in the single digits of
> > efficiency.
> >>
> >>> Another point is that although I have a tach it doesn't work.
> >>
> >> I haven't gotten around to getting mine working yet either...
> >>
> >>> I'm trying to figure out optimum speeds for driving in each gear
> >>> and shifting. I have formulae for computing speeds from both Roland's
> >>> posts and Mike Brown's Convert it book, but the key number I've always
> >>> been missing is RPM. No one has ever told me what's the "optimum" rpm
> >>> or the "maximum" rpm or the "shift point" rpm that I should be aiming
> >>> for. Without a tach I have to use my speedometer (and yes my amp guage
> >>> which I use to measure motor amps, not battery amps).
> >>
> >> I'm with you 100% about not wanting to stare at a bunch of gauges.
> >>
> >> I don't think you can calculate the optimum speeds for driving or
> > shifting.
> >>
> >> You can figure out what the maximum speed you can drive in each gear
> > without over-revving the motor is, but the optimum speeds and gears for
> > overall efficiency depend on the entire system, not just the motor
> > efficiency. Gaining 1% in the motor efficiency but losing 2% running in
> > 1st
> > gear instead of 2nd costs you efficiency overall.
> >>
> >> As for RPM values, back in the day, Rich Rudman posted that ADC
> >> recommends
> > 4500RPM *maximum* for the ADC 9". He notes that in racing the ADC 9"
> > is/has
> > been taken to 6000RPM, but clearly you don't want to run it like that
> > routinely. Also, note that the material holding the com bars softens when
> > the motor is hot, so the max safe RPM will decrease when the motor is hot.
> > This may explain the factory recommendation of 4500RPM max even though the
> > drag racers have found the motor to tolerate 6000RPM safely.
> >>
> >> Bear in mind that it takes a fair bit of voltage to spin the motor this
> > fast under load; with your modest pack voltage, you are likely to find
> > yourself shifting before the motor is spinning 4000RPM+ simply because the
> > motor will run out of steam before then.
> >>
> >>> It is interesting that Roland said 3600-3900 rpm would be the sweet spot
> >>> form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I had
> >>> never seen either of these sets of numbers before, so I have in fact
> >>> learned pretty much what I need to know.
> >>
> >> Given that you have a motor current meter, I think you may find it even
> > easier if you just follow Jeff Major's advice (operate the motor so that
> > the
> > motor current stays at or below the 1hr rating, which appears to be about
> > 170A for your motor, except for brief excursions when accelerating, etc.).
> >>
> >> Use Roland's or Mike Brown's formulae to figure out what speed in each
> > gear corresponds to 4500RPM and avoid driving faster than that in each
> > gear.
> > (If you are familiar with older VW Beetle speedos, they have shift
> > suggestions marked on the speedo face for each gear as a I, II, III, or IV
> > next to the appropriate speed; this might be a useful approach for you to
> > take.)
> >>
> >> Cheers,
> >>
> >> Roger.
> >>
> >>
> >> _______________________________________________
> >> | Moratorium on drag racing discussion is in effect.
> >> | Please take those discussions elsewhere. Thanks.
> >> |
> >> | REPLYING: address your message to [hidden email] only.
> >> | Multiple-address or CCed messages may be rejected.
> >> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> >> | OTHER HELP: http://evdl.org/help/
> >> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> > URL:
> > http://lists.sjsu.edu/mailman/private/ev/attachments/20110530/6e54898e/attachment.html
> > _______________________________________________
> > | Moratorium on drag racing discussion is in effect.
> > | Please take those discussions elsewhere.  Thanks.
> > |
> > | REPLYING: address your message to [hidden email] only.
> > | Multiple-address or CCed messages may be rejected.
> > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > | OTHER HELP: http://evdl.org/help/
> > | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere.  Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev



--
David D. Nelson
http://evalbum.com/1328

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
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Re: please remove from this list

Karl Greenblatt
Thanks for the suggestion the thing is "I tried that"

Anarchism is founded on the observation that since few men are wise enough
to rule themselves, even fewer are wise enough to rule others-Ed Abbey


----- Original Message -----
From: "David Nelson" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Cc: <[hidden email]>
Sent: Monday, May 30, 2011 6:58 PM
Subject: Re: [EVDL] please remove from this list


Then why not follow the unsubscribe link at the bottom of every email
sent to the list? Given that no one here is trying to rule any one I
think your quote is ironic, given that you didn't just unsubscribe.

On Mon, May 30, 2011 at 6:36 PM, Karl Greenblatt <[hidden email]> wrote:

>
> Anarchism is founded on the observation that since few men are wise enough
> to rule themselves, even fewer are wise enough to rule others-Ed Abbey
>
>
> ----- Original Message -----
> From: "SLPinfo.org" <[hidden email]>
> To: "Electric Vehicle Discussion List" <[hidden email]>
> Sent: Monday, May 30, 2011 5:35 PM
> Subject: Re: [EVDL] 12,000 miles and 5 controllers later
>
>
> > Roger
> >
> > Thanks for the straightforward and rational response. Have now
> > calculated
> > max speeds. With my previous EV I was able to keep the motor amps in the
> > 100-150 range most of the time. Will be interesting to see how it goes
> > with
> > a heavier and less aerodynamic vehicle.
> >
> > Peter
> > On May 30, 2011 3:45 PM, "Roger Stockton" <[hidden email]> wrote:
> >> SLPinfo.org wrote:
> >>
> >>> First let me say that I really and truly do appreciate you taking the
> > time
> >>> to compose your detailed response to me about Roland's "sweet spot". I
> >>> respect that your time is valuable and that you give of it freely.
> >>> However, such detailed explanations usually result in my eyes glazing
> > over
> >>> and me mumbling to myself "what's the bottom line".
> >>
> >> Yeah, I get that a lot ;^>
> >>
> >> You mentioned that you weren't sure how to read the motor performance
> > charts, so I thought I'd try to walk you through it. It ended up longer
> > than
> > I expected, but I didn't see a shorter route.
> >>
> >>> My EV is basic transportation to me - it's not a hobby. I just
> >>> want it to work efficiently. I don't have the time or the mental
> >>> energy to work through what for me are highly complex electrical,
> >>> mechanical, or engineering details.
> >>
> >> My suggestion then is to not sweat worrying about the motor "sweet
> >> spot".
> > The efficiency curve is pretty flat over a wide operating range, so
> > unless
> > you are really lugging your motor or really winding it out the potential
> > efficiency gain (at the motor) is probably in the single digits of
> > efficiency.
> >>
> >>> Another point is that although I have a tach it doesn't work.
> >>
> >> I haven't gotten around to getting mine working yet either...
> >>
> >>> I'm trying to figure out optimum speeds for driving in each gear
> >>> and shifting. I have formulae for computing speeds from both Roland's
> >>> posts and Mike Brown's Convert it book, but the key number I've always
> >>> been missing is RPM. No one has ever told me what's the "optimum" rpm
> >>> or the "maximum" rpm or the "shift point" rpm that I should be aiming
> >>> for. Without a tach I have to use my speedometer (and yes my amp guage
> >>> which I use to measure motor amps, not battery amps).
> >>
> >> I'm with you 100% about not wanting to stare at a bunch of gauges.
> >>
> >> I don't think you can calculate the optimum speeds for driving or
> > shifting.
> >>
> >> You can figure out what the maximum speed you can drive in each gear
> > without over-revving the motor is, but the optimum speeds and gears for
> > overall efficiency depend on the entire system, not just the motor
> > efficiency. Gaining 1% in the motor efficiency but losing 2% running in
> > 1st
> > gear instead of 2nd costs you efficiency overall.
> >>
> >> As for RPM values, back in the day, Rich Rudman posted that ADC
> >> recommends
> > 4500RPM *maximum* for the ADC 9". He notes that in racing the ADC 9"
> > is/has
> > been taken to 6000RPM, but clearly you don't want to run it like that
> > routinely. Also, note that the material holding the com bars softens
> > when
> > the motor is hot, so the max safe RPM will decrease when the motor is
> > hot.
> > This may explain the factory recommendation of 4500RPM max even though
> > the
> > drag racers have found the motor to tolerate 6000RPM safely.
> >>
> >> Bear in mind that it takes a fair bit of voltage to spin the motor this
> > fast under load; with your modest pack voltage, you are likely to find
> > yourself shifting before the motor is spinning 4000RPM+ simply because
> > the
> > motor will run out of steam before then.
> >>
> >>> It is interesting that Roland said 3600-3900 rpm would be the sweet
> >>> spot
> >>> form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I
> >>> had
> >>> never seen either of these sets of numbers before, so I have in fact
> >>> learned pretty much what I need to know.
> >>
> >> Given that you have a motor current meter, I think you may find it even
> > easier if you just follow Jeff Major's advice (operate the motor so that
> > the
> > motor current stays at or below the 1hr rating, which appears to be
> > about
> > 170A for your motor, except for brief excursions when accelerating,
> > etc.).
> >>
> >> Use Roland's or Mike Brown's formulae to figure out what speed in each
> > gear corresponds to 4500RPM and avoid driving faster than that in each
> > gear.
> > (If you are familiar with older VW Beetle speedos, they have shift
> > suggestions marked on the speedo face for each gear as a I, II, III, or
> > IV
> > next to the appropriate speed; this might be a useful approach for you
> > to
> > take.)
> >>
> >> Cheers,
> >>
> >> Roger.
> >>
> >>
> >> _______________________________________________
> >> | Moratorium on drag racing discussion is in effect.
> >> | Please take those discussions elsewhere. Thanks.
> >> |
> >> | REPLYING: address your message to [hidden email] only.
> >> | Multiple-address or CCed messages may be rejected.
> >> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> >> | OTHER HELP: http://evdl.org/help/
> >> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> > URL:
> > http://lists.sjsu.edu/mailman/private/ev/attachments/20110530/6e54898e/attachment.html
> > _______________________________________________
> > | Moratorium on drag racing discussion is in effect.
> > | Please take those discussions elsewhere. Thanks.
> > |
> > | REPLYING: address your message to [hidden email] only.
> > | Multiple-address or CCed messages may be rejected.
> > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > | OTHER HELP: http://evdl.org/help/
> > | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere. Thanks.
> |
> | REPLYING: address your message to [hidden email] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev



--
David D. Nelson
http://evalbum.com/1328 

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere.  Thanks.
|
| REPLYING: address your message to [hidden email] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
12