Electric motor with no tranny for conversion

classic Classic list List threaded Threaded
93 messages Options
12345
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Lee Hart
Lee Hart wrote:
>> Essentially all vehicles built as EVs from scratch have no
>> transmissions (electric cars, trains, buses, golf carts, fork
>> lifts, etc.)

Peter VanDerWal wrote:
> We aren't talking about Golf Carts, or even purpose build EVs. We are
> talking about converting a MUSTANG and connecting the electric motor
> directly to the differential. In THIS situation, the adverbs apply...

Today, we drove Michael Shoop's Volt Vette (1987 Corvette EV conversion)
for the first time. It has a Zilla 2K controller, Netgain TransWarP 11"
motor, 2.73:1 differential, and no transmission. We turned the Zilla
down to just 250 max battery amps, and 500 max motor amps.

It *still* has plenty of power. Enough, in fact, to climb right over the
4" high bump stops on the trailer, and nearly drive into the tow vehicle!

> At 30 mph, the motor is going to be turning at about 1,000 rpm or
> less (depends on the exact diff ratio)... Assuming a 9" ADC or
> equivalent, and given the lower voltage needed at 30 mph, this low
> RPM will only be about 65% efficient

As I said, you want a bigger motor and controller for a transmissionless
vehicle, and the differential ratio should be significantly increased. A
9" motor would be a bit small for an over-3000 lbs transmissionless
conversion.

The efficiency won't be as bad as 65% unless you don't change the
differential ratio, and are driving up a hill or accelerating hard so
motor current is high. Look at the curves for that ADC 9" motor;
efficiency is over 80% from 10 to 120 ft.lbs of torque and 1000-5000 RPM.

> (not counting the extra power required by the cooling fan)

The external blower for a traction motor uses something like 10 amps at
12 volts. That's not much; only a couple percent of total power.

> Assuming you never need to climb hills.  If you do have any hills
> you'll need closer to 3:1 (i.e the typical difference between 1st/2nd
> and 4th/5th)

I can't remember any hill steep enough to require me to use 1st gear in
any of my EVs. Likewise, I've never needed the highest gear (4th or
5th), because it slows the motor so far that you don't get adequate cooling.

>> Note that you will need to replace your differential gears to go
>> transmissionless. A typical ICE car differential ratio is around
>> 3:1. The differential for a transmissionless EV is more like 5:1.

> Or 10:1 as found in many purpose built EVs

Only the ones with 13,000 RPM AC motors.

>>> Also, while electric motors are very efficient over a wide band
>>> of RPMs, efficiency tends to fall off quickly at very low and
>>> very high RPMs.

>> Yes; except that your driving time at very low and very high speeds
>> is generally quite low.

> Unless you drive in traffic.

Hmm... I *do* drive in traffic. In fact, *most* of my EV driving has
been on residential streets, or crowded freeways with lots of
stop-and-go traffic. Still, I find that I almost always leave it in one
gear.

If your driving style is to always accelerate as fast as possible, a
direct drive EV may not be for you. It would require a much larger motor
and controller to match the performance you could get with a transmission.

But, if you're talking about normal driving, where acceleration is
limited by the car ahead of you, or stop signs every block, or
creep-stop-creep-stop on a crowded freeway, then a single speed setup is
not really a handicap.

>>> around town driving will be less efficient without the tranny.
>> In fact, I leave my EV in 2nd gear for almost all around-town
>> driving, because it's *more* efficient than shifting.
>
> Try leaving it in 4th, since that is effectively we are talking
> about.

No; I think it is a mistake to go transmissionless without also changing
the differential ratio. My Renault LeCar has a transaxle, so I can't
change it to a 5:1 ratio and eliminate the transmission. But the
original poster *can* change his differential to 5:1 and remove the
transmission. It will be like driving in 3rd gear all the time -- and
that *does* work for any EV that has a slightly larger motor and controller.

> It's easy to win an argument by changing the basic assumptions.

I'm not arguing, Peter. Everything you've said is true; but I believe
you are giving them too much emphasis. Almost all well designed EVs
don't use a transmission. There's a reason for that -- they don't *need*
a transmission if the ratio is chosen right!
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Peter VanDerWal
Lee, I expected better from you.

It's not just about how MUCH torque you can generate, it's about how LONG
you can generate it.

Assuming a fairly normal conversion of our Mustang (except for the missing
tranny), even with a 5:1 diff ratio my calculations indicate that climbing
an 8% hill (pretty common) requires around 400 amps for a 9" ADC and
around 360 amps with a transwarp 11".

The Zilla 1K is only rated for 300 amps continuous.  So unless the hill is
pretty short, it won't make it up.  If it has to spend more than a minute
or so climbing it, the maximum hill the 9" ADC & Z1k combo can handle is
about 5%
You'd need either the Z2k and a TW 11" or the Z1k and the TW 13" if you
want to climb some of the steeper, but still common hills (6-10%) of any
length.

That's why I said you'll need more than double the rated motor/controller
combo if you are planing on climbing hills.

I'll grant you my efficiency estimates were off.  I had (incorrectly)
assumed that replacing the ring and pinion gears would be very expensive.
I'd looked into doing this for a 4runner differential a few years back and
the prices I came up with were in the $500-$600 price range.
I figured the beefier ones used in the Ford 9" would cost more, but I
guess it's one of those supply and demand things.  I checked a couple
places online and the 9" ones can be purchased for less than $200.

It still adds cost to the conversion, but a 5:1 R&P would make it doable.
Assuming you are willing to shell out the big bucks for the oversized
motor& controller


> Lee Hart wrote:
>>> Essentially all vehicles built as EVs from scratch have no
>>> transmissions (electric cars, trains, buses, golf carts, fork
>>> lifts, etc.)
>
> Peter VanDerWal wrote:
>> We aren't talking about Golf Carts, or even purpose build EVs. We are
>> talking about converting a MUSTANG and connecting the electric motor
>> directly to the differential. In THIS situation, the adverbs apply...
>
> Today, we drove Michael Shoop's Volt Vette (1987 Corvette EV conversion)
> for the first time. It has a Zilla 2K controller, Netgain TransWarP 11"
> motor, 2.73:1 differential, and no transmission. We turned the Zilla
> down to just 250 max battery amps, and 500 max motor amps.
>
> It *still* has plenty of power. Enough, in fact, to climb right over the
> 4" high bump stops on the trailer, and nearly drive into the tow vehicle!
>
>> At 30 mph, the motor is going to be turning at about 1,000 rpm or
>> less (depends on the exact diff ratio)... Assuming a 9" ADC or
>> equivalent, and given the lower voltage needed at 30 mph, this low
>> RPM will only be about 65% efficient
>
> As I said, you want a bigger motor and controller for a transmissionless
> vehicle, and the differential ratio should be significantly increased. A
> 9" motor would be a bit small for an over-3000 lbs transmissionless
> conversion.
>
> The efficiency won't be as bad as 65% unless you don't change the
> differential ratio, and are driving up a hill or accelerating hard so
> motor current is high. Look at the curves for that ADC 9" motor;
> efficiency is over 80% from 10 to 120 ft.lbs of torque and 1000-5000 RPM.
>
>> (not counting the extra power required by the cooling fan)
>
> The external blower for a traction motor uses something like 10 amps at
> 12 volts. That's not much; only a couple percent of total power.
>
>> Assuming you never need to climb hills.  If you do have any hills
>> you'll need closer to 3:1 (i.e the typical difference between 1st/2nd
>> and 4th/5th)
>
> I can't remember any hill steep enough to require me to use 1st gear in
> any of my EVs. Likewise, I've never needed the highest gear (4th or
> 5th), because it slows the motor so far that you don't get adequate
> cooling.
>
>>> Note that you will need to replace your differential gears to go
>>> transmissionless. A typical ICE car differential ratio is around
>>> 3:1. The differential for a transmissionless EV is more like 5:1.
>
>> Or 10:1 as found in many purpose built EVs
>
> Only the ones with 13,000 RPM AC motors.
>
>>>> Also, while electric motors are very efficient over a wide band
>>>> of RPMs, efficiency tends to fall off quickly at very low and
>>>> very high RPMs.
>
>>> Yes; except that your driving time at very low and very high speeds
>>> is generally quite low.
>
>> Unless you drive in traffic.
>
> Hmm... I *do* drive in traffic. In fact, *most* of my EV driving has
> been on residential streets, or crowded freeways with lots of
> stop-and-go traffic. Still, I find that I almost always leave it in one
> gear.
>
> If your driving style is to always accelerate as fast as possible, a
> direct drive EV may not be for you. It would require a much larger motor
> and controller to match the performance you could get with a transmission.
>
> But, if you're talking about normal driving, where acceleration is
> limited by the car ahead of you, or stop signs every block, or
> creep-stop-creep-stop on a crowded freeway, then a single speed setup is
> not really a handicap.
>
>>>> around town driving will be less efficient without the tranny.
>>> In fact, I leave my EV in 2nd gear for almost all around-town
>>> driving, because it's *more* efficient than shifting.
>>
>> Try leaving it in 4th, since that is effectively we are talking
>> about.
>
> No; I think it is a mistake to go transmissionless without also changing
> the differential ratio. My Renault LeCar has a transaxle, so I can't
> change it to a 5:1 ratio and eliminate the transmission. But the
> original poster *can* change his differential to 5:1 and remove the
> transmission. It will be like driving in 3rd gear all the time -- and
> that *does* work for any EV that has a slightly larger motor and
> controller.
>
>> It's easy to win an argument by changing the basic assumptions.
>
> I'm not arguing, Peter. Everything you've said is true; but I believe
> you are giving them too much emphasis. Almost all well designed EVs
> don't use a transmission. There's a reason for that -- they don't *need*
> a transmission if the ratio is chosen right!
> --
> Ring the bells that still can ring
> Forget the perfect offering
> There is a crack in everything
> That's how the light gets in    --    Leonard Cohen
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Victor Tikhonov
In reply to this post by Lee Hart
Lee Hart wrote:
...
> No; I think it is a mistake to go transmissionless without also changing
> the differential ratio. My Renault LeCar has a transaxle, so I can't
> change it to a 5:1 ratio and eliminate the transmission. But the
> original poster *can* change his differential to 5:1 and remove the
> transmission. It will be like driving in 3rd gear all the time -- and
> that *does* work for any EV that has a slightly larger motor and controller.

I did performance simulation for my conversion and came up with
5.7:1 ratio as about optimal compromise between bearings life/diff noise
and torque at the wheels/power at speed. This is single gear
"transmission" set up, e.g. motors run differentials directly.

Anywhere 5.0:1 to 7.0:1 should be fine. 10:1 is OK if you have tiny
wheels and don't mind whining and hot gearbox.

--
Victor
'91 ACRX - something different

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Roland Wiench
In reply to this post by Lee Hart
Hello All,

They finally flatten out one section of road here, in Great Falls, Montana
for about 1000 feet.  So I went to try it with my 7100 lb EV in 3rd gear
with a overall ratio of 5.57:1.

Now I know how all you feel who lives only in the dead flat lands.  Instead
of pulling 300 amps up and 0 amps at 25 mph going down on these roller
coaster roads, I was only pulling 125 to 150 motor amperes and 50 battery
amperes on this stretch.

I came into this section on a slight down hill run at 45 and was able to
maintain that speed at this ampere.

But it takes about 600 amps to start to move this vehicle at a 5.57:1 gear,
so I use a 19.495:1 gear that keeps me below 200 amps.

Roland


----- Original Message -----
From: "Lee Hart" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Tuesday, May 20, 2008 11:46 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion


> Lee Hart wrote:
> >> Essentially all vehicles built as EVs from scratch have no
> >> transmissions (electric cars, trains, buses, golf carts, fork
> >> lifts, etc.)
>
> Peter VanDerWal wrote:
> > We aren't talking about Golf Carts, or even purpose build EVs. We are
> > talking about converting a MUSTANG and connecting the electric motor
> > directly to the differential. In THIS situation, the adverbs apply...
>
> Today, we drove Michael Shoop's Volt Vette (1987 Corvette EV conversion)
> for the first time. It has a Zilla 2K controller, Netgain TransWarP 11"
> motor, 2.73:1 differential, and no transmission. We turned the Zilla
> down to just 250 max battery amps, and 500 max motor amps.
>
> It *still* has plenty of power. Enough, in fact, to climb right over the
> 4" high bump stops on the trailer, and nearly drive into the tow vehicle!
>
> > At 30 mph, the motor is going to be turning at about 1,000 rpm or
> > less (depends on the exact diff ratio)... Assuming a 9" ADC or
> > equivalent, and given the lower voltage needed at 30 mph, this low
> > RPM will only be about 65% efficient
>
> As I said, you want a bigger motor and controller for a transmissionless
> vehicle, and the differential ratio should be significantly increased. A
> 9" motor would be a bit small for an over-3000 lbs transmissionless
> conversion.
>
> The efficiency won't be as bad as 65% unless you don't change the
> differential ratio, and are driving up a hill or accelerating hard so
> motor current is high. Look at the curves for that ADC 9" motor;
> efficiency is over 80% from 10 to 120 ft.lbs of torque and 1000-5000 RPM.
>
> > (not counting the extra power required by the cooling fan)
>
> The external blower for a traction motor uses something like 10 amps at
> 12 volts. That's not much; only a couple percent of total power.
>
> > Assuming you never need to climb hills.  If you do have any hills
> > you'll need closer to 3:1 (i.e the typical difference between 1st/2nd
> > and 4th/5th)
>
> I can't remember any hill steep enough to require me to use 1st gear in
> any of my EVs. Likewise, I've never needed the highest gear (4th or
> 5th), because it slows the motor so far that you don't get adequate
> cooling.
>
> >> Note that you will need to replace your differential gears to go
> >> transmissionless. A typical ICE car differential ratio is around
> >> 3:1. The differential for a transmissionless EV is more like 5:1.
>
> > Or 10:1 as found in many purpose built EVs
>
> Only the ones with 13,000 RPM AC motors.
>
> >>> Also, while electric motors are very efficient over a wide band
> >>> of RPMs, efficiency tends to fall off quickly at very low and
> >>> very high RPMs.
>
> >> Yes; except that your driving time at very low and very high speeds
> >> is generally quite low.
>
> > Unless you drive in traffic.
>
> Hmm... I *do* drive in traffic. In fact, *most* of my EV driving has
> been on residential streets, or crowded freeways with lots of
> stop-and-go traffic. Still, I find that I almost always leave it in one
> gear.
>
> If your driving style is to always accelerate as fast as possible, a
> direct drive EV may not be for you. It would require a much larger motor
> and controller to match the performance you could get with a transmission.
>
> But, if you're talking about normal driving, where acceleration is
> limited by the car ahead of you, or stop signs every block, or
> creep-stop-creep-stop on a crowded freeway, then a single speed setup is
> not really a handicap.
>
> >>> around town driving will be less efficient without the tranny.
> >> In fact, I leave my EV in 2nd gear for almost all around-town
> >> driving, because it's *more* efficient than shifting.
> >
> > Try leaving it in 4th, since that is effectively we are talking
> > about.
>
> No; I think it is a mistake to go transmissionless without also changing
> the differential ratio. My Renault LeCar has a transaxle, so I can't
> change it to a 5:1 ratio and eliminate the transmission. But the
> original poster *can* change his differential to 5:1 and remove the
> transmission. It will be like driving in 3rd gear all the time -- and
> that *does* work for any EV that has a slightly larger motor and
> controller.
>
> > It's easy to win an argument by changing the basic assumptions.
>
> I'm not arguing, Peter. Everything you've said is true; but I believe
> you are giving them too much emphasis. Almost all well designed EVs
> don't use a transmission. There's a reason for that -- they don't *need*
> a transmission if the ratio is chosen right!
> --
> Ring the bells that still can ring
> Forget the perfect offering
> There is a crack in everything
> That's how the light gets in    --    Leonard Cohen
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Roger Stockton
In reply to this post by Lee Hart
Lee Hart wrote:

> Today, we drove Michael Shoop's Volt Vette (1987 Corvette EV
> conversion) for the first time. It has a Zilla 2K controller,
> Netgain TransWarP 11" motor, 2.73:1 differential, and no
> transmission. We turned the Zilla down to just 250 max battery
> amps, and 500 max motor amps.
>
> It *still* has plenty of power.

Now that the issue of whether it might work has been addressed, it might be worthwhile to recall why the question was asked in the first place: I believe the person converting the Mustang mentioned that going transmissionless would save them the cost of an adapter plate.

Cost is NOT an advantage to the transmissionless approach.  Without a transmission, it is advisable to replace the gears in the rear end for at least a 5:1 ratio.  Peter says this will cost a couple of hundred for the gears alone, and not everyone is up to swapping the gears out of a differential and getting them properly shimmed into mesh; figure at least a fewe hundred more if you pay to have the gears swapped professionally.

Without a tranny, the car will require a Transwarp 11 ($3730) and a Z2K-HV ($4675), since I think Peter is correct that a Z2K may be required to ensure that sustained loads in excess of 300A are able to be handled.  Without reverse gear provided by the stock tranny, a reversing contactor such as the Albright SW202B ($570) is required.

Retaining the stock tranny and diff gears, a Warp 9 ($1750) and Z1K-HV ($2675) are all that are required.  The savings of $4700+ vs the transmissionless setup more than covers the cost of the adapter plate, and probably covers most of the cost of a nice pack of AGMs too.  If one wanted even more performance from the transmission-equipped vehicle, one could upgrade the Warp 9 to a Warp 11 ($1275 more than the 9), or the Z1KHV to a Z2K-HV ($2000 more than the Z1K-HV) and still not tilt the cost scale in favour of the transmissionless option.

Indeed, one could upgrade to the Warp 11 AND Z2K and *still* come out ahead with the tranny since the savings on the reversing contactor, diff gears, and difference in cost between the Warp and Transwarp versions of the 11" still more than cover the cost of the adapter plate.

Ditching the tranny does not appear to make sense as a way to reduce the cost of conversion.

Cheers,

Roger.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Mark Eidson
Does this apply to both automatic and manual transmissions?  me

On 5/21/08, Roger Stockton <[hidden email]> wrote:

> Lee Hart wrote:
>
> > Today, we drove Michael Shoop's Volt Vette (1987 Corvette EV
> > conversion) for the first time. It has a Zilla 2K controller,
> > Netgain TransWarP 11" motor, 2.73:1 differential, and no
> > transmission. We turned the Zilla down to just 250 max battery
> > amps, and 500 max motor amps.
> >
> > It *still* has plenty of power.
>
> Now that the issue of whether it might work has been addressed, it might be worthwhile to recall why the question was asked in the first place: I believe the person converting the Mustang mentioned that going transmissionless would save them the cost of an adapter plate.
>
> Cost is NOT an advantage to the transmissionless approach.  Without a transmission, it is advisable to replace the gears in the rear end for at least a 5:1 ratio.  Peter says this will cost a couple of hundred for the gears alone, and not everyone is up to swapping the gears out of a differential and getting them properly shimmed into mesh; figure at least a fewe hundred more if you pay to have the gears swapped professionally.
>
> Without a tranny, the car will require a Transwarp 11 ($3730) and a Z2K-HV ($4675), since I think Peter is correct that a Z2K may be required to ensure that sustained loads in excess of 300A are able to be handled.  Without reverse gear provided by the stock tranny, a reversing contactor such as the Albright SW202B ($570) is required.
>
> Retaining the stock tranny and diff gears, a Warp 9 ($1750) and Z1K-HV ($2675) are all that are required.  The savings of $4700+ vs the transmissionless setup more than covers the cost of the adapter plate, and probably covers most of the cost of a nice pack of AGMs too.  If one wanted even more performance from the transmission-equipped vehicle, one could upgrade the Warp 9 to a Warp 11 ($1275 more than the 9), or the Z1KHV to a Z2K-HV ($2000 more than the Z1K-HV) and still not tilt the cost scale in favour of the transmissionless option.
>
> Indeed, one could upgrade to the Warp 11 AND Z2K and *still* come out ahead with the tranny since the savings on the reversing contactor, diff gears, and difference in cost between the Warp and Transwarp versions of the 11" still more than cover the cost of the adapter plate.
>
> Ditching the tranny does not appear to make sense as a way to reduce the cost of conversion.
>
> Cheers,
>
> Roger.
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Roger Stockton
Mark Eidson wrote:

> Does this apply to both automatic and manual transmissions?  me

The same principle applies, yes.  Going transmissionless will incur the same costs regardless of the nature of the tranny you remove.

However, the cost of keeping an automatic tranny is likely to be greater than that of keeping a manual since most readily available adapters are for manual trannies, and you would also need some means of providing hydraulic pressure for the tranny if you want it to engage and behave similarly as when driven by an ICE.

I thought about this while writing my earlier post, and it occurred to me that the $4700+ savings associated with retaining the tranny is more than enough to make it more econimically viable to replace the automatic tranny with a manual than to ditch the automatic.  This sort of difference in conversion cost is enough for many of us to purchase an entire manual tranny donor vehicle for conversion instead of keeping the automatic or replacing it with a manual.

Cheers,

Roger.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Lee Hart
In reply to this post by Roger Stockton
Roger Stockton wrote:
> Cost is NOT an advantage to the transmissionless approach.

I agree; it is not something you do as an expedient solution in a
conversion, where you already have a perfectly good transmission and
differential.

But, going transmissionless is a good solution in a scratch built EV
(like our Sunrise), or if you don't have a usable transmission and it
could cost thousands of dollars to buy one (like Mike Shoop's Corvette).

> Without a tranny, the car will require a Transwarp 11 ($3730) and a
> Z2K-HV ($4675), since I think Peter is correct that a Z2K may be
> required to ensure that sustained loads in excess of 300A are able to
> be handled.  Without reverse gear provided by the stock tranny, a
> reversing contactor such as the Albright SW202B ($570) is required.

Agreed, if you're going racing. These are some pretty high-powered parts
-- that Mustang would be wickedly fast!

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Lee Hart
In reply to this post by Peter VanDerWal
Peter VanDerWal wrote:
> It's not just about how MUCH torque you can generate, it's about how
> LONG you can generate it.
>
> Assuming a fairly normal conversion of our Mustang (except for the
> missing tranny), even with a 5:1 diff ratio my calculations indicate
> that climbing an 8% hill (pretty common) requires around 400 amps for
> a 9" ADC and around 360 amps with a transwarp 11".

I didn't check the numbers, but that sounds about right.

> The Zilla 1K is only rated for 300 amps continuous.  So unless the
> hill is pretty short, it won't make it up.  If it has to spend more
> than a minute or so climbing it, the maximum hill the 9" ADC & Z1k
> combo can handle is about 5%

I assume you mean an 8% grade (422 feet rise per mile)?

We can ask Otmar, but I'll bet the Z1k can carry 300 amps for a lot more
than 1 minute. Even the lowly Curtis 1221 can do it for 5 minutes. An
ADC 9" motor can carry 300 amps for at least 15 minutes. There are no
hills anywhere near me even remotely high enough to take that long to
climb, even if I drove at 30 mph.

Though of course, others may live in the mountains and routinely drive
up them. Or, I might try to drive in a parade that takes 30 minutes to
climb a steep hill at 3 mph. In these cases, the Z1K and 9" motor would
be inadequate.

> You'd need either the Z2k and a TW 11" or the Z1k and the TW 13" if
> you want to climb some of the steeper, but still common hills (6-10%)
> of any length.

Agreed. That's why we used the Z2K and Transwarp 11" in the Volt Vette.

> I'll grant you my efficiency estimates were off. I had (incorrectly)
> assumed that replacing the ring and pinion gears would be very
> expensive...

You're not too far off. It costs us about $400 parts and labor to
replace the ring and pinion in the Ford 8.8" differential we're using in
the Sunrise.

> It still adds cost to the conversion, but a 5:1 R&P would make it
> doable. Assuming you are willing to shell out the big bucks for the
> oversized motor& controller

Right! If you've already got a transmission you want to use, it's
cheaper to keep it. If you have to *buy* a transmission new, then it's
cheaper to buy a bigger motor and controller instead.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Peter VanDerWal

>> The Zilla 1K is only rated for 300 amps continuous.  So unless the
>> hill is pretty short, it won't make it up.  If it has to spend more
>> than a minute or so climbing it, the maximum hill the 9" ADC & Z1k
>> combo can handle is about 5%
>
> I assume you mean an 8% grade (422 feet rise per mile)?
>
> We can ask Otmar, but I'll bet the Z1k can carry 300 amps for a lot more
> than 1 minute. Even the lowly Curtis 1221 can do it for 5 minutes.

The curtis can do it for 5 minutes when it starts from cold.

I'm sure the Z1k can do it for 5 minutes or more, if IT is cold.  However,
diving around with no tranmission uses a lot of motor amps.  It is quit
likely that the controller will be somewhat warm by the time you start the
hill.  Especially if you have one hill following another (think roller
coaster)

If you live somewhere that doesn't have any hills, it's a moot point.  My
point is that if you live somewhere that DOES have hills, you have to take
the worse case scenario into account.  If you don't then (best case) you
end up stuck on the side of the road waiting for you system to cool off,
or (worse case) you damage something expensive.

Didn't the Sparrow and the Zebra (both light weight, direct drive) have
problems with frying their controllers on hills?

>> You'd need either the Z2k and a TW 11" or the Z1k and the TW 13" if
>> you want to climb some of the steeper, but still common hills (6-10%)
>> of any length.
>
> Agreed. That's why we used the Z2K and Transwarp 11" in the Volt Vette.

Which is more than twice the torque needed for a typical EV with the
transission right?  Isn't that what I originally said?



_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Chuck Homic
Peter VanDerWal wrote:

>> We can ask Otmar, but I'll bet the Z1k can carry 300 amps for a lot more
>> than 1 minute. Even the lowly Curtis 1221 can do it for 5 minutes.
>>    
>
> The curtis can do it for 5 minutes when it starts from cold.
>
> I'm sure the Z1k can do it for 5 minutes or more, if IT is cold.  However,
> diving around with no tranmission uses a lot of motor amps.  It is quit
> likely that the controller will be somewhat warm by the time you start the
> hill.  Especially if you have one hill following another (think roller
> coaster)
>  
The Zilla 1K is rated for 300A continuous based on a coolant temp of 50
degrees C.  (Water cooling is a huge advantage here.)  Further, the
Zilla won't self-destruct.  It will reduce output current to prevent
itself from overheating.  If it were dissipating 5% of that energy (I
highly doubt it), it would be 15A at 144V = ~2KW, which any small
radiator should be able to handle.  I have no doubt the Zilla can push
300A continuously until your tires are bald.  Granted, if I had a
transmission that could cut that current in half, I'd do it in a second!

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Peter VanDerWal
I have no doubt that the Zilla 1k can handle 300 amps continously, as I
pointed out the specs clearly state that it can handle 300 amps
continuously.

The original question is, how long can it handle 400 amps?  How long can
it handle 400 amps when the controller is already warm to start with?

Climbing a 5% grade with a 9" ADC works out to around 300 amps, climbing a
steeper hill will require MORE amps.
Many cities have a lot of hills, some (like San Francisco) have a lot of
steep hills.  It is entirely possible to go up and down multiple hills in
one short trip, or to have to climb a long, fairly steep, hill.
Driving in a city means slower speeds, usually 25-35 mph.

Without a transmission, it requires virtually the same amount of current
to climb a hill at any speed from 10-40mph.  The slower you go up a hill,
the more time you spend on the hill drawing high currents.
Mix a hill with heavy traffic and you easily spend more than a minute or
two on even a short hill.  At 25 mph, it takes almost 2 1/2 minutes just
to go 1 mile.
Going up and down multiple hills can result in having to climb a hill
while the controller is still hot from the previous hill.

I'm not saying this is common, or that everyone needs to worry about it,
just that it's possible.

It's not a simple "if you don't have a transmission you need to be able
produce twice the torque" equation.
Twice the torque requires twice the amps.  All else being equal, twice the
amps equals FOUR TIMES as much waste heat.
Larger controllers/motors can handle more heat, but just because the
motor/controller can produce twice the current, doesn't automatically mean
that it can handle twice the current for twice as long.

Case in point, the Curtis 1231C is rated 500 amps and can handle 225 amps
for 1 hour.  The Z1k is rated 1000 amps, but is only rated for 300 amps
continuous.  For EV purposes 1hr is virtually the same as continuous.
So we have a controller rated for twice the (max) current, but only 1/3
more continuous current.

So, getting back to my original point, climbing steep and/or long hills
without a transmission can require components rated for more than twice
the torque. It could require ones rated for three times the torque or
more.

> Peter VanDerWal wrote:
>>> We can ask Otmar, but I'll bet the Z1k can carry 300 amps for a lot
>>> more
>>> than 1 minute. Even the lowly Curtis 1221 can do it for 5 minutes.
>>>
>>
>> The curtis can do it for 5 minutes when it starts from cold.
>>
>> I'm sure the Z1k can do it for 5 minutes or more, if IT is cold.
>> However,
>> diving around with no tranmission uses a lot of motor amps.  It is quit
>> likely that the controller will be somewhat warm by the time you start
>> the
>> hill.  Especially if you have one hill following another (think roller
>> coaster)
>>
> The Zilla 1K is rated for 300A continuous based on a coolant temp of 50
> degrees C.  (Water cooling is a huge advantage here.)  Further, the
> Zilla won't self-destruct.  It will reduce output current to prevent
> itself from overheating.  If it were dissipating 5% of that energy (I
> highly doubt it), it would be 15A at 144V = ~2KW, which any small
> radiator should be able to handle.  I have no doubt the Zilla can push
> 300A continuously until your tires are bald.  Granted, if I had a
> transmission that could cut that current in half, I'd do it in a second!
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Roger Stockton
In reply to this post by Lee Hart
Lee Hart wrote:

> But, going transmissionless is a good solution in a scratch
> built EV (like our Sunrise),

Absolutely!  I still think you would find that a tranny is cheaper for the Sunrise than paying for a larger motor and controller, and a non-standard gearset for the rear end.  After all, you are building the Sunrise with used drivetrain/brake parts from a T-bird anyway, so including a used 4-speed wouldn't be at all out of place.  Use a tranny compatible with readily available S10 or Ranger adapter plates for convenience.

However, not having the tranny allows the drivetrain weight to be reduced (a slightly larger motor will not be an entire tranny heavier than the smaller one, and the controllers will be virtually the same weight). With an IRS diff going trannyless allows for improved drivetrain configuration (the motor can mount directly or nearly directly to the diff), and this could allow the vehicle to be designed more simply or lighter, or to carry a larger battery pack, etc.

None of these possibilities apply to a FWD vehicle (required diff is integrated with the tranny), nor to most RWD vehicles with live rear axles (mounting the motor to the diff would significantly increase unsprung weight (and would require sufficient clearance for the motor to travel vertically without hitting the body), and connecting it with a driveshaft requires use of a driveshaft similar in length to the original), or for which suitable ratio diff gears aren't available (or aren't economically viable).

> or if you don't have a usable
> transmission and it could cost thousands of dollars to buy
> one (like Mike Shoop's Corvette).

Even in the case of a trannyless 'Vette, it still doesn't seem to make financial sense.  If we agree that a Warp 9 and Z1K-HV would be adequate with a tranny, then my shopping revealed a $4700+ premium for the TransWarp 11 + Z2K-HV, diff gears, etc. for the trannyless option.  That assumed only $200 for the new diff gearset, so crank the difference up to about $5k given that it actually cost $400 for the gearset for the 'Vette.

If the 'Vette doesn't have a tranny at present, then *any* suitable Chevy or Ford, etc. tranny could be used.  No need to fork out big bucks for a 'Vette specific 5 or 6 speed when we know the EV is likely to use only a couple of gears anyway.  Even if one went with a 'Vette specific tranny, it looks like a complete *new* tranny could be had for about $3200, and most people would probably buy one from a wrecker for considerably less:

<http://www.classicchevy5speed.com/Deluxe-Corvette-1984-88-Ultimate-Fit-Tremec.aspx>

$3200 for a brand new 'Vette 5-speed + the cost of an adapter plate looks like it would still come out about even in cost with the trannyless approach.

> > Without a tranny, the car will require a Transwarp 11 ($3730) and a
> > Z2K-HV ($4675), since I think Peter is correct that a Z2K may be
> > required to ensure that sustained loads in excess of 300A
> > are able to be handled.  Without reverse gear provided by the stock
> > tranny, a reversing contactor such as the Albright SW202B ($570) is required.
>
> Agreed, if you're going racing. These are some pretty
> high-powered parts -- that Mustang would be wickedly fast!

Well, why on earth would someone convert a sportscar into an EV with econobox performance? ;^>

Is your friend going racing with his 'Vette?

More seriously, I suggested the 11" because that is what your friend used in his 'Vette, and because it is generally accepted that a 9" is about adequate (but not excessive) for a 3000-4000lb conversion with a tranny, so something larger would be required without a tranny.

The Z2K-HV is again both because your friend used a Z2K, and because I agree with Peter that in general the Z1K might not be able to provide the required continuous current once warm.  The -HV is because Otmar appears to have streamlined his offerings and no longer lists any other Z2K models.

I suspect that if one went with a pair of 9's (e.g one Transwarp and one Warp) that a Z1K with series/parallel would be adequate in a trannyless (heavy) sportscar.  It would probably be cheaper overall than a TW11 and Z2K.  I haven't looked up the specs to verify it, but I expect the 11" probably delivers less than 2x the torque per amp of a 9", and so a pair of 9's could get the same torque to the rear end with fewer amps from the controller.

Cheers,

Roger.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Adrian DeLeon
In reply to this post by chazersize
> The Zilla 1K is rated for 300A continuous based on a coolant temp of 50
> degrees C.

Actually, it's rated for "greater than 350A continuous" @50C coolant temp.

I live in a hilly area and have pulled >400A for over a minute at the end  
of a 5 mile run. I have a tiny PC water cooling radiator and have NEVER  
had any thermal cutback. With a decent radiator, I'd bet you could get  
450-500A for several minutes.

-Adrian

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Roger Stockton
Adrian DeLeon wrote:

> > The Zilla 1K is rated for 300A continuous based on a
> > coolant temp of 50 degrees C.
>
> Actually, it's rated for "greater than 350A continuous" @50C
> coolant temp.

Seems to depend where you look ;^>

In the manual it says "Continuous motor current @ 50°C coolant temp & 100% Duty Cycle:
over 700 Amps for Z2K, over 350 Amps for Z1K".

On the website it says "Continuous motor current @ 50°C coolant temp & 100% Duty Cycle: over 600 Amps for Z2K, 300 Amps for Z1K".

The "& 100% Duty Cycle" may also be an important qualifier.

"300" or "350" could be a simple typo, but the accompanying "600" and "700" confirm it to be deliberate.  The only question is were the original ratings conservative and have they later been upgraded in the manual, or were they originally optimistic and have been downgraded on the webpage but not the manual?  Or, has there been a change in production such that units produced before some point have one rating and those after have the other?

> I live in a hilly area and have pulled >400A for over a
> minute at the end of a 5 mile run. I have a tiny PC water
> cooling radiator and have NEVER had any thermal cutback.

This is certainly reassuring news.  What sort of EV do you have (weight, voltage, etc.)?  If you have a tranny, how much more than that >400A would you need to pull if you had no tranny (i.e. if you were driving in 3rd or 4th gear)?

> With
> a decent radiator, I'd bet you could get 450-500A for several minutes.

I suspect it will depend greatly on what you were doing before those minutes and how warm it is outside.  50C isn't very far from air temp on a hot day (30-35C), so it could take a fairly serious radiator, pump, and maybe a fan to keep the coolant below 50C.

Cheers,

Roger.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Lee Hart
In reply to this post by Roger Stockton
Roger Stockton wrote:
> I still think you would find that a tranny is cheaper for the Sunrise
> than paying for a larger motor and controller, and a non-standard
> gearset for the rear end.

We considered it; but the Sunrise is designed to be an EV; there isn't
any place for a transmission. The batteries occupy the entire central
tunnel, where a transmission would normally go.

We could remove batteries to make room for a transmission; but that
reduces range. A transmission would also force us back to either a front
wheel drive layout, with the batteries (and thus most of the weight) in
the back. Or, if we stayed with the rear wheel drive layout (to keep the
batteries farther forward, for normal handling) the entire central
tunnel would be filled with the motor, transmission, and drive shaft.

The car we are using as a donor only comes with a large heavy automatic
transmission. It doesn't have a locking torque converter, and is heavier
than the motor itself, and so a poor choice for an EV.

We're using a WarP 9" motor, which is no bigger than what most EV
conversions use. Rather than upsizing the motor, we're downsizing the
car. The Sunrise EV2 is considerably lighter than a regular car.

Replacement 5:1 gears are under $200. This differential is popular for
racing, so gearsets are readily available.

> However, not having the tranny allows the drivetrain weight to be
> reduced

Right. A larger motor does not weigh as much as a smaller motor plus
transmission.

> With an IRS diff going trannyless allows for improved drivetrain
> configuration (the motor can mount directly or nearly
> directly to the diff), and this could allow the vehicle to be
> designed more simply or lighter, or to carry a larger battery pack,
> etc.

Exactly! Our motor mounts straight to the differential, with no
driveshaft, universal joints, adapter plate, motor mounts, or other
heavy expensive parts found in EV conversions.

> Even in the case of a trannyless 'Vette, it still doesn't seem to
> make financial sense.

No; we didn't go transmissionless to save money. We did it because
there's so little room for batteries. Eliminating the transmission
allows the motor to be moved rearward, freeing the underhood area for
more batteries.

> If the 'Vette doesn't have a tranny at present, then *any* suitable
> Chevy or Ford, etc. tranny could be used.  No need to fork out big
> bucks for a 'Vette specific 5 or 6 speed when we know the EV is
> likely to use only a couple of gears anyway.

The Corvette has a unique engine, transmission, and differential layout.
None of them are interchangeable with any other GM vehicles. The 'Vette
manual transmission is stupefyingly expensive. Michael saved over $2000
by buying one with an automatic transmission.

One snag we didn't foresee; 'Vette's come with two different Dana
differentials. One of them is easy to get other gearsets for; the other
one has a very limited selection. Naturally, Michael's has the wrong
one. Thus, we're stuck with the 2.73:1 ratio until we can find the other
differential.

> Is your friend going racing with his 'Vette?

Probably not. But he does want it to have "impressive" performance.

> I suspect that if one went with a pair of 9's (e.g one Transwarp and
> one Warp) that a Z1K with series/parallel would be adequate in a
> trannyless (heavy) sportscar.

Yes; that's another option that might work out well.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Tim Medeck
In reply to this post by Roger Stockton
Tim Medeck here,
 
The Sunrise is in my shop, and Shoop's Vette just left the shop under it's own power a couple of days ago. > Lee Hart wrote:> > > But, going transmissionless is a good solution in a scratch> > built EV (like our Sunrise),
Roger wrote:> Absolutely! I still think you would find that a tranny is cheaper for the Sunrise than paying for a larger motor and controller, and a non-standard gearset for the rear end. After all, you are building the Sunrise with used drivetrain/brake parts from a T-bird anyway, so including a used 4-speed wouldn't be at all out of place. Use a tranny compatible with readily available S10 or Ranger adapter plates for convenience.
There is no room for a transmission in the Sunrise-EV2. With the central battery tunnel, and the differential rotated 180 degrees so the motor points toward the rear of the car, it is still a tight squeeze to get everything crammed in the available space.
> However, not having the tranny allows the drivetrain weight to be reduced (a slightly larger motor will not be an entire tranny heavier than the smaller one, and the controllers will be virtually the same weight). With an IRS diff going trannyless allows for improved drivetrain configuration (the motor can mount directly or nearly directly to the diff), and this could allow the vehicle to be designed more simply or lighter, or to carry a larger battery pack, etc.
 
Exactly. The only thing between the motor and the differential is a Lovejoy coupling, so it is as short as possible.
 > Even in the case of a trannyless 'Vette, it still doesn't seem to make financial sense. If we agree that a Warp 9 and Z1K-HV would be adequate with a tranny, then my shopping revealed a $4700+ premium for the TransWarp 11 + Z2K-HV, diff gears, etc. for the trannyless option. That assumed only $200 for the new diff gearset, so crank the difference up to about $5k given that it actually cost $400 for the gearset for the 'Vette.> > If the 'Vette doesn't have a tranny at present, then *any* suitable Chevy or Ford, etc. tranny could be used. No need to fork out big bucks for a 'Vette specific 5 or 6 speed when we know the EV is likely to use only a couple of gears anyway. Even if one went with a 'Vette specific tranny, it looks like a complete *new* tranny could be had for about $3200, and most people would probably buy one from a wrecker for considerably less:
Again, space is the problem. The Vette's Transwarp 11 is mounted where the automatic transmission used to be, and a battery box is where the ICE used to be. If he put a transmission in the car, the motor would be where the "middle" battery box is and he'd have to find a new spot to put those batteries. (Not easy in a C4 Corvette)
 > $3200 for a brand new 'Vette 5-speed + the cost of an adapter plate looks like it would still come out about even in cost with the trannyless approach.
 
Yeah, but cost is not the sticking point. SPACE for the parts is the problem.
> Well, why on earth would someone convert a sportscar into an EV with econobox performance? ;^>
 
Michael is building this car to promote EVs. He is going to take it to a lot of "Green" shows and even Corvette shows and meets. He is willing to sacrifice driving range so that he can present an EV to the public that is NOT a cheese wedge or econobox . After he gets a 4:88 (or there about) gear set in the differential, the car will light up the tires at will. This is his choice and I think that he should applauded for it, not vilified. (Nothing against you, Roger, you're bringing up points that need to be addressed) Lee and I tuned the Zilla down to 50 volts and 250 amps in reverse, and it STILL  surprised us with it's power backing on to the car dolly!
 
> I suspect that if one went with a pair of 9's (e.g one Transwarp and one Warp) that a Z1K with series/parallel would be adequate in a trannyless (heavy) sportscar. It would probably be cheaper overall than a TW11 and Z2K. I haven't looked up the specs to verify it, but I expect the 11" probably delivers less than 2x the torque per amp of a 9", and so a pair of 9's could get the same torque to the rear end with fewer amps from the controller.
 
Again, space is the issue. With conversions, or even scratch built  EVs ,it comes down to space, space, space. (Not to mention money . . . money . . . money) We all know and agree that if we could get our hands on the  Nimh batteries that the original Sunrise used, our lives would be a lot easier. But, like Lee Hart has said many times . . . we have to work with what we've got. (And Bob Rice has said . . . WE 'RE DEALING WITH OLD CRAP TECHNOLOGY LEAD ACID BATTERIES THAT SUCK!)
 
 So, we do what we can do with what we have and try our best to put good product on the road. (At least, that's what I'm shooting for)
 
For what it's worth,
 
Tim
 
 
 
 
 
 
 
 
 
 
Tim
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no tranny for conversion

Lee Hart
Tim Medeck wrote:

Looks good, Tim! I don't have any disagreements with anything you said.
You also made some good points on why Michael is converting such an
unusual vehicle as a Corvette.

> Tim Medeck here,
>  
> The Sunrise is in my shop, and Shoop's Vette just left the shop under it's own power a couple of days ago. > Lee Hart wrote:> > > But, going transmissionless is a good solution in a scratch> > built EV (like our Sunrise),
> Roger wrote:> Absolutely! I still think you would find that a tranny is cheaper for the Sunrise than paying for a larger motor and controller, and a non-standard gearset for the rear end. After all, you are building the Sunrise with used drivetrain/brake parts from a T-bird anyway, so including a used 4-speed wouldn't be at all out of place. Use a tranny compatible with readily available S10 or Ranger adapter plates for convenience.
> There is no room for a transmission in the Sunrise-EV2. With the central battery tunnel, and the differential rotated 180 degrees so the motor points toward the rear of the car, it is still a tight squeeze to get everything crammed in the available space.
>> However, not having the tranny allows the drivetrain weight to be reduced (a slightly larger motor will not be an entire tranny heavier than the smaller one, and the controllers will be virtually the same weight). With an IRS diff going trannyless allows for improved drivetrain configuration (the motor can mount directly or nearly directly to the diff), and this could allow the vehicle to be designed more simply or lighter, or to carry a larger battery pack, etc.
>  
> Exactly. The only thing between the motor and the differential is a Lovejoy coupling, so it is as short as possible.
>  > Even in the case of a trannyless 'Vette, it still doesn't seem to make financial sense. If we agree that a Warp 9 and Z1K-HV would be adequate with a tranny, then my shopping revealed a $4700+ premium for the TransWarp 11 + Z2K-HV, diff gears, etc. for the trannyless option. That assumed only $200 for the new diff gearset, so crank the difference up to about $5k given that it actually cost $400 for the gearset for the 'Vette.> > If the 'Vette doesn't have a tranny at present, then *any* suitable Chevy or Ford, etc. tranny could be used. No need to fork out big bucks for a 'Vette specific 5 or 6 speed when we know the EV is likely to use only a couple of gears anyway. Even if one went with a 'Vette specific tranny, it looks like a complete *new* tranny could be had for about $3200, and most people would probably buy one from a wrecker for considerably less:
> Again, space is the problem. The Vette's Transwarp 11 is mounted where the automatic transmission used to be, and a battery box is where the ICE used to be. If he put a transmission in the car, the motor would be where the "middle" battery box is and he'd have to find a new spot to put those batteries. (Not easy in a C4 Corvette)
>  > $3200 for a brand new 'Vette 5-speed + the cost of an adapter plate looks like it would still come out about even in cost with the trannyless approach.
>  
> Yeah, but cost is not the sticking point. SPACE for the parts is the problem.
>> Well, why on earth would someone convert a sportscar into an EV with econobox performance? ;^>
>  
> Michael is building this car to promote EVs. He is going to take it to a lot of "Green" shows and even Corvette shows and meets. He is willing to sacrifice driving range so that he can present an EV to the public that is NOT a cheese wedge or econobox . After he gets a 4:88 (or there about) gear set in the differential, the car will light up the tires at will. This is his choice and I think that he should applauded for it, not vilified. (Nothing against you, Roger, you're bringing up points that need to be addressed) Lee and I tuned the Zilla down to 50 volts and 250 amps in reverse, and it STILL  surprised us with it's power backing on to the car dolly!
>  
>> I suspect that if one went with a pair of 9's (e.g one Transwarp and one Warp) that a Z1K with series/parallel would be adequate in a trannyless (heavy) sportscar. It would probably be cheaper overall than a TW11 and Z2K. I haven't looked up the specs to verify it, but I expect the 11" probably delivers less than 2x the torque per amp of a 9", and so a pair of 9's could get the same torque to the rear end with fewer amps from the controller.
>  
> Again, space is the issue. With conversions, or even scratch built  EVs ,it comes down to space, space, space. (Not to mention money . . . money . . . money) We all know and agree that if we could get our hands on the  Nimh batteries that the original Sunrise used, our lives would be a lot easier. But, like Lee Hart has said many times . . . we have to work with what we've got. (And Bob Rice has said . . . WE 'RE DEALING WITH OLD CRAP TECHNOLOGY LEAD ACID BATTERIES THAT SUCK!)
>  
>  So, we do what we can do with what we have and try our best to put good product on the road. (At least, that's what I'm shooting for)
>  
> For what it's worth,
>  
> Tim
>  
>  
>  
>  
>  
>  
>  
>  


--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor with no transmission for conversion

Mark Grasser
In reply to this post by Lee Hart
Lee,
Not to keep pushing the transmission idea but did you consider a transaxle,
granted a little more expensive than your usual transmission but uses barely
any extra space. Porsche 944 and 928, the new corvettes also have them. Did
you consider mounting any of the front wheel drive transmissions in the rear
of the car?

Mark Grasser
 

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf
Of Lee Hart
Sent: Thursday, May 22, 2008 10:32 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Electric motor with no tranny for conversion

Roger Stockton wrote:
> I still think you would find that a tranny is cheaper for the Sunrise
> than paying for a larger motor and controller, and a non-standard
> gearset for the rear end.

We considered it; but the Sunrise is designed to be an EV; there isn't
any place for a transmission. The batteries occupy the entire central
tunnel, where a transmission would normally go.

We could remove batteries to make room for a transmission; but that
reduces range. A transmission would also force us back to either a front
wheel drive layout, with the batteries (and thus most of the weight) in
the back. Or, if we stayed with the rear wheel drive layout (to keep the
batteries farther forward, for normal handling) the entire central
tunnel would be filled with the motor, transmission, and drive shaft.

The car we are using as a donor only comes with a large heavy automatic
transmission. It doesn't have a locking torque converter, and is heavier
than the motor itself, and so a poor choice for an EV.

We're using a WarP 9" motor, which is no bigger than what most EV
conversions use. Rather than upsizing the motor, we're downsizing the
car. The Sunrise EV2 is considerably lighter than a regular car.

Replacement 5:1 gears are under $200. This differential is popular for
racing, so gearsets are readily available.

> However, not having the tranny allows the drivetrain weight to be
> reduced

Right. A larger motor does not weigh as much as a smaller motor plus
transmission.

> With an IRS diff going trannyless allows for improved drivetrain
> configuration (the motor can mount directly or nearly
> directly to the diff), and this could allow the vehicle to be
> designed more simply or lighter, or to carry a larger battery pack,
> etc.

Exactly! Our motor mounts straight to the differential, with no
driveshaft, universal joints, adapter plate, motor mounts, or other
heavy expensive parts found in EV conversions.

> Even in the case of a trannyless 'Vette, it still doesn't seem to
> make financial sense.

No; we didn't go transmissionless to save money. We did it because
there's so little room for batteries. Eliminating the transmission
allows the motor to be moved rearward, freeing the underhood area for
more batteries.

> If the 'Vette doesn't have a tranny at present, then *any* suitable
> Chevy or Ford, etc. tranny could be used.  No need to fork out big
> bucks for a 'Vette specific 5 or 6 speed when we know the EV is
> likely to use only a couple of gears anyway.

The Corvette has a unique engine, transmission, and differential layout.
None of them are interchangeable with any other GM vehicles. The 'Vette
manual transmission is stupefyingly expensive. Michael saved over $2000
by buying one with an automatic transmission.

One snag we didn't foresee; 'Vette's come with two different Dana
differentials. One of them is easy to get other gearsets for; the other
one has a very limited selection. Naturally, Michael's has the wrong
one. Thus, we're stuck with the 2.73:1 ratio until we can find the other
differential.

> Is your friend going racing with his 'Vette?

Probably not. But he does want it to have "impressive" performance.

> I suspect that if one went with a pair of 9's (e.g one Transwarp and
> one Warp) that a Z1K with series/parallel would be adequate in a
> trannyless (heavy) sportscar.

Yes; that's another option that might work out well.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
Reply | Threaded
Open this post in threaded view
|

Re: Electric motor hybred something.

Roland Wiench

Did you consider mounting any of the front wheel drive transmissions in the
rear of the car?

Mark Grasser


Just about did this method back in 1985 before I experiment with a with a
v-6 engine that can drive the vehicle either by itself, or as a helper to
the electric motor or electric power only.  The engine was place in front of
a GE-11 motor which was couple to the input shaft of the motor with a In and
Out clutch.

It work great for climbing these mountain roads, but city driving not so
great, because the average mpg drop and using it as a electric only, the
range was cut in half because of the weight.

So I came across a front wheel drive Buick with only 900 miles on it that
the rear of the vehicle was gone.  I was thinking of getting another new
front wheel drive Buick and connect the two back to back.

Have one driven by electric and the other end driven by the engine. I Either
one can become a helper while the other becomes the prime mover.

We had one guy did this with two Chevy pickups, but left the engines in
place and the driving direction is forward either in either direction,
having two steering wheels, controls and etc. Had the two boxes connected
together at the tail gate for a very large cargo space.

Now if I did that, I could get 80 batteries in there and use two 13 inchers
and to get over the rocks.

Roland


 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
12345