Wanted: More Amps

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Wanted: More Amps

drdhdmd
In my present set up with a Zilla Z1K -HV and 13 Deka 12V - 100AH  
(advertised at 1000 crank amps) I seem to only be able to only  get 700 - 800 amps
maximum current.  What can I do to locate the  problem?
 
If I want short bursts of higher current, (say ~1600 Amps for 10 seconds at  
a time), could I add 1 battery to make it an even 14, then have "series /  
paralleling contactors" to split the pack into two strings of 7 batteries and  
then put those batteries in parallel?  Then to control that high current,  use
my 2400 Amp IGBT?
 
How would the Zilla react to all this?
 
Where can I get contactors rated at 2000 amps?
 
Dave Delman
Electric DeLorean Project
electricdelorean.com



**************Start the year off right.  Easy ways to stay in shape.    
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Re: Wanted: More Amps

Roland Wiench
Hello Dave,

I am using the Cableform industrial open frame DC contactors that are design
for traction motors.  The A1200 contactor is rated for 300 amp continuous
and 400 amp by adding double braid on the moving contacts.

This contactor is rated for 2000 amps rupturing capability at 242 volts.

I am using line voltage coils instead of 12 volt coils, which the coil
rating is design at the battery pack voltage and if you have a very deep
battery sag cause by a lock on controller, these contactors will drop off
line.

Of course if you a drag racing, you may not want this feature where you go
till something blows up.

See at: http://www.cableform.com/t1/tp/dcce-a1200-htm

It would be best to contact Richard at [hidden email]
for data on this contactor.

You can just type Cableform A1200 contactor in your search engine and page
down on the web addresses to see comments by Otmar and others of this
contactor.

Roland


----- Original Message -----
From: <[hidden email]>
To: <[hidden email]>
Sent: Sunday, January 06, 2008 6:47 AM
Subject: [EVDL] Wanted: More Amps


> In my present set up with a Zilla Z1K -HV and 13 Deka 12V - 100AH
> (advertised at 1000 crank amps) I seem to only be able to only  get 700 -
> 800 amps
> maximum current.  What can I do to locate the  problem?
>
> If I want short bursts of higher current, (say ~1600 Amps for 10 seconds
> at
> a time), could I add 1 battery to make it an even 14, then have "series /
> paralleling contactors" to split the pack into two strings of 7 batteries
> and
> then put those batteries in parallel?  Then to control that high current,
> use
> my 2400 Amp IGBT?
>
> How would the Zilla react to all this?
>
> Where can I get contactors rated at 2000 amps?
>
> Dave Delman
> Electric DeLorean Project
> electricdelorean.com
>
>
>
> **************Start the year off right.  Easy ways to stay in shape.
> http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Re: Wanted: More Amps

Zeke Yewdall
If you have a zilla, why not leave the batteries in series all the
time -- if they are two strings in parallel, the current per battery
would be half, and thus the effects of internal resistance would be
less -- except that the zilla will be trying to draw twice the total
battery current in order to drive the same peak motor current -- so it
doesn't help.

Do you know what the battery current is when the motor current gets to
800A ?  Probaby only 200 or 300A?

Z

On Jan 6, 2008 9:45 AM, Roland Wiench <[hidden email]> wrote:

> Hello Dave,
>
> I am using the Cableform industrial open frame DC contactors that are design
> for traction motors.  The A1200 contactor is rated for 300 amp continuous
> and 400 amp by adding double braid on the moving contacts.
>
> This contactor is rated for 2000 amps rupturing capability at 242 volts.
>
> I am using line voltage coils instead of 12 volt coils, which the coil
> rating is design at the battery pack voltage and if you have a very deep
> battery sag cause by a lock on controller, these contactors will drop off
> line.
>
> Of course if you a drag racing, you may not want this feature where you go
> till something blows up.
>
> See at: http://www.cableform.com/t1/tp/dcce-a1200-htm
>
> It would be best to contact Richard at [hidden email]
> for data on this contactor.
>
> You can just type Cableform A1200 contactor in your search engine and page
> down on the web addresses to see comments by Otmar and others of this
> contactor.
>
> Roland
>
>
>
> ----- Original Message -----
> From: <[hidden email]>
> To: <[hidden email]>
> Sent: Sunday, January 06, 2008 6:47 AM
> Subject: [EVDL] Wanted: More Amps
>
>
> > In my present set up with a Zilla Z1K -HV and 13 Deka 12V - 100AH
> > (advertised at 1000 crank amps) I seem to only be able to only  get 700 -
> > 800 amps
> > maximum current.  What can I do to locate the  problem?
> >
> > If I want short bursts of higher current, (say ~1600 Amps for 10 seconds
> > at
> > a time), could I add 1 battery to make it an even 14, then have "series /
> > paralleling contactors" to split the pack into two strings of 7 batteries
> > and
> > then put those batteries in parallel?  Then to control that high current,
> > use
> > my 2400 Amp IGBT?
> >
> > How would the Zilla react to all this?
> >
> > Where can I get contactors rated at 2000 amps?
> >
> > Dave Delman
> > Electric DeLorean Project
> > electricdelorean.com
> >
> >
> >
> > **************Start the year off right.  Easy ways to stay in shape.
> > http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Re: Wanted: More Amps

Roderick Wilde
In reply to this post by drdhdmd
  Hi Dave, can you tell us where you are reading your 700-800 amps Are these
battery amps or motor amps? This makes a big difference. Are you familiar
with the basic idea of how a controller works? It basically works similar to
a transformer. When you first take off the mosfets or IGBTs chop the voltage
into an and off time. If the on time is 25% then the motor only "sees" 25%
of the voltage and therefore only turns 25% of the RPMs. This is how speed
is controlled. When you take first off the controller is swapping volts for
amps. Your motor will "see" high amps to get it moving but it will only
"see" low volts. For example if you had a 100 volt system with a 500 amp
controller and you first take off your motor might be seeing 500 amps at 10
volts but your batteries are only having 50 amps drawn out of them and are
still near 100 volts. Watts in equals watts out minus inefficiencies. Some
other factors occur as you continue to accelerate. The amps being drawn from
the batteries increases and causes their voltage to drop due to voltage sag.
The voltage the motor "sees" increases and the RPMs increase. As you
accelerate you will feel the motor pulling less hard all the time. This is
because the motor acts both as a motor and a generator. It creates back emf
. When the amps coming from the batteries is nearly equal to the amps being
delivered to the motor you have reached this state of back emf . To make a
motor "want" to have this state at a higher RPM you increase your voltage.
This makes the motor "want" to draw more amps and draw them longer. In
racing we sometimes double or triple name plate voltage. This makes the
state of back emf so far out there that the motor will "try" to reach it but
never will of course, unless you miss a shift without a rev limiter, because
the extreme RPMs would cause all the commutaor bars to grenade. I know this
from actual experiences :-)

  Back to your problem, maybe you already understood how the controller
functions but there are many new people on the list who may not so I wrote
it anyway. If you are reading 700-800 battery amps this may be because of a
combination of the weight of your car, the gear ratio, and your voltage. You
say you want bursts of 1600 amps for 10 seconds. First of all I really doubt
that your batteries could put out that much current at all let alone for 10
seconds. An Optima Yellow Top with very low internal resistance could only
put out 1400 amps. The amazing Excide XCD (Extreme Cycle Duty) battery would
put out an amazing 2000 amps. These are the ones we used in "Gone Postal". A
battery puts out it's maximum horsepower when it is near half voltage sag
due to the amp draw. At the maximum horsepower of your batteries you would
only be delivering around 80 volts from them. 80 volts will not make a car
accelerate to any great speed. If you try to suck more amps out of your
batteries then they can take they just blow up. Ask John Wayland if you
don't believe me.

   I could not find where you mention which specific Deka AGM battery you
are using but I would assume it is their Intimidator model. It does have the
specs you have stated. These type of batteries are what I call cross dresser
batteries :-) They try to be both a deep cycle battery and a cranking
batter. In order to do this they give up something on both ends. As a deep
cycle they do not have very much cycle life when used in these applications.
I think the most life I have heard of is about two years. They are sealed
and therefore require some form of battery management. Without it their time
on this earth is even more limited.

  Dave I read your great posts on Milestones with your car. I could not find
these on your web site. If they are not there you should definitely include
them. Also adding one more battery to your string will increase your top
speed and performance, for reasons given above, as well as give you a little
more range. It is a win, win, situation. Do it soon before your current
batteries have very many cycles or you will have an out of balance pack.

Roderick Wilde, President
EV Parts Inc.



----- Original Message -----
From: <[hidden email]>
To: <[hidden email]>
Sent: Sunday, January 06, 2008 5:47 AM
Subject: [EVDL] Wanted: More Amps


> In my present set up with a Zilla Z1K -HV and 13 Deka 12V - 100AH
> (advertised at 1000 crank amps) I seem to only be able to only  get 700 -
> 800 amps
> maximum current.  What can I do to locate the  problem?
>
> If I want short bursts of higher current, (say ~1600 Amps for 10 seconds
> at
> a time), could I add 1 battery to make it an even 14, then have "series /
> paralleling contactors" to split the pack into two strings of 7 batteries
> and
> then put those batteries in parallel?  Then to control that high current,
> use
> my 2400 Amp IGBT?
>
> How would the Zilla react to all this?
>
> Where can I get contactors rated at 2000 amps?
>
> Dave Delman
> Electric DeLorean Project
> electricdelorean.com
>
>
>
> **************Start the year off right.  Easy ways to stay in shape.
> http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.516 / Virus Database: 269.17.13/1210 - Release Date: 1/5/2008
> 11:46 AM
>
>

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Re: Wanted: More Amps

Adrian DeLeon
In reply to this post by drdhdmd
> In my present set up with a Zilla Z1K -HV and 13 Deka 12V
> If I want short bursts of higher current, could I add
> 1 battery to make it an even 14...

If it's really a Z1K -HV then just add the extra battery. The -HV is good  
to 300V input. You won't get any more amps out of the batteries, but  
you'll have 12V x 700A = 8.4kW more power on tap.

If you have a Z1K -LV then:

1) Find beefier batteries
2) Add a 2nd string of batteries in parallel to the 1st (switch to 50AH  
batteries that will handle 800A each)
3) Find each battery a buddy (pair)

Keep in mind the Z1K will "only" put 1000A to the motor, and not for long  
periods of time. If you're measuring 700-800 battery amps then you MAY be  
in current limit. In this case the only solution is a Z2K. Have a look at  
Mike Willmon's FastTrack results for 0-60MPH in 3rd gear only:

http://home.gci.net/~saintbernard

Full throttle all the way. Motor amps are pegged at 1000A for about 8  
seconds. Battery amps climb steadily until battery amps = motor amps, then  
both decline steadily to about 600A over the next 7 seconds. The decline  
is due to back EMF making it harder for the batteries to push current  
through the motor. It's also possible the controller is cutting back on  
amps as it heats up (Z1K is 350A continuous).

-Adrian

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