[ausev] power pull

[Kevin Douglass]

Mark,

I'm planning on using Deka Absorbed Glass Mat group 31 batteries.

I have the spec sheet on the batteries.  The Ampere Hour Capacity chart has
several columns.  Which one do I read to compare to your 140Ah number.  The
one hour number is 68.  These sealed batteries don't have the range of the
wet cells but I don't need much more than 20 miles between charges and I
don't want to deal with the maintenance and cleanup of them.  I'm also
trying to use the same system as the Solectria Force to see how it compares
using a manual transmission.

Thanks for your comments and this forum.  You guys are very knowledgeable
and informative.

Kevin Douglass
Houston EAA (HEAA)

-----Original Message-----
From: ausev-bounces at austinev.org [mailto:ausev-bounces at austinev.org] On
Behalf Of Marc Kohler
Sent: Wednesday, January 28, 2009 4:21 PM
To: 'AustinEV News Announcements and General Discussion'
Subject: Re: [ausev] power pull

Kevin, how big are your 12V batteries?  If they are 140Ah versions, that's
over 22kWh (nameplate, not useable).
Regen might make up the difference to have the same range as Brian.
I don't think you will be able to accelerate as fast as Brian's car if you
chose the smaller AC24 motor.
Marc Kohler

-----Original Message-----
From: ausev-bounces at austinev.org [mailto:ausev-bounces at austinev.org] On
Behalf Of Brian Lasseter
Sent: Wednesday, January 28, 2009 3:53 PM
To: AustinEV News Announcements and General Discussion
Subject: Re: [ausev] power pull

On Wed, Jan 28, 2009 at 12:37 PM, Kevin Douglass
<k.douglass at earthlink.net> wrote:
> I'm converting an old Honda Accord Hatchback that will weigh about 2800
when
> I'm done.  I'm using the Electro Automotive A/C kit and 13 sealed lead
acid
> 12v batteries.  For comparison and my own expectations on performance:

13x 12V batteries seems a bit small for a 2800 lb car,  I run 18x 8V
batteries (or 24.4 kwh of flooded lead acid), and I have troubles
keeping to a 45 mile range if I'm running enough errands.  (Or if it's
cold enough... My range is just about cut in half at 40F.)


> What kind of car do you have?

2002 Saturn SL, with a manual transmission.  I have photos posted on
my site:
http://www.lasso-jenn.com/photos/2008-04-05%20%20Finishing%20up%20the%20elec
tric%20car/?d=c&img=6


> What motor/controller does it use?

I use an Advanced DC FB1-4001A motor with a Zilla-1K controller.


> What gear do you use at 70 mph and what is the rpm of your motor at that
> speed?

I usually use 3rd gear at 70mph.  I can't accelerate too fast in that
gear at that speed.  If I find I need to maneuver around traffic, I
will go to 4th gear.

The tire calculator http://www.discounttire.com/dtcs/infoTireMath.dos
says that my P185/65R15 tires get 824.25 revs/mile.

824.25 revs/mile * 70 mile/hr / 60 min/hr = 961.625 revs/min

I don't have my service manual... but online I found a 2002 Saturn SL
(with an automatic trans) that had the following ratios:

  First Gear Ratio (:1) 2.526
  Second Gear Ratio (:1) 1.556
  Third Gear Ratio (:1) 1.030
  Fourth Gear Rato (:1) 0.700
  Reverse Ratio (:1) 1.905
  Final Drive Axle Ratio (:1) 4.060

So multiplying 961.625 rpms at the wheel times the final and third
gear ratio gives me 4021.3 rpms in 3rd gear at 70mph.  I think that
math is correct, and 4021.3 rpms seems to be an appropriate number at
that speed in that gear.


-- 
TTFN,
Brian "Lasso" Lasseter


"No Sane man will dance."   -Cicero (106-43 B.C.)
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