[ausev] power pull

[Brian Lasseter]

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%20electric%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.)