[ausev] GE 11.5 inch motor

[Chris Robison]

Brian Lasseter wrote:
> On Jan 2, 2008 3:59 PM, loopcat <loopcat at yahoo.com> wrote:
>> Great! Now it's time to find a good donor car. I'm
>> leaning towards a BMW/saab/volvo station wagon. That
>> should give enough space and strength for the
>> batteries. I thinking that a compact car might be too
>> small for this motor. Any thoughts on a good
>> make/model?
> 
> Eek... A BMW, or saab, or volvo?  Really the curb weight of the
> vehicle should be a main buying factor.  BMW's, Saab's, and Volvo's
> are all very heavy, at least 3000 pounds.   Light cars are a must...
> finding a light car that is strong enough for batteries is a little
> more tricky, but doable.

Given John's motor choice, I disagree with this -- at least on what 
information we have, until I get a better idea of the motor's 
capabilities....

> I am partial to Saturns.  All pre-2002 Saturns are less than 2400 lbs
> curb weight.  I am personally using a 9" ADC motor with a 2002 Saturn
> SL, at 2400 lbs.

I am uncertain that his motor would fit in a Saturn. Even with the 9" 
motor, we were almost unable to put any batteries above it, which would 
have made it very difficult to achieve a suitable voltage and/or 
capacity. As it is, there is little air gap between the motor and 
batteries. A more definite limitation is the distance to the CV joint in 
a transverse drivetrain. Farver's 10.7" Kostov barely fit, I forget the 
clearance but it wasn't much.


> You will note that among other people with big motors... They mostly
> have lighter cars.  Mark Farver has a 1987 Toyota MR2, at 2400 lbs,
> with an 11" Kostov.  Chris Robison has a heavier 1999 Isuzu Hombre
> pickup truck, at 3300 lbs, with a 13" Warp motor.

I think this is a statement based on unrealistic examples for someone 
who wants an average to above-average vehicle. Farver's intention was a 
very high performance car, built for autocross and donuts in parking 
lots.  :o)  At 1000A, acceleration in his car is extreme, and is 
traction-limited. This is *not* a normal application.  Mine is even more 
abnormal; I'm hoping for 100mph and between 12 and 13 seconds in the 
quarter mile, and I think achieving effective traction will be among my 
most challenging problems. I'm expecting a peak of about 1200 ft-lbs of 
torque, which is in Freightliner territory. Could not find a stock 
transmission that would handle the torque, so I'm going direct drive for 
now. Not a standard application.

11-13" motors are typically used in heavy conversions that need high 
sustained output with lower temperature rise per amp, to overcome 
substantial aero drag. An example is the GMC G-Van from 1989, which used 
an approximately 12" motor, 18 inches long, made by a British company 
called Nelco. It was over 380 lbs, which is close to the weight of my 
Warp 13. Original curb weight with lead-acid was 8600 lbs, 7000 with 
nicad. Controller current was 500A, pack voltage was 216 volts. Even 
with these limits, the van was very powerful, capable of heavy hauling 
and towing.

EVAlbum examples:
http://www.evalbum.com/1102
http://www.evalbum.com/1413

You'd get decent performance in a small bus with a Warp13.


> You could get a BMW 3 series, E90, at around 3300lbs... but your motor
> would not match Chris's Warp 13"... and you would not have a happy
> car.

I think the car wouldn't be happy, but for different reasons.

If normal or somewhat sporty performance is your goal, I would *not* 
recommend a motor of this size. Too heavy, too much motor. A 9" motor is 
more than sufficient even for a light truck. S10s are typically 
converted using a single 9" motor, and these are a lot less aerodynamic 
than a small to midsize sedan or coupe would be. And Farver's MR2 is for 
the moment fitted with Aaron's 9" ADC motor. Power output is not 
substantially reduced; the main difference is faster heating due to 
smaller conductors and brushes, plus higher current required for the 
same torque. Peak power can't be maintained as long.

A 300-400lb motor will need a stout vehicle to carry it. You'll fill up 
space otherwise useable for batteries. And you'll need to limit motor 
current or find a transmission that can take the torque -- for example 
my S10 transmission had a rated input shaft limit of 170 ft-lbs, and I'm 
sure you'll get a lot more than that out of this motor at 1000A.

Basically, if John's motor will do what I'm starting to think it will, 
a) he'll be putting it into a big vehicle, b) he'll be getting *really* 
good performance with it, and/or c) he'll break something. And again, if 
it's going to go in a FWD vehicle, make sure it won't be too big to fit 
beside the CV joint.

   --chris