Re: A 48 volt Freeway EV?

[Grant Wallace <grantwal@bellsouth.net>]

"Wilson, John A" wrote:

> I agree, 96 v is a good compromise voltage for commuter EVs, giving good performance with existing motors while minimizing battery cell count (and thus battery unreliability).  The main problem with 48 volts is that no readily available motor can handle 1000 amps (according to my quick surf though an EV parts catalog).  Installing twin motors, each using 500 amps, could be a possibility. Expensive to do, but the savings in battery expenses and trouble might make this worthwhile to someone.
>
> --Jay Wilson
>
> Seattle
>
> Hello.
>
> Amps=torque
> voltage=speed
>
> If you used a 100amp + controller with 48 volts, you would have kick-butt
> performance for around 1000 RPMs, max. then the performance would drop off
> rapidly. Unless you use gearing that will make around 1000 RPM =65 MPH, you
> will have problems reaching highway speed.
>
> If you are looking for low voltage, but good commuting cars, try 96 volts.
> Even with small 400 amps controllers they can do highway speeds.

Surplus Center has 36v 150amp 6 hp forklift motors for $320. Two of these babies would give 12 hp 1 hour for cruising on level ground, plenty for a very small car (Civic, Fiesta, etc.). They should handle 48v, possibly much higher if done carefully. Being industrial motors they gotta be tuff!


--
Grant Wallace
Chattanooga, TN  USA
grantwal@bellsouth.net

Shadetree Mechanic
Bootstrap Engineer
and "Daddy"