Can I Power My AC Electric Car With an AC Generator?

by Aaron
(Slidell, La.)

I want to build an electric car but I don't want to have to carry around all those batteries. It's not just because of weight or anything, just that batteries are toxic and disposing of them is hazardous to the environment. I don't mind using a few to buffer the current, but i feel 20 batteries in a car will eventually cause more pollution than just burning gas.

Hi, Aaron!
You raise a good point.
What happens to those lead acid batteries we use to run our EVs after we take them back for recycling? As of today, the answer is "nothing good". Like it or not, if we care about people or the environment, we've got to deal with this unpleasant fact.

So you got the idea to put an AC generator in your car, and wondered if you could dispense with the batteries.

The answer is yes and no. I talked with Alain St. Yves last week about his "Green Vehicles", which are electric cars with full battery packs that he recharges on the fly with a 5kw AC generator.
When I asked him if he could just skip the batteries and run on the generator, he said: "You need batteries for the power required during acceleration; it can be 30 to 50 Kw on acceleration. On the highway, the car requires somewhere between 15 and 25 kw. A generator equal to the average power required (15 kw) will maintain the car for very long distance but will not be able to accelerate the car if there is no battery for that power requirement. My generator is a 5 kw, for 5 kw you need 11 hp engine. So for a 15 kw, you would need some 30 hp engine which is quite big for a homemade generator."

Hope this helps, Aaron, and good luck on your project.


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Electric Power Generator With AC Motor

by Mary
(New York)

Electric Power Generator

Electric Power Generator

You mentioned that you could run a small electric power generator to run an AC motor and the motors mentioned were the Solectria AC55 motor and the Solectria AC24 motor. I'm a bit confused about how much power would be needed from a generator to power these AC motors?
Also, how would you change the power for what is needed for the motor and where could I find that?

Hi, Mary!
Tossing your question over to Dan Bentler, the motor man...

He says:
You would need an alternator (3 phase) to drive these directly. It would have to have the same KW voltage current as the motor and probably more to allow for starting current of motor - I would guess by added 10 and maybe 20%. The load driven by motor has a torque demand and this is what controls the whole "chain" i.e. load motor and alternator. load torque only 50% of full load then motor delivers only 50% and demands only 50% from alternator which only demands 50% throttle on prime mover.
- Dan

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