Portable Generator in Your Electric Car:
Build Your Own Hybrid

Can you put a portable generator in your electric car to extend the range? Yes! In this interview, Alain St. Yves - one of the pioneers of the do-it-yourself plug-in hybrid - says if he can do it, so can Detroit.

When Alain St. Yves built his original "Vehicule Vert" in 1998, it was a standard DC Chevy S-10 electric conversion, 144 volts, offboard charger.

What's really different about Mr. St. Yves' electric truck is that he installed a 5 kw portable generator in the back, which he built himself out of a 3-phase AC motor and a small car engine - with the help of some of the guys on the EV Discussion List - and increased his truck's range from 40 miles to 80 miles on a charge.

Never worry about finding a place to plug in

Lynne: Alain, your Cavalier's EV Photo Album page says it has "80 mile range with a 5kw generator, or similar to a conventional ICE with a 15kw generator". Do you have two portable generators for the car, depending on how far you'd like to travel?

Alain: No, the Cavalier has a 5kw motor installed permanently. I was thinking of the special 3000 km challenge going from Valleyfield to Baie James, North of Quebec province that I did in 2003 driving the S-10 conversion, the original "Vehicule Vert". It had a 5kw portable generator, and then a 10kw trailer generator behind it.

There have been two "Vehicules Vert", then?

Yes, the Chevy S-10 conversion I built in 1998 and then later a Chevy Cavalier conversion. Both have 5 kw generators installed to extend the range of the battery packs.

If you want to engage the generator, how do you do it? Can you start the generator while the car's running?

Yes. There is a remote key to start the portable generator near the seat of the driver, it's the red unit near the passenger seat in the picture.

On the floor, passengers side. I see it.

When it's running, on the left side of the driver seat, there is an idle or full throttle lever. You don't need to play with that, you use it full while the generator is required and put it idle before stopping the engine. Sometimes on a longer trip I will stop for coffee somewhere and let the generator charge in the parking lot for 20 or 30 minutes. The generator gives 30 amps that way. The nice thing about having a generator in the car is that you never worry about whether or not you can find a place to plug in.

While I'm on the highway, I always use the generator. When I'm in town, as when I drive across Montreal for instance, I turn it off to cut out the noise and pollution. If everybody did that, there would be no more car exhaust pollution in the city!

With a portable generator for power, do I still need batteries?

A lot of people ask, if I've got a generator, why do I need batteries? I tell them that driving demands a variable load, because of acceleration and getting up hills, and a generator supplies a constant amount of electricity. Am I right?

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.

So you'd need a huge generator for acceleration, much larger than for cruising on the highway.

A generator equal to the average power required (15 kw) will maintain the car for very long distances but will not be able to accelerate the car if there is no battery for that power requirement.

How many HP does the portable generator need?

Your generator is only 5 kw, so your battery is doing most of the work supplying the energy for the motor. The generator just recharges the battery. How many HP is your engine to generate 5 kw?

I've got 11 HP to generate 5 kw. So for a 15 kw, you would need some 30 hp engine which is quite big for a home-built portable generator.

So do you take the generator out when you don't need it?

The S10 is actually used in electric mode locally. The generator was moved some time ago from the S10 to the Cavalier. As far as moving the generator in and out as you need it, it's really only a question of the way you install it in the vehicle. In the S10, it's was not a big job to move it in and out. In the Cavalier, it is installed under the rear of the car, the best thing is to keep it there.

And how do you keep the exhaust from the generator from coming into the passenger cabin?

There is a blower that forces the air from the inside of the car to go in the generator box. It has the effect of both cooling the motor and bringing fresh air for the engine, at the same time pushing the polluted air out, because the bottom of the box is open.

Merci, Alain!

Electric Motor Choices

For More Information

For more information and photos of Alain's fabulous conversions with portable generators, follow the link to his website.

Hey, did you see that first picture where M. St. Yves is standing in the snow next to his electric S-10? I've collected some tips on how to keep your EV running smoothly when it's cold.