return to homepage

DIY Hybrid Electric Car: Using an AC Generator Head with a Small Electric Motor

by Jason G.
(Pax, WV)

Well, this is more a suggestion, rather than a question, on how to build your own hybrid electric car.

The average 4cyl car motor weighs about 700 lbs, give or take a few pounds. Why not use a AC generator head and use a smaller electric motor to push that generator head to power your ev drive motor?

See, the mid size and larger trucks require you to at least have 200 fpt to efficiently push the larger vehicle down the road at average load. Now I also live in the mountains, so I've thought about this conversion for months. and I've built a house generator with the same technology provided. used a 20kwt generator head and a 2hp 3 phase ac motor that only requires 2200 watts to run @ max load. I used basic geometry to calculate the gearing needed(or pully system)so I can get the generator to run @ 3/4 power while the drive motor to only run as 540rpms. you'll never reach max load on the supply motor, but it is always safe to buy something of that magnitude so in case you need it, it's there. The system generates power for the house, and some power back feed into the drive motor to turn the generator head...essentially it powers itself in the long run. it's the same setup only you're going to use a 30kw generator head, and a 3hp industrial AC 3 phase motor to power the generator head.

The drive motor that you'll use shouldn't be no more than the max output of the generator head. A good calculation I use makes the generator head work efficiently with your current setup, basically eliminating the batteries, except two (which turn on the small 3 phase motor to start your EV up), the calculation i used for my house usit to power my garage stuff (including 240amp welder) was.. take your max load of the motor (wattage to run @ max load), or power source you plan on powering...times max load (wattage)by 3, then divide the total number by two. this will give you what you need to run the motor @ 3/4 power range, and won't overload your drive motor. See you're gas guzzler motor (like a v8) weighs about 950 pounds dry. and the ev motor + the generator head & supply motor only weighs about 80 pounds less, you'll eliminate alot of weight by taking alot of the weight from the batteries off.

You'll be able to drive further, since your system is producing the power on demand, rather than relying on batteries to get you places. Another thing is that the hills or mountains, you'll use much more power from your batteries to push you up those hills, dampening your mileage greatly. And with this system, you'll have that power to tap whenever you need it. rather than watching your power gauge drop like you're driving a dragster on the back roads going from 180 to stop, and again...until you run out of power all together.

I've also built a few EV's including golf carts, and off road dune buggies. This idea isn't mine though, it was patented nearly 23 years ago, and I happened to stumble on it while searching for alternatives to gas powered trucks.

So, I'm not going to claim this idea, though from the original setup I changed the ratio of the pulleys, rather than using a motor to motor straight shaft. Allowing me to run supply motor at 1/4 power, and generator head @ 3/4 power. using pulleys already provided for us (thank you automotive industry) LOL

If you got anymore questions, feel free to ask..btw..only thing you're doing is replacing the batteries with a generator you keep the same controllers and electrical system used on the prior conversion from gas to electric. An rather than having limited mileage, the power is on demand, enabling you to go much further.

And I will agree on using an AC motor over a DC motor, with this setup...there really isn't any need for inverters, since the generator head supplies AC power already.

Hi, Jason!

Sounds like something that needs to be built and tested. If it works, it works! Keep us posted, okay?


Comments for DIY Hybrid Electric Car: Using an AC Generator Head with a Small Electric Motor

Average Rating starstarstarstarstar

Click here to add your own comments

Why is this so hard to believe?
by: Anonymous

I don't understand people on the internet any longer. It used to be that everyone on the internet believed that anything was possible. Now someone comes up with a slightly unique idea and everyone jumps on him and says it won't work. Well, it does work because I did it. I used a 7.5hp motor though, run by a 6500 watt genny in a Honda Civic and it worked fine. It wasn't a speed demon, but it would get me around. The neat thing about mine is that I used a free alternative fuel to run the genny (no, not oil - think about something even easier to find . . . and research alternative fuel cars in WWII) I had the same problems you did my friend. Trying to get assistance for my idea was next to impossible because everyone said it wouldn't work. Luckily I was an engineering student and was able to get help from professors, other students, etc. There's nothing strange about this idea. The reason it works is because electric motors are 90% efficient on average, while gas motors are only about 45% efficient.
This is the world we live in now I guess - people said the same thing when I decided to build a home in the woods of MO without electricity or power tools, but I did that too in 6 months, had hot water & a kitchen stove, both running off of another free fuel gas/vapor. People need to stop thinking that the only way to do something is how everyone else does it. Think for yourselves and please stop being sheep.

2 HP 3 Phase motor
by: PFR

how do you run your 3 phase motor out of 2 batteries?

Do you have the patent number
by: JJ

Hi, I'm JJ and i'm doing my science project on electric cars and I would like to include information on the generator you described. You said you stumbled across a patent for this generator. Can you provided me the patent number so i can include it in my research part of my project.

Hi, JJ -

Hopefully Jason will see this message and respond with the patent number. Good luck with your project!


by: Jim

That one's got me beat..... Forgive me if I read that post wrongly.... Large genny powered by small motor drives EV.

Please can you provide a link to the original idea? If that works I'd advise everyone to sell their oil company shares immediately!

It's the other way around, Jim - the generator is powering the motor. The motor runs the car. The generator feeds power to the motor. I would say "charges the batteries", but in this case he's trying to replace the batteries with a generator.

The idea is that the electric motor is a lot more efficient than a gas engine for the actual "moving the car" power needs; so people get the idea that it would be a good idea to replace the gas-guzzler's engine with a smaller, lighter, more efficient electric motor.

So far so good.

Then, they realize the batteries are heavy, awkward things, and limit the range of the electric car to 50 miles or so. What to do about that? How about a generator to feed electrons back into the batteries?


Why do we need batteries at all? They're heavy and taking up valuable space.

Well, because a generator's nature is to be set to one speed, either on or off. But a car's nature is to need a variable amount of power. When going up hills, accelerating, this takes a lot of power; when cruising along at 60 mph, not so much.

Jason proposes to solve this problem without batteries by getting his generator to give "on demand" power, while getting maximum efficiency with the electric motor actually doing the work of moving the car.

...I think.

- Lynne

Too good to be true
by: Anonymous

I would really really love to think that this would be feasible, but it must be too good to be true. Isn't that called a constant momentum machine. Someone please verify that this could possibly work. Urban legend would have this idea executed.

Contacting david on house generator
by: Tommy

I would like to see pictures of your generator that is running your house, I would like to build one but I don,t know what will and won,t work, I would appreciate your advice if at all possible.

Click here to add your own comments

Return to Motor Q&A.

New Book!

Let's Talk About Electric Cars book

From Electric Cars are for Girls

Conversion Help

EV Conversion Videos

EV Conversion Videos

Electric car Conversion books

EV Conversion Books

CanEV Conversion Kit

EV Conversion Kits

Conversion Info

Electric Car Conversion

Conversion Central

electric car conversion

Build Your Own

Electric Car Motor

Electric Car Motors

Electric Car Batteries

Electric Car Batteries

[?] Subscribe To This Site

follow us in feedly
Add to My Yahoo!

Charge On! Newsletter

Once a month (or less), I'll send out a newsletter called Charge ON! with the latest interesting electric car stuff.

To get on the list, fill in your name and email address below, and I'll send you a note to make sure it wasn't the DOG that subscribed you by accident; )




Don't worry -- your e-mail address is totally secure.
I promise to use it only to send you Charge On!.
Enjoy This Site?
Then why not use the button below, to add us to your favorite bookmarking service?

| Electric Cars are for Girls Homepage | Privacy |Contact |About Me

Copyright 2006-2014 All Rights Reserved.