# Using a generator to run motor w/o controller



## Tedktis (Jan 20, 2012)

Is it possible to run a gas generator to power an EV motor without a controller? No batteries, just the generator to power the motor. The throttle on the generator could be used as a controller; when the generator rpms go up it would spin the motor faster and lowering the generator rpms would slow the motor. I've tested this theory using two small electric motors. I connected the + and - terminals with wiring and turned one motor (generator) by hand at different speeds so the other motor (propulsion) spun at the same speed I was turning the generator motor. The reason I want to do this? I can not afford batteries and controller at this time, as well as needing unlimited range (gas). This would be similiar to the Chevy Volt running it's gas generator to power the electric motor when the battery pack is depleted.


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## major (Apr 4, 2008)

Tedktis said:


> Is it possible to run a gas generator to power an EV motor without a controller? No batteries, just the generator to power the motor. The throttle on the generator could be used as a controller; when the generator rpms go up it would spin the motor faster and lowering the generator rpms would slow the motor.


Possible? Yes. Practical? No. You'd be much better off just driving the wheels directly with the ICE and forgetabout the electric generator and motor with their inefficiencies, weight, cost, etc.


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## Tedktis (Jan 20, 2012)

major said:


> Possible? Yes. Practical? No. You'd be much better off just driving the wheels directly with the ICE and forgetabout the electric generator and motor with their inefficiencies, weight, cost, etc.


Agreed, but by doing this it would 1.) make it possible for me to begin to build my project, 2.) be able to use the vehicle and 3.) have an extended range for long trips once I do install batteries, controller etc. Also, the Chevy Volt gets over 30 mpg when running on gas after its battery is depleted. So with a lighter vehicle I would probably get better gas mileage than I am with my current vehicle. Or am I incorrect in my theory? Does anyone know of a build such as this?


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## Jan (Oct 5, 2009)

Tedktis said:


> Does anyone know of a build such as this?


It's a common setup in Ice breaker ships, or how you call them in English. It makes it possible to position the engine anywhere in the ship. And in this particular case that's in the front. They need a lot of weight in the front of the ship.

And I'm not so sure every Diesel locomotive has a battery pack. They are mainly hybrid because of the need of enormous starting torque. That can be done just as well without batteries. It would make them more efficient, not necessarily stronger.


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## frodus (Apr 12, 2008)

get one of these:
http://www.lightobject.com/Programm...th-dual-control-Good-for-HHO-System-P408.aspx

if you just want to turn it off.


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## Tedktis (Jan 20, 2012)

frodus said:


> get one of these:
> http://www.lightobject.com/Programm...th-dual-control-Good-for-HHO-System-P408.aspx
> 
> if you just want to turn it off.


Great Idea!


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## Tedktis (Jan 20, 2012)

gottdi said:


> How often do you really need the extended range? In other words how often do you go more than like 50 miles in one day? If you truly go more than that then you should just get yourself a nice TDI and run bio and then work on your project as a side line. In truth it might just cost you more to build your gas engine generator to electric motor set up than it would to just build a straight electric with lithium batteries and controller and motor. As for doing it without a controller, I don't think you will be able to do it properly. Your gas engine will be running the generator so always producing power. Power may vary and you need good control of that power. A controller will most likely need to be used anyway.
> 
> You still need to maintain the engine and all those components too.
> 
> ...


I don't need the extended range for long trips to often, but the reason I would need it is for performance. I would like to be able to 40 miles a day plus drag race it down a private road. The generator idling problem is solved. As far as mainting the ICE motor I am trying to find something very efficient/low maintenance or something with a lot of performance. The trike is something I was considering!


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## Tedktis (Jan 20, 2012)

I also wanted the generator for emergencies.


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## Qer (May 7, 2008)

Tedktis said:


> Is it possible to run a gas generator to power an EV motor without a controller?


No.

You need some kind of controller. Period.

You can build an EV without batteries and only a generator, yes, but it would be pointless bordering to idiotic to not have any batteries at all. A small, high power, pack for acceleration and to averaging the load on the generator (which is what a Prius has for example) is a huge step and why those hybrids get a better MPG than ordinary cars, but without any battery pack at all you'll most likely end up burning more gas, not less.


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## Jan (Oct 5, 2009)

Qer said:


> No.
> 
> You need some kind of controller. Period.


I do not agree fully. If the throttle is connected to the 'generator' the output power of this generator is more or less 'controlled'. 

And I find the Ampera or Volt a better example than the Prius. The Prius is a lot more complecated, it only 'generates' when cruising, and only if there is a surplus of power and the battery pack needs a little juce. And during braking ofcours. 

And there are in special cases other reasons than efficiency. Like in my earlier examples of Ice breakers and Diesel locomotives. The first Diesel electric locomotives didn't have a battery pack, and I doubt they had a controller too.

I can imagen in an odd 4x4 application the absence of drive shafts could be a very strong argument. 

Just to disagree.


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## DIYguy (Sep 18, 2008)

Tedktis said:


> I don't need the extended range for long trips to often, but the reason I would need it is for performance. I would like to be able to 40 miles a day plus drag race it down a private road. The generator idling problem is solved. As far as mainting the ICE motor I am trying to find something very efficient/low maintenance or something with a lot of performance. The trike is something I was considering!


How would this set up be good for performance? Would you have a generator that puts out say... 1000 amps? Most gen-set applications tend to be the other way. . . they put out smallish current levels to augment/extend range. I don't think you could carry a gen-set that would give you "performance". Then again, I've been wrong before.

On another note, I'm one of the guys who has actually built an ev with a gen-set to extend range. Technically, it works. My opinion of it is... really not very practical at all. The main reason I say this is because it's very loud. I bought a top quality generator, Honda engine. It's still bloody deafening. Going through town, ppl look at you like you are a whacko....lol I'm not saying that a quiet system can't be done however, the standard idea. . buy a generator and add it to the mix is just not something you will end up doing for any length of time IMHO.


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## Tedktis (Jan 20, 2012)

Qer said:


> A small, high power, pack for acceleration and to averaging the load on the generator (which is what a Prius has for example) is a huge step and why those hybrids get a better MPG than ordinary cars, but without any battery pack at all you'll most likely end up burning more gas, not less.


Okay, now I understand. Although still possible, not at all a good idea. Thanks for the info.


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## major (Apr 4, 2008)

Qer said:


> Tedktis said:
> 
> 
> > Is it possible to run a gas generator to power an EV motor without a controller?
> ...


Hi Qer,

I thought about the easy "no" answer for my post #2 reply, but told him it was possible, just not practical, that is for EVcars.

I actually made such a generator powered electric drive vehicle. And it worked very well. But it wasn't an EVcar, it was an IUV (Industrial Utility Vehicle). Its primary purpose was the transport of a gas fueled welding generator and secondary purpose was the transport of the operator.

We used a golf cart size 6.6" series motor to power the front axle. First off we used a Curtis motor controller connected to the welder DC output. But under acceleration the voltage would drop too low and the Curtis would UV fault. So we threw the Curtis out and connected the motor to the welder output. Used the potbox to control the generator field and microswitch/latching circuit for 2 engine speeds. It was completely controllable and the generator took care of current limiting. No motor controller, no batteries 

Now this was a special case. And it was a 20 hp engine driving a 10 KVA generator for a 3 hp electric motor. So if it required similar sizing for an EV car, you'd need a 500 hp engine and 250 KVA generator.......Not practical 

Regards,

major


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## lazzer408 (May 18, 2008)

I'd love to hear more on this thread. There's one advantage. The ICE can run at a steady RPM where both the intake and exhaust can be tuned for more then 100% volumetric efficiency. Question is, are the gains from "rpm tuning" greater then just the ICE alone in a typical wide-range RPM application?


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