# Can a generator hook directly to a motor without batteries in an EV?



## Ziggythewiz (May 16, 2010)

Possible? Yes (actually you'd hook it to the controller, not directly to the motor). Practical? No. There are several threads on the topic; basically the generator would have to be large enough to provide the peak power needed, which means it will be as large or larger than the ICE you're replacing.

The generator only puts out the amount of power needed by the load. It won't burn up the controller any more than a battery that can provide power doesn't when it's not asked to.


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## TEV (Nov 25, 2011)

Check this up:

http://www.evalbum.com/1066

Possible , Yes.
Recommend, No.

Because every time you transform powers ( mechanical to electric and electric back to mechanical) you don't have an 100% efficiency.


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## alfiez23 (Sep 8, 2012)

OK that makes sense, but I thought the purpose was to replace the ICE? Plus I would think the generator would weigh less than the batteries. I do apologize I am new to this, but If I'm generating 50kW continuously, non-interrupted, and my motor draw 40kW at peak how is this not 100% efficiency. Where do I loss the efficiency? How would this be different from a battery?



Thanks for the reply and the link! I’m going to find the other threads as suggested


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## jeremyjs (Sep 22, 2010)

alfiez23 said:


> OK that makes sense, but I thought the purpose was to replace the ICE? Plus I would think the generator would weigh less than the batteries.
> 
> 
> Thanks for the reply! I’m going to find the other threads as suggested


A generator is an ICE of one sort or another and you need fuel to run it. The goal is to eliminate the need to buy expensive (geopoliticaly, environmentally, and in a real dollar amount) fuel. Getting rid of the ICE and replacing it with something better is just a bonus.


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## alfiez23 (Sep 8, 2012)

jeremyjs said:


> A generator is an ICE of one sort or another and you need fuel to run it. The goal is to eliminate the need to buy expensive (geopoliticaly, environmentally, and in a real dollar amount) fuel. Getting rid of the ICE and replacing it with something better is just a bonus.


Understandable, I may or may not have that covered. So for the pervious questions of mine we will assume that the generator does not use petroleum to run. How the generator creates the energy is irrelevant to me. I just need to know if I can produce the wattage will the motor run correctly. (It sounds like it might.)


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## somanywelps (Jan 25, 2012)

What if you wanted to drive your electric car to another state because you're moving


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## major (Apr 4, 2008)

alfiez23 said:


> ...., but I was wondering if it is possible to hook up a Generator directly to the Motor without batteries?


Sure, that is the basis for locomotive propulsion.



alfiez23 said:


> If so what are the basic components needed for this to work?


Engine, generator and motor.



alfiez23 said:


> (The generator is NOT powered by a source related to the car.)


How can this be


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## WarpedOne (Jun 26, 2009)

> Also if my motor draws 15kW and my generator produces 20kW does my motor burn up? What happens to the extra 5kW?


When your motor draws 0kW, the generator produces 0kW + some heat (if running)
When your motor draws 15kW, the generator produces 15kW + some heat.
When your motor draws 20kW, the generator produces 20kW + some heat.
When your motor wants to draw more than 20kW, the generator produces 20kW and lots of heat and smoke and ...


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## alfiez23 (Sep 8, 2012)

major said:


> How can this be


That's what I'm working on now Replacing/Modifying the engine in your example

Thanks Major!



WarpedOne said:


> When your motor draws 0kW, the generator produces 0kW + some heat (if running)
> When your motor draws 15kW, the generator produces 15kW + some heat.
> When your motor draws 20kW, the generator produces 20kW + some heat.
> When your motor wants to draw more than 20kW, the generator produces 20kW and lots of heat and smoke and ...


Thanks ONE!
Sorry for the amateur hour..


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## WarpedOne (Jun 26, 2009)

OK, now that you've absordbed that one it is time to again turn the tables: motor doesn't really draw anything, current is only a conesquence to voltage that is applied to its terminals. 
Generator produces voltage difference that is able to run the current acording to good old I = U / R. This also means some work is gettng done - how much depends on the current generated power. Higher voltage results in higher current and more power. When generator max power is reached the voltage connot be raised any more. If R contiues to drop (allowing for higher current and more power) generated voltage also drops so generated power doesn't rise. Higher current means more heat losses, rise of temperatures and smoke and finally fire.

It realy is still more complicated than this but let it suffice for now.


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