# adding 12hp gas motor to electric car



## nulluser (Mar 4, 2012)

I have been thinking about adding one of the Chinese yanmar diesel clones to my saturn project.

I think I would rewind a car alternator to give around 165 volts to float charge a 144 volt pack. The alternator would be directly coupled to the engine. (No speed increaser or belts to slip or break)

There would be some logic that checks the battery voltage, and if it drops below X for some amount of time, the diesel starts up from the aux battery and starts either charging or assisting the batteries. 

For the cuoff, I would check the alternator current, and cut the generator out if it drops below Y for some amount of time.

There are some things to think about, including if you want to allow unattended start or operation of the generator. 

It would be nice to be able to control the stator voltage directly to setup current limits. Otherwise you might bring the RPM too low during acceleration or even stall it.

The dream of course is a miniature bio-diesel processing station on board, and the ability to run on waste cooling oil


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## dubelt (Sep 27, 2011)

why 12HP not smaller?
what is your average speed?

I thing the best solution would be generator rated with power equal to average power consumption / average speed power.


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## dougingraham (Jul 26, 2011)

otp57 said:


> To extend the range od electric car( if I run out of juice) I need ideas to install a 12hp gas motor to VW bug.


12HP would give you about 6500 watts to charge the battery accounting for the generator and charger inefficiencies. At an estimated 250wh per mile this would extend your range by about 26 miles per hour of operation. You really need about 40HP if you want to arrive at your destination with a full pack. More if you have to climb long grades. 12HP just isn't enough.

Given that current battery technology gives us cars with a very reasonable range of 100 miles I would be delighted to pull a well engineered trailer with perhaps a 60HP motor generator set. Something that could be rented for those rare long trips. Having a generator set on board seems like a good idea but for 99% of driving it is just an extra very complicated system you have to haul around. By well engineered, it would have to be aerodynamic and at least as green as most modern cars. Lots of engineering to get to that point.

Best Wishes!


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## madmike8 (Jun 16, 2011)

I'm building a light weight 1000lb T-Bucket for short range driving. I drive 12 miles round trip a day and I'm building for a 30 mile range. The only time I would need more range than this is if I wanted to take it to an EV show or something. It would be nice to have a pull behind trailer with like a stock aircooled VW 4 cyl engine hooked to some kind of generator. and some room for storage built above that. Has anyone seen a build like that?


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## mizlplix (May 1, 2011)

No, but it sounds do able.

Miz


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## meanderingthemaze (Jan 25, 2010)

madmike8 said:


> I'm building a light weight 1000lb T-Bucket for short range driving. I drive 12 miles round trip a day and I'm building for a 30 mile range. The only time I would need more range than this is if I wanted to take it to an EV show or something. It would be nice to have a pull behind trailer with like a stock aircooled VW 4 cyl engine hooked to some kind of generator. and some room for storage built above that. Has anyone seen a build like that?


Like this?
http://www.mrsharkey.com/pusher.htm

http://www.jstraubel.com/EVpusher/EVpusher.htm


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## madmike8 (Jun 16, 2011)

Nope... Not like that... I'm not sure of a pusher when my all up weight will be 1000lbs. I want the engine to run a generator which will run the motor in the car.


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## meanderingthemaze (Jan 25, 2010)

Ok, so disconnect the CV shafts and add another belt/pulley to run the generator off the crank. Now you have your freewheeling-pull-behind-VW-engine-powered trailer.


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## madmike8 (Jun 16, 2011)

meanderingthemaze said:


> Ok, so disconnect the CV shafts and add another belt/pulley to run the generator off the crank. Now you have your freewheeling-pull-behind-VW-engine-powered trailer.


Laugh... Ok that might work...


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## meanderingthemaze (Jan 25, 2010)

But, keep the brakes!


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