# advise needed



## greif (Jun 26, 2010)

hi

I would like to convert my john deere gator 4 x 2 to elec. It currectly has a single cylinder 10 hp ICE now and it weights about 900 lbs.

Any idea what I should get for a motor? I would think a forklift motor might be over kill but am here to ask opinions.

I did find this but not sure if it is too small?

http://cgi.ebay.com/D-D-Shunt-Motor...t=LH_DefaultDomain_0&var=&hash=item99ab5ee0e2


thanks
gary


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## madderscience (Jun 28, 2008)

Good Greif-

(sorry could not resist)

The motor you are considering should be about right for a 10hp tractor. To put things in perspective, 15Kw (the peak output of the motor) is about 20HP. (0.75Kw == 1HP) The motor's continuous rating is 2.2Kw or about 3HP. Run the system with the highest voltage you can fit (48V at least, or 4 12V batteries or 8 6V ones or 16 lithium cells) to keep the amps down.

One difference you may need to deal with changing from the gas engine to the electric motor is the ideal RPM range. Chances are the motor will be happier running quite a bit faster than the gas engine. The gas engine is probably designed to run at around 2K rpm most of the time (just guessing on that, check for yourself) whereas the D&D will go up to almost 5000rpm easily. So, you might need to find a way to add a 2:1 reduction compared to what the gas engine did. This may not be a big deal to do if it is belt driven. Just change some pulley sizes.

Other motors you could consider are the "pancake" motors such as the Etek and Perm 132 models. They are also rated for 10-20HP and will handle up to 72V.

Oh and for run time, a back of the envelope calculation assuming you use eight 6V golf cart batteries and cycle them to 1/2 their rated capacity at a rate of 3HP continuous:

48V * 200AH / 2 == 4.8KwH. 
4.8Kwh / 2.2Kw == about 2 hours and 10 minutes.

Good Luck.


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