# electric snow machine?



## bblocher (Jul 30, 2008)

dtbaker said:


> I have a friend interested in converting a snow machine to use for setting Nordic track this winter.... I am guessing it will take a fair amount of power to pull the tracker sled and especially if there is new snow. He doesn't have to go very far as the ski loops are fairly short, or very fast.... just unknown power requirements to pull the sled.
> 
> Has anyone done a similar conversion? Any guesses at motor/kWhr that may be needed?


Best thing to do is find what size (HP) engine would be used to preform the same task. Then you can do the math to see what size of motor would be required and calculate the energy to run that for a certain amount of time.


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## madderscience (Jun 28, 2008)

most EV motorbike builds use either an ETEK motor or a Perm 132. both of these are very compact, powerful motors for their size, and they can handle up to 72V. a 72V system would certainly work. The big unknown for most of us here is we have no idea what kind of economy a snow machine (or snowmobile to many of us) gets. At least with a car, a good rule of thumb is you will have comparable range with a lead acid EV conversion to what the car would have done on 1 to 2 gallons of gas.

If you know how many gallons per hour the vehicle burns in the expected usage, then this might work as a guess for battery size to allow one hour of equivalent operation:

(GPH * 33.6 KwH/G) / 4 

The logic here is that one gallon of gas contains 33.6KwH of energy. a typical EV drivetrain is around 4x more efficient than a gas one. So the above calculation would tell you how much usable battery capacity you would need for an hour of operation as an EV. Note that this does not consider confounding factors like any added weight, peukert and maximum DOD issues. If you are using lead acid, you will need to insulate the batteries and keep them heated as they don't perform to well in the cold.

Do snowmobiles use the engine waste heat for anything (like keeping tracks unfrozen, etc?) If so it could be a problem to figure out how to replicate that heating with an EV drivetrain.

Good luck.


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## AmpEater (Mar 10, 2008)

Lots of good info here: 
http://www.megawattmotorworks.com/display.asp?dismode=article&artid=66


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## jorhyne (Aug 20, 2008)

Here is a great snowmobile conversion...http://www.evalbum.com/2545

He's not messin around either, 9 KWH battery and an 80lb motor!


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## JRP3 (Mar 7, 2008)

Snowmobiles are pretty inefficient with a lot of rolling resistance so you'll need a good sized motor, etek won't cut it. 6-7 inch fork lift motor would probably good at 72 volts.


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## dtbaker (Jan 5, 2008)

JRP3 said:


> Snowmobiles are pretty inefficient with a lot of rolling resistance so you'll need a good sized motor, etek won't cut it. 6-7 inch fork lift motor would probably good at 72 volts.


this is what I was thinking.... the stock 'wide track' machines use a 650cc engine, but I don't know what the peak HP is. I am guessing that the 'rolling resistance' will be WAY higher than something with wheels, especially when pulling a sled which is essentially plowing snow. But, it doesn't have to go fast.... 10 mph is plenty, with a 10 mile range (but in cold weather!).


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## JRP3 (Mar 7, 2008)

The cold will definitely cut your range, unless you warm the pack.


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