# Motor/Controller Cooling



## major (Apr 4, 2008)

iss407 said:


> How much heat do a motor and controller generate at highway speeds? Would it be possible to duct that waste heat into the passenger compartment in winter?


Hi iss,

Take the battery volts times the battery amps and you get the power into the controller in watts. Multiply by 0.15 and that will be approximately the waste heat for a good 85% efficient motor and control system. So some quick math tells me that if you are cruising at 15 hp from the motor, you'd have about 2000 watts waste heat. You could duct that up to the cabin, but I doubt you would be comfortable in cold weather. It will take a while for it to warm up. You might get a little warmth by the time your battery is discharged.



> Are there max/min temps for the motor and controller to reach maximum efficiency?


Well, there are maximum temperatures for this equipment. Efficiency for the motor and controller is inversely related to the temperature. The cooler the better, within reason.

Regards,

major


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