Improvement #2: cooling the motors - Solid

The car chassis is a big metal heat sink. If the motors are thermally bonded to the chassis, heat should transfer to the chassis and then into the air stream.


Thermally bonding the motor to the chassis is mainly a matter of detail. The goal is the best metal to metal contact with thermal paste filling any air gaps.

The bottom of the motor is fairly rough.

bottom of a motor


It is also not flat.

ruler shows gap  

Luckily, we have power tools.

die grinder  

We progress to finer sandpaper


Smoother is better.

smooth flat motor bottom  

In the car, we do not paint where metal to metal contact is wanted. We polish the inside of the floor with a fine grit, both to clean off contaminants and to get the smoothest surface.

When we fit the motor, we discover the bolts hold the motor slightly above the floor creating a small air gap. We cut an aluminum plate to fill the gap. It is polished and coated with heat sink paste and riveted in place.

note bare metal where the motor will bolt to the chassis  

We apply heat sink paste on the top of the plate and any place the motor will bolt against.

ready for motor  

The motor is installed. Every face including the rear spacers are polished and coated with heat sink compound.


front motor installed


Straps are used to pull the floor up tight to the motor.


strap pulling floor to motor


The whole floor is now a heat sink for the motor.



 Improvement #2 cooling the motors -Liquid
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 Improvement #2 cooling the motors -Air


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