Keeping an Electric Car Motor Dry

by dale
(AZ)

When I drive in the rain or cross a creek will that tear up my motor? If I buy an A/C motor would I have to buy an inverter?

Hi, Dale -
Don't worry about the motor too much, the motor isn't the problem. It's best not to soak it, because long term it will get rusty...but the real need is to keep the controller or inverter dry.

If you get the inverter wet, you'll toast a very expensive component!

So install it up high, and a lot of people put a flap of something down below the engine bay to keep the water from splashing up.

If you buy an AC motor, yes, you'll need an inverter or VFD to go with it. Some suppliers won't even sell one without the other.

Regards,
Lynne

Tips for Keeping your EV Motor Dry

by Joe
(Ohio)

On the question of keeping the electric car's motor dry:

I built a 'pan' to completely cover the bottom of the engine compartment. This also apparently provides significant reduction in wind resistance. Gas cars can't do this because of all the heat produced by the gas engine. You will also need to be concerned about water coming in through the grille. In general you want baffles or splash shields which make the cooling air change directions before getting to your critical components. Air can easily do this while blown water will hit the first baffle and drain out.

Besides the motor, you also have to be concerned about water getting on the control terminals of your controller. The control terminals on most controllers are looking for a varying fairly high resistance signal from the throttle pot. Unfortunately what you get from water on the control pot terminals is a varying fairly high resistance ...

Curtis DC controllers will shut down if they don't see the throttle in the open position when the run enable signal comes on, so the typical failure mode when water gets on the control terminals is that the motor won't respond to the throttle. The one time this happened to me everything worked properly after things dried out.

Hi, Joe -
Thanks for sharing! That's great information.

Regards,
Lynne