Quick and easy cooling for a motor controller on my Electrathon EV

[blackbird42]

I need ways to cool a 99mmx40mmx33mm Grin Technologies V6 Phaserunner 36-72v motor controller during 2 separate 1 hour long races. As of right now, it has 2 heat sinks (one with thermal paste and one without) and exposed to ambient air, but it is not enough. The car is still bogging down and loosing performance due to heat. We have 1 class period before our race on May 2nd, the period is 3 ish hours long, this one component is stopping our full potential of 35mph

Below I'll put the drawings of the controller and heat sink
Phaserunner - https://ebikes.ca/amfile/file/download/file/115/
Heat Sink x2 - https://ebikes.ca/amfile/file/download/file/340/

So far, we have the controller sandwiched in-between 2 heat sinks (the one on top has thermal paste), and our idea was to zip tie a wrapped freezer gel pack to the heat sinks to keep them cool and help push the full potential of our battery through

Battery specs - 24 cell, 20 amp hour, 72-80 volts

 

[lnanek]

You could do that math, but I can't imagine a gel pack would do anything meaningful. Just body heat is enough to melt those in a matter of minutes. It wouldn't mean much re machine produced heat.

Why not grab a little fan off an old PC and rig it up to a couple 18650's and slap it on there for active cooling? Or even feed it off the traction pack via a buck converter if you have that setup.

It's not a rare solution:

https://insideevs.com/news/793256/verge-ts-pro-gen2-solid-state-cooling-pack-configuration/

 

[blackbird42]

You could do that math, but I can't imagine a gel pack would do anything meaningful. Just body heat is enough to melt those in a matter of minutes. It wouldn't mean much re machine produced heat.

Why not grab a little fan off an old PC and rig it up to a couple 18650's and slap it on there for active cooling? Or even feed it off the traction pack via a buck converter if you have that setup.

It's not a rare solution:
View attachment 387473

https://insideevs.com/news/793256/verge-ts-pro-gen2-solid-state-cooling-pack-configuration/

didn't even think of that, i will try that

 

[neptronix]

I was thinking peltier cooler, but that might consume too much energy; a fan is probably good enough

 

[Apartunis]

Water mist cooling on the heatsink.

 

[PaPaSteve]

The original Electrathon rules only allowed power from the traction battery with a small exception for speedometer or radios etc.
Traction batteries were sealed lead acid of 73 pounds total.
Back in the day . . . a common controller cooling scheme was a NACA duct design directed to the over-heating area.
Assuming your car is an enclosed streamlined design.
I had the opportunity to competed in the original American Electrathon at Cerritos College.

An edit to mention the current rules have an advanced battery class allowing several other battery chemistries.

 

[AdR]

Have you tried a heat sink with a thicker mounting plate/base to act as a heat dam plus more fins to increase cooling surface area. The grin one are cute but not effective for high power applications.

 

[OlderGiantFan]

Why not grab a little fan off an old PC and rig it up to a couple 18650's and slap it on there for active cooling?

A race, at speed... Directed airflow over the heat sinks, that's where I'd start. Channeling as much airflow across them, mount them out front even? For years old lawnmowers would overheat and conk out, until one day they thought of mounting a fan on the end of the crank above the head fins to blow a gale down across them. Now all small engines have that, 2 stroke and 4. But none of those machines are moving through the air at speed. Motorcycle radiators have high speed fans but they never kick in if the bike is moving along at pace. Most sit around 80-deg C just from directed airflow alone.

 

[ProEV]

Battery specs - 24 cell, 20 amp hour, 72-80 volts

So I think you might be trying to fix a symptom rather than the cause. Electrathon Advance Battery class is limited by weight and by pack capacity as specified by the manufacture. The Pack capacity limit is 1,000 Whrs. If your voltage is 80 volts, running for an hour, you should average 12.5 amps which should be fine since "the continuous current capability without additional heatsinking is typically 45-50A."

The biggest problem is that your pack does not fit under the rules. From the 72-80 volts, I am guessing you are running LiFePO₄ (LFP) with a nominal voltage of 3.2–3.3. To calculate pack capacity we multiply nominal voltage per cell 3.3 times 24 times 20 amp hour rating which gives us V24 x 3.3 = 1,584 Whrs.

Ignoring the rules problem, this pack capacity still gives 1,584 / 79.2 = 20 amps of current, well below the Phaserunner's rating. Why is it overheating?

You are within the voltage limits "Wide operating voltage range from 20V to 90V (21S Li-Ion, 24s LiFe)" and the power limits "It is ideally suited for running brushless motors for electric vehicles in the 500-2000 Watt power range." My guess is that the controller is not programmed correctly for the motor. Are you confident in the set up?

Cliff

ProEV.com