why not oil cooled controllers

[Harold in CR]

If computers can be immersed in oil for cooling, why not motor controllers ?

Seems like it might alleviate burning up controllers ?

Tiny pump to circulate the oil, or natural convection, maybe ?

Small motorcycle radiator for cooling the oil?

 

[Drunkskunk]

There are some higher end controllers that are oil filled for cooling. seems to work fine for them. The problem with an ebike controller is trouble in sealing all the wires that would have to exit the case.

If it was something I needed, I think I would liquid cool just the FET's heat sink, with the same system used to cool a computer's CPU. I've got a Corsair water cooling setup on my i7 4770, which can keep the temp down even when the CPU is pumping out 85 watts or waste heat. that's much more than most controllers are going to dump as waste heat.

 

[Harold in CR]

Actually, I was thinking more along the lines of dunking the whole thing in a sealed box. Then, the wires could exit out the top or high on the sides, using the proper seals for cables. Then, circulate the oil from the box to a radiator and back.

Non conductive fluid should well, no ? I have these hills to run and just blew a 15 fet controller from heat issues I believe.

 

[Hillhater]

Its been done on here before.
Try a search, a few threads should come up.

 

[Harold in CR]

Ok. Did a quick search and found nothing before I started this thread. Will do a better search. Thanks

 

[Hillhater]

Harold.. This thread from 2011 by "karma" was on of the first to show the use of oil filled controller use....but i fear many of the photos etc are missing now
https://endless-sphere.com/forums/viewtopic.php?f=6&t=25286&start=50
But there are many other threads on the topic...use the google search option.

 

[Harold in CR]

Thank you. Lots of lightning here today, so, very limited time with computer. I will do some searching.

 

[Harold in CR]

Did a better search and found the threads. Thanks Hillhater.

 

[Baron]

Actually, I was thinking more along the lines of dunking the whole thing in a sealed box. Then, the wires could exit out the top or high on the sides, using the proper seals for cables. Then, circulate the oil from the box to a radiator and back.

Non conductive fluid should well, no ? I have these hills to run and just blew a 15 fet controller from heat issues I believe.

sealing it in a box would remove the passive airflow from riding though. I'm interested in this as well, couldn't it be as simple as filling the controller with mineral oil, and making sure the side that the wires are coming out are facing upwards?

can you share the threads you found?

 

[Harold in CR]

I was thinking that the more circulation, up to a point, would carry away enough heat, so that the controller would not get overall as hot as any air flow situation would allow.

I was thinking about not even having the controller case involved in the sealed box, just allow all the heat to freely escape, by mounting the innards of the controller to the sealed box/tank. Why spread the heat from the parts that normally get hot throughout the controller case ?

One part of the links I found, stated that the controller was sealed and as the load was applied, the case of the controller got very hot, showing the oil was doing it's job carrying the heat, BUT, there was no place for the oil to dump the heat except for the air flowing across the case ? That's like filling a bottle with water, and once it's full, that's it's limit ??

When computers are immersed in oil, the boards are out of the case and the cpu fan is running, which mixes the heated oil with the lesser heated oil. That's what I think might be a better solution to taking away the heat.

https://endless-sphere.com/forums/viewtopic.php?f=2&t=50826

https://endless-sphere.com/forums/viewtopic.php?f=3&t=40549&hilit=oil+cooled+controller
This second link had lots of discussion which is what I was after. Chalo and Jeremy made excellent points where the bottleneck of the heat removal was located.

 

[markz]

The CPU water cooling idea would be the best. I've been looking around for cheaper alternatives, as most CPU water cooling units are expensive, but you could build you own custom block, then the only major expense would be the pump, perhaps build your own resevoir too while you are at it, some automotive tube and you are set.

 

[Harold in CR]

When I get a chance, I will do some experimenting. Back when the Model "T" was built, there was no water pump for engine cooling. Principal was, heat rises, so, plumb the top engine water outlet to the top of a radiator, and, as the water gets hot it slightly forces the cooler water in the radiator to flow to the bottom and back into the engine low entry point. Simple convection cooling.

This is what I envision. Moto radiators should be small enough to cool the oil and not be bulky. I have never messed with this stuff, but, will do some checking when I get to Fl soon. I want to do a moto conversion and try this system. Here we have small motos. In the states there are dual top rail frames that should allow a 96V 45Ah Volt battery conversion to be done. Do some aero mods and possibly get 100 whr/mile or better and could be 50 mile range with regen.