Incredible performance using 3D printed stainless steel heat sinks, handling 175W of heat per sq cm. Yea, liquid cooling is really only good for spreading out point heat sources and can suffer from very low reliability if not done verrrrrry well but this is a nice step up for liquid cooling of high power, high density, cost-is-no-object electronics.
EDIT: I should say that I think water cooling of a board is nuts…too unreliable. But I am intrigued by the technical challenges of doing it and this kind of tech advance is always nice to see.
These things would last until the first crack in the road unfortunately. We crack cast iron hangers here just from repeated stress
And even if they’re super strong somehow and never leak, they take up space that’s invaluable in a esk8, for doing a job some heatsinks with fins would handle just well enough.
They’re interesting, but not extremely useful.
Agreed, there are a couple tiny practical issues. Not impossible to use but this is still the only way I’d ever even consider using water cooling…just as a challenge, a technology demonstrator. Not as any kind of practical thing for someone to do. I think water cooling of a board is nuts so taking on the challenge of doing it well appeals to me.
Having said that, I have zero interest in doing so. As you mentioned, passive cooling can easily match water cooling for the power levels we use and would probably take up less room. Passive cooling would absolutely be more reliable!
They would only really work on a topmount box or a really, really stiff deck+enclosure, then they need to be supported properly and completely fixed, otherwise repeated board vibrations would get the best of them.
Just imagine riding with these over tactile pavement strips with urethane wheels. My feet hurt just thinking about it
@Battery_Mooch i was thinking at one point to buy one large vapor chamber copper heatstrip to soak the vescs heat into the batteries and the deck. One big 150x550 strip, for the hummie deck
Trucks break because they are load bearing. Why would this break if other circuit components don’t break under the operating condition? Also ideally all electronics should be soft mounted.
Actually I would love to use something like this because it allows for radiator part to be outside the enclosure.
Could work well.
You really can’t do much more than spread the heat inside the enclosure and let it slowly “leak” out through the enclosure’s walls or the deck but that is a perfectly legitimate way of cooling off the ESC’s.
I’m wondering if a vapor cooling strip is worth the extra $$$ versus a wider solid copper strip epoxied to the deck or enclosure? Enough surface area and that copper can transfer enough heat to even wood or CF to do the job. As long as it’s still thick enough to (relatively) efficiently move the heat to the other end. Short and wide is better than long and narrow.
Because you have a trampa vesc at ~200g that from inertia suddenly weighs over 10kg pressing or pulling off that thing for split seconds, and that happens maybe thousands of times in a single ride. They would work if they are strong enough, but how thick do they become to be strong enough?
I did a test, from room temperature, used a blowdrier on different components to see how long it takes to make them bump in temperature.
Motors spiked up in about 10 seconds, but vescs in the deck took more than 30 seconds and the temperature was still slowly rising even 5 minutes after. Wood may not have a big thermal capacity but is good enough with enough surface exposed.
Problem is, on hot days, that black griptape on top soaking heat, with copper under giving even more, things get toasty…
Also, any short on the battery to the copper would be pretty damn bad
We don’t shake apart our PCBs (usually), so I don’t believe that 3D printed heatsinks (which don’t experience the stress of trucks) are the first things that will fail due to vibration.
Even then: mount the entire ESC in a simple, urethane shock absorber. IMO all eSkate electronics need better vibration damping than we have now.
What was the MOSFET junction temp at that power level though?
At 250W, using a fairly standard MOSFET junction-to-ambient thermal resistance value of 0.5°C/W that results in a 250W * 0.5°C/W = 125°C temp rise. Using an okay performing standard heat sink setup with a sink-to-ambient thermal resistance of 0.5°C/W that adds another 250W * 0.5C/W = 125°C temp rise.
If we assume a 25°C ambient temp then we have a junction temp of 125°C + 125°C + 25°C = 275°C. The highest junction temp rating I have seen is 175°C for a standard MOSFET.
That MOSFET can be run at levels that high but IMO it won’t last very long.
Even if we use an amazingly efficient heat sink. 0.1°C/W thermal resistance, that results in a 175°C junction temp for the MOSFET. And that is only assuming a perfect distribution of heat across the heat sink (which can’t happen) and a room temp heat sink under the MOSFET (which is impossible). You’ll still be running way above the MOSFET’s rating.
It’s fun to set up stress tests like this though! I’ve done that with some TO-264 FETs I was testing for my electronic loads and it sounded like a 22LR was fired when the MOSFET’s blew.
Yea, liquid cooling is really only good for spreading out point heat sources and can suffer from very low reliability if not done verrrrrry well but this is a nice step up for liquid cooling of high power, high density, cost-is-no-object electronics.
Not impossible to use but this is still the only way I’d ever even consider using water cooling…just as a challenge, a technology demonstrator. Not as any kind of practical thing for someone to do. I think water cooling of a board is nuts so taking on the challenge of doing it well appeals to me.
