What percentage of users will keep this entirely in the enclosure versus mount it in a hole with the fins outside the enclosure?
Inside the enclosure the sink will act just as a heat spreader, a thermal mass, and needs to never get “heat soaked” or otherwise the temp will just start rising again. This can be a great way to “smooth out” pulses of heat though (long or short) depending on the heat load and mass of the sink. If the rider is not pumping in tons of heat into the sink constantly then it can work great. The heat would then be slowly released into the enclosure between the heat pulses.
There’s a bit of radiative and convective cooling inside the enclosure but almost no conduction of heat away from the plate unless the plate is mounted to something else that can help spread out the plate”s heat. If the fins can be exposed to the air flow while riding the efficiency of this sink will skyrocket.
I do want to add that this sink looks gorgeous and seeing this all come together is amazing!
Because of my lack of forum time these days I might have missed it. But are these being shipped? I swear you’re from Ventura and I received a shipping label created the other day. Just sitting there though. Fuck… I get too many things shipped these days…
There was an issue with the mounting plate for those who are using the unity.
The factory put the wrong holes in so he’s taking care of it. so those of us who need it for a Unity are waiting just a bit. @SeanHacker
I believe.the vast majority of users will have them be exposed and if we’re going to go through the process of making an engineered sink rather than just a thermal sponge, it’s worth noting that without access to external air, the sink will not perform all that well to begin with.
By convection I assume you mean the heat removed to the air right? Rather than ir emissions ?
Convection = air cooling, via forced air (fan or while riding) or via thermal air currents rising off the sink in still air.
Conduction = cooling via contact with a solid.
Radiation = cooling by IR emission.
That truly is the million dollar question.
In my opinion there’s no true proper way to do it as a lot depends on the size/weight/dollar budget that is available.
Watertight, of course, means no air flow directly into the box. Enlarging the p-groups adds thermal mass and slows down the temperature increase but costs money and adds size/weight. Spreading out the cells helps to slow down heating (they’re not heating each other as much) but makes the pack larger.
Creating a metal enclosure can help transfer heat out of the enclosure but you need to transfer the heat from the pack to the enclosure. All of the ways to do this add cost and/or weight and/or size. Which to use all depends on what your priorities are for the design.
Sealing the edge of the the heatsink to the enclosure should do the trick. Cut a hole in enclosure so the fins protrude but seal the edge of the sink with silicone. That way the esc conducts to the inside of the sink and the heat moves through the sink to the fins where is is “convected” away.
@mooch, how do you think the oxidation will affect convection? I assume that since convection is fundamentally just conduction.to the air, so the oxide will reduce convection heat transfer just as much as conduction heat transfer.
Yes, @Agressivstreetlamp, the insulating properties of the anodizing can interfere with both convection and conduction but it has a minimal effect on both. IMHO we can ignore the anodizing as it just won’t have much of an effect vs raw metal.
Fin “aspect ratio” (width to height), spacing, air path through the fins, metal texture/surface finish (determines turbulence), etc., will all become hugely important though if the fins are outside the enclosure.
Though it can all have almost no effect if we can’t get the heat away from the MOSFETs and into the sink. That’s the ESC’s job, mostly. We can do a decent job of getting the heat out of the ESC baseplate using a good TIM (thermal interface material) and good, even clamping pressure.
Edit: why the frakk’ does every first reply of mine to a post not link directly to that post?
It will if you click the arrow on the post you’re replying to. It doesn’t show the reply if you do it to the post directly above you though. They will still be notified of it though.
Thanks. I always use the Reply arrow in the lower right corner, I think I do at least, but always wondered why things were so inconsistent in how they got posted. Makes sense now!
Hmm so am I not using the people variable for my analysis? I’m looking at values of thermal conduction (k) for aluminum vs aluminum oxide. Or is aluminum oxide different than anodized aluminum.
Based on the values found in the engineering toolbox, this numbers would be drastically different. 10x reduction.
For the most part this heatsink is removing hear from the esc enclosure rather than from the fets. The esc manufacturer provides metal enclosures that work as thermal sponges, for most higher power ESCs anyway. Not much to do with v4 ESCs
Thanks for all of your expertise. I need to read everything now lol.
I think most users will cut and vent their enclosure for the heatsink, imo it doesn’t make much sense to just add another block of metal to the enclosed space.
That’s the ESC’s job, mostly. We can do a decent job of getting the heat out of the ESC baseplate using a good TIM (thermal interface material) and good, even clamping pressure.
