How-to: Heatsink your VESC!

ESK8 Electronics
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Credit to @Chaka and Enertion for offering their VESC and VESC-X/FOCBOX in some sexy aluminum enclosures/heatsink sandwiches! (just llaid hands on @smurf’s direct-FET Ollin VESC - gorgeous!!!)

But i don’t have either. And I want a heatsink. As much for cooling as secure flat mounting!

So i’m going to start off focusing on the base plate (easier w/ no “cutouts” needed for UART/Sensor/etc. plugs).

A quick trip to the local hardware store had some 1/8" aluminum that is perfect width:

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(4 feet should give me plenty for a few!)

Working with basic tools (no CNC yet), i took some measurements of hole spacing (not perfect i’m sure), and found the intersections and punched them:

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I measure it out, cut with dremel cutoff wheel, and sanded the ends to clean them up a bit. Again - not perfect (and i’m totally OK with this - function over form).

Once i confirmed alignment with the VESC holes, I used the first as a template and clamped them together to drill the rest out on the drillpress w/ 1/8 bit (closest - smidge bigger than VESC holes in mm).

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Spacers to raise the PCB above and clear the aluminum… I got a bunch of fiddly little copper squares in different thicknesses specifically for this… and then i tested one of the pieces of aluminum and the 1/8" thickness worked GREAT as the standoff/spacer! So i cut 2 before my dremel needed re-charge and it was starting to get late… I cut them 12mm wide. So even after sanding edges smooth - still a bit generous. Plus a bit of overhang of the FET and leeway for less-than-perfect alignment/placement.

Some Arctic Silver adhesive, a stir stick and VOILA!

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(rough sanding to get burrs - will have a thermal pad or arctic silver thermal paste to fill in the scratches and imperfections for good heat transfer). This is not the 90’s AMD Athlon i lapped for OC’ing…

It’s getting on “stupid late” and need to crash, but a quick test fit to show the plan:

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I will cut back (but not fully remove) the heatshrink - so the FETS are flat and in contact w/ the aluminum spacer/riser block, and use some plastic m3 to secure to VESC. I’ll try to show some pics tomorrow when i start those next steps.

So that’s the plan folks - a quick and easy DIY heatsink for a VESC! Mostly simple tools, and absolutely doable with nothing but hand tools! About ~$15 for 4 feet of aluminum (share w/ your friends!)… plus fun fiddling in the garage = Winner winner chicken dinner. Soon some flat mounting VESC’s that happen to have a bit more cooling (i hope). I’ll work on the top solution next and show you all what i plan there too.

Hope it helps the next OCD DIY’er who is tired of wobbly velcro’d VESCs!

Night all!

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More progress.

Test fit complete. I need to clean up the pins and some hot glue to ensure none poke into power wire (bad short - easy to avoid). Then i’ll re-shrink and re-mount.

But here’s the goal (at least bottom - still figuring out top heatsink):

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Simple m3 nylon screws and standoffs. you can see a bit of a gap but it tightens down securely and feels really solid!

Super pleased at my hole alignment and fit. just a bit more cleanup and add the heatsink paste and should be GTG!

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It’s really surprising how much power these 4.12 boards are capable of when the MOSFETs have a proper way to remove heat. Any plans for the upper MOSFETS?

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this is my kind of thread. Simple and effective and accessible.

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I have tried thermal pads, thermal paste and heatsink potting compound. Lots of debate over what is best so I will just say potting compound is what I use and recommend. You can get a tube for a few dollars on ebay and it doubles as a good setting compound for stabilizing wires coming out of a jst connector.

With potting compound you can interface with more surface area. Potting the gate, source and drain produces some decent results.

If you go down this road be sure to clean the vesc well before applying any type of coating or compound. Moisture can accumulate in areas with poor adhesion. I recommend using an acrylic conformal coating before applying potting compound to further guard against possible moisture issues down the road.

While we are on the topic, it would be easy to make a breakout board with direct fet footprints. It could be designed so that it replaced the irf7430 and not take any extra space. I wont say it would be easy, you would need some reflow skills and a hot air machine.

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Still thinking on the top FETs. I have a few finned aluminum heatsinks i know will work - the challenge is mounting them reasonably securely without permanent thermal paste.

I’ll play with it some more and come up with something.

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Thanks @chaka! I’m intending to keep this non-permanent so i can remove if needed (and move to another VESC - i have a few).

I know you push the limits, so let me be clear on my goals:

  1. better flat mounting.
  2. improved cooling and thermal capacity (able to load the heatsink for longer uphill run)
  3. be kinda cool, but not CNC cool like yours. DIY cool maybe.

That’s it - simple and something doable w/ handtools (drill press really helps, but steady hands totally would work).

Of course i’m going to go look at thermal potting compounds anyway. I’ve always used arctic silver compounds on my PC’s and know they provide excellent thermal transfer - so i was intending that between FETs and lower plate, and again between upper FETs and TBD heatsink.

I have some conformal coating already - i’ll need to check if it’s acrylic based.

Really appreciate the insight and contribution to my little project man!

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You could make some kind of bridge to go over them and try to transfer the heat through screws to the base. That’s what I did with mine, and it seemed to work well. Then again, literally anything is better than constricting the MOSFETs inside a silly layer of heatshrink!

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Be careful, you don’t want the pins of the jst connector to punch a hole in the power wire. I would add some hot glue to the bottom of the pins or cut them off.

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@JLabs - yep! I just test fit this, but at the start called out i was going to hot glue, then re-shrink to give some protection:

It’s super important, but i also think that if i use a washer to avoid PCB flex/movement - it shouldn’t be able to pressure down on the wires now that they are between the fixed mount and PCB to puncture. I’m still going to clip and hotglue them because it just takes a minute and ensures no short.

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Yeah, thought about some side mount attachment monstrosity… but think i’ll try to stay simple.

If you need to REALLY push your VESC and this extra cooling is make-or-break for you - go buy @chaka’s/Ollin Board Co’s new sexy CNC Direct FET VESC. I’ve held them - they are gorgeous!

If you want some improved cooling for occasional heat/throttling issues - and want a more sturdy flat mount - THIS DIY IS FOR YOU!

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Woops I mostly look at the pictures :smile:

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Well - for folks who find this and want to see what we are talking about (and how to fix).

If your pins under the power wires aren’t clipped the issue is it can pierce the wire sheathing and short - killing your VESC and let the magic smoke out! I also add some hot glue as extra insurance- here’s what it will look like (the two sets of pins i’ve seen pierce and kill a VESC):

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Then clipped (i use some sharp nail clippers or small flush snips):

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Then a small dab of hot glue to cover:

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There ya go @JLabs - pictures! hehehe

back on topic (my thread so i’ll wander if i wanna!)…

Made a few more, and cleaned them up a smidge:

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Then on a @zmoney / Axle VESC (very nice quality w/ upgraded BOM components - just wish it wasn’t XT60 i’m swapping): Already snipped and some glue to protect.

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I’ll work on the top heatsink tomorrow…

Night all!

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Awesome work man. Wish I was still in Sea town i would love to have met up and ridden. Everything you post is stupidly useful both here and ES. Props brother, on yet another helpful thread.

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Fun long weekend and spending a lot of the time in the garage!

Working on this a bit more, I’m trying a couple different setups. Since my stable/bevy of beautiful VESC’s have been pretty problem free (besides a few i killed on the bench w/ 12s) - i’m going to adhere the bottom mount on a few and try both permanent and thermal paste (vs adhesive) on the top.

I double checked all pins are cut flush, hot glue to protect from possible puncture/short (also less likely since flat mount with standoffs prevent pressure), then screwed m3 nylon w/ washers and spacers - finally re-shrinking VESC and cutting out only minimum needed (trying to keep it somewhat protected, but not water or splash proof by any stretch.)

So here’s the mount, and a re-shrinked VESC w/ all my cutouts ready:

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Top
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Bottom (a smidge OCD on the cutouts… i know)

Thin layer of Arctic Silver Adhesive (this is the Arctic Alumina which does not conduct - in case a small bit gets on a leg/trace):

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(quick clamp to give even pressure and let it set (pretty fast - maybe 15-20 min in 70* temp)

In the garage and up way too late, but great Saturday!

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Off to keep it going and get some more projects done!

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Thank you for sharing! I’m going to try this on x2 VESC that I have. Living in a hot weather area will not do well for my poor VESCs.

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sl33py , where are you getting firmware to throw onto your 4.12 VESC? I have two Ollin 4.10 is like to throw on a couple boards but realized that since purchasing I have upgrades computers and now can’t seem to find any of my old bldc folders ( new v 6.0 is bright and shiny though).

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Hi,

Funny I recognize some names from ES here!

Topic here is very important and I’ve been working on finding DIY level cooling solutions for VESC 4xx (I use another VESC type so searching solutions for custom and 6xx too) ;

Now a tip since you have access to a CNC machine, don’t bother gluing Alu on top of the plastic. Thermal resistance of the casing is very high, you will gain nothing by cooling it no matter the heat sink. You must cool the PCB and the solder areas. Cooling the metal on side of the FETs also works.

Using a fan to direct air through this area is also valid to gain few degrees.

I’ll post my solution once I’ve gotten the parts tested (I’ll serve as self Guinea pig). Keep on the good job!

ÉDIT : I forgot, you better be cautious about arctic silver. In couple years it will lose its thermic property and become hard as rock.

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Hey @Vanarian - yeah i see a lot of the folks from ES here too!

I cut out the heatshrink to expose the top of the FETs - so these are in direct contact, not to the plastic. Am i missing something? Look at pics above and you’ll see where i coated them w/ Arctic alumina (not Arctic Silver).

I wish i had access to CNC - not quite yet. All done by hand and you can see some rough edges as a result!

I’m using the alumina instead of silver so that it’s non-conductive - in case a bit of the paste touches a leg or trace.

It seems to help, though i haven’t tested side by side w/ one without heatsink yet. I’ll have to give that a shot and see if it makes any noticeable improvement.

Thx!

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To me on the pictures it seems that you put the alumina layer on top of the individual black plastic cases of the FETs? These small boxes have a thermal resistance very high, that’s what I was talking about.

For example I don’t have heatshrink on my VESCs, I should put some to avoid hazardous shorts though.

How is the durability of Arctic Alumina?