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DC-DCHeatSink

Intro

I recently had Ron Anderson rebuild my Kilovac motor controller. In the process, he changed the heat sink and enclosed the whole thing in a shroud which made it impossible to re-mount the DC-DC converter on the old motor controller heat sink. This was probably a good engineering choice on his part, but it was an inconvent thing for me, because it forced me to come up with another way to mount the DC-DC. He also suggested that I put a better heat sink and forced air cooling on it. He pushed me toward buying Vicor's heat sinks, which might also be a good idea. But I didn't want to wait for Vicor to deliver them and I didn't want to spend the money. Furthermore, I would still have had to build my own mounting bracket.

A Cheaper Solution

I experimented with welding and brazing fins to a flat plate. Those turned out to be bad ideas. A better idea was to buy a couple of old Pentium II processors ($2 apiece used) and take the heat sinks from them. I fabricated a bracket that positioned the DC-DC next to the motor controller in the high-voltage compartment in the back of my (hatchback) Sparrow. Here's a picture of my bracket with the DC-DC on it.

Details

I cut the old processor heat sinks to fit the holes in my bracket and riveted them to the bracket. (I counter-sunk the rivets, so that they didn't hold the DC-DC off the mounting plate.) I put two little fans pointed right at them and ran the power to fans through a little button thermostat, so that they'll turn on only when the temperature starts to go up. (I didn't want my battery drained by constant cooling.) Here's a picture of the back of the bracket with everything mounted.

Jake Oshins