A BLDC motor from an alternator! That's awesome!
The copper bus bars (well, bus bar until I cut it) and heat spreader came yesterday. Commercially pure copper. 99.9%. Very high conductivity. 101% on the conductivity scale. Also about 390 W/(m*K) thermal conductivity, compared to 167 W/(m*K) for 6061 Aluminum, which is all the welding shop near my house sells. Diamond can have over 2000 W/(m*K), but that would be sort of expensive.
I'm sort of angry. I tried to order some of the controller parts. I ordered 25 of the new fancy 200v mosfets (to get the bulk discount), and they only had 6 available, so 19 are on back order, and will be shipped MARCH 21! I am glad I was wearing flame retardant material, cause I was real mad, way down deep!
I found the perfect (at long last!) dc-dc converter for the inside of the controller. Otmar (the Zilla Otmar) helped me out with that. He had used quite a few of the same ones that I had just ordered, and told me they kept failing because the isolation voltage was too low, so he suggested I use the DC-DC part that he's going to use in a new High voltage project he's working on.