Lots and Lots of progress on the BMS... Version 0.3 has shown up and been assembled and I am actively testing with it. Unfortunately there were a few mistakes, including the switch FETs being backwards... awkward... so I have started work on V0.4 but will probably wait a while before letting it loose to the fab. I conducted high current (50A) testing on both the sense resistor on the low side as well as the MOSFETs on the high side (long story short with the backwards FETs is they still act as a switch, but a stuck on one) and had fair thermal results with the new thicker 3Oz copper in all 4 PCB layers. Here is one of the first PCBs hot off the hot plate after being pick and placed by a new machine I got called "Boarditto":

I am now deep in the process of writing some basic software that actually deals with the protections that this BMS will provide. hoping to provide more details on that soon. Once I get the code in a somewhat stable and working place over the next few weeks, there is lots and lots of electrical testing and validation to do on the hardware.