On Monday the new PCBs for the power controller arrived and this past week has been spent assembling and testing the board. The TL:DR is that testing is nearly complete and so far no major issues have been found. These new boards implement a new bus control architecture along with lots of little tweaks and updates from the v1 board aimed at making it more robust.
Despite the success there were a few setbacks. The biggest issue found was that I was missing diodes on the bus override switches (oops), so if you left the switches in the ON position but were in override mode, it could result in some busses being erroneously turned on in specific scenarios. This is easily fixed by adding the diodes in series with the switch headers which will will connect the switches to the board. The second issue was the lack of pull-down resistors on the bus control outputs. This was a bit of a calculated mistake, as I planned for the LEDs to function as the pull-down, although I neglected to realize that unlike using a normal diode for pulldown which brings it pretty close to 0v, the LEDs forward voltage is way higher, so it only pulls down to ~2.3v, so not a great pull down after all… After some testing I determined only ~10uA was needed to pull it to ground, and when testing with the actual relays connected it was no issue and didn’t result in any erroneous activations. So both problems turned out to be no big deal, although certainly if a v3 is ever made they’ll be included as fixes.