80A & 95A Current Tests
I did some current testing this morning using the new Power board and the last version of the Logic board. The new Power board outperformed the previous version of the Power board and did so without an expensive and difficult to work with copper bus bar. The “secret” to this is two fold. First, I more than doubled the amount of copper foil on the PCB which is now equal in cross section to a 6 AWG wire. Secondly, and more importantly, I’ve increased its thermal mass and ability to radiate heat with the addition of the screw down power terminals. These terminals are massive, are well thermally coupled, and will be exposed to air outside the epoxy and will act as radiating surfaces to push the heat off the Motobrain. Below are photos of the unit pulling 80A and achieving temperature stability at around 62C (better than the previous board which got to around 80C) and the board pulling 95A and leveling off at around 74C. These tests were conducted for about an hour and no significant temperature change was observed after about 15 minutes.
The next steps are to build up some new Logic boards, confirm they work, and mate them to new Power boards. Then I will need to do a little firmware/software update for compatibility with the 4 new analog inputs. Finally, I’ll epoxy them up and do more thermal tests. Assuming these are good, I’ll box them up a ship them off for 3rd party testing.