MSXI had issues with LV power distribution.
- Not enough granularity on LV power control resulted in powering too many things off the auxiliary battery.
- Current capacity of the deviceNET cables was a concern.
Power Granularity
There are regulations on what can be powered from the auxiliary battery. At most, we should be powering the power distribution board, main battery relay (temporarily), driver ventilation?, and the BPS. If the BPS faults, it can additionally power the battery ventilation fans and trip indicators.
Since our primary trip indicator is on Themis (over CAN), we need to keep Themis active on faults. Since the motor controllers should not be connected on fault, the additional power draw should be minimal.
Other LV power systems (ex. rear-view camera) should be powered on a separate line.
Current Capacity
Note that splitting the power distribution into multiple dedicated lines will help with current capacity issues.