Added:
4 connectors for thermistors to FET gates for precharge and discharge, and power resistors
Comparators, and an optoisolator for thermistor circuit
2 FETs on the isolating DC-DC to turn off the isolated side through firmware (normally on/closed)
2 connectors and circuitry for fans to cool motor controllers
LED on discharge circuit
Additional inputs to MCU for data logging
Changed:
Power resistor values
Additional thermistor output to shut off precharge (aside from precharge complete)
Components added to library:
RES 1K OHM 15W 1% TO126
RES 5K OHM 25W 1% TO220 (Since discharge FET overheated last comp, this is a pretty conservative resistance value. Can be lower.)
IC MUX 1 Circuit IC Switch 2:1 3Ohm SC-70-6 (not used)
Footprints added to library:
RES TO-126-2
RES TO-220-2
IC MUX 1 Circuit IC Switch 2:1 3Ohm SC-70-6 (not used)
New functionality:
Precharge will stop if any of the precharge/discharge resistors or FETs overheat (around 90 C). Firmware will get a signal of which part is overheating.
Ability to shut of isolated DC/DC, turning off isolated side of board. Will prevent precharge and allow discharge without shutting off entire board.
***
Upon further review, this was already possible through PA9, which enabled vbat_precharge_sw to the isolated DC/DC.
The circuit to shut off isolated DC/DC added isn't entirely useless. The PA9 enable pin enables vbat_precharge_sw. I used that to power a lot of the non-isolated stuff like overtemp comparators and fans. So we still have functionality in keeping those on to log with the MCU.
I think it also powers the contactor sense so it'd be nice to have that on whenever the board is on.
After further discussion, it is decided that two load switches would be the better alternative.