PS port: I connected wires 1 and 6 (soldered to the PS battery connector PCB) with a small protective resistor, and the error message disappeared. It seems that pin 1 of the PS serves as a range selection switch: Open = 11-15 VDC range to GND = 40-59 VDC range Delta (EB) port: Added a 1kΩ resistor between pin 4 (12V) and pin 6 (GND) in the EB connector to pull the enable line low. This signals the BMS to connect the internal battery to the EB port.