openinverter forum

Question I have the Simpbms and simp charge running in my EV conversion. I am also using the open inverter with LDU. I was controlling the contactors with the inverter and was advised it may be a good idea to control the contactors with the Simpbms. I ran key on power to the simp J5 connector pin #1 and then from J4 connector pin #4 to ignition contactor to start the sequence. The inverter doesn't seem to like this as I hear the contractors click and after about 5 seconds I hear a third click which kills power. Any suggestions?

Do not allow the BMS or inverter to open the contactors while the motor is spinning. This will kill the SDU or LDU inverters.

Maybe I wasn't clear in my explanation. I am referring to just key on power. The vehicle is in neutral.

5s sounds like the precharge timeout. After 5s the inverter needs to see udcsw/2 on the bus caps, otherwise it turns off precharge. Not sure how you wired it up