Contactor Control

[johnsongt350]

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?

[Bigpie]

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

[johnsongt350]

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

[johu]

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