Model 3 BMS Faults with EVControls ECU

[Maddan417]

Hey everyone,

My coworker and I are in the middle of putting a model 3 drive unit and pack into a VW bus. We’ve done model S swaps before but this is the first conversion with a full M3 system.

We stacked the two other modules on top of the center modules and got everything into the van. We’re using the EVControls T2C with the model 3 battery add on.

After updating all the firmware we are getting some internal faults that we can figure out. Those are listed below.

BMS_a001_Pack_Config_Mismatch
BMS_a050_SW_Brick_Voltage_MIA
BMS_a099_SW_BMB_Communication
BMS_a107_SW_Stack_Voltage_MIA
BMS_a156_SW_BMB_Vref_bad
BMS_a161_SW_DI_Open_Request
BMS_a170_SW_Limp_Mode
BMS_a171_SW_Stack_Voltage_Sense

We’ve checked the BMB boards and all the sense wires are intact. Went down the sense wire connections and they add up to the module voltage. We did extend the BMS wires that run to the penthouse but confirmed continuity and less than 1 ohm resistance. Contractors are closing and were able to drive the motor but the bms is in limp mode. We’re seeing cell voltages for seemingly random cells ranging from 0 to 107 with big chunks missing .

This seems like a communication issue to me.

We’re at a loss here. The battery tested fine before it was shipped to us.

[tom91]

Did you test it worked with the EV controls before modifying the battery pack?

You sure you have the BMBs wired exactly as per layout in the tesla pack? Please provide pictures and diagrams.

Also note, adding URGENT does not help. Please provide more info on who you are and where you are based.