MBDT and MC33771C - Abnormal cell balancing and BCC does not go into sleep mode

[Poley]

I have found something very weird when testing the board tonight. I set up balancing to test that part of the PCB through the MBDT. Random cells go up and down in voltage when enabling balancing (Up in voltage is really weird) I have attached an image of the cell voltages when I set each cell to balance and off one at a time.

Also, cell 6 and 8 are constantly discharging. These cells are old so I will swap them out to see if it is the cell of the board.

It would be good to know if I am doing anything wrong in terms of balancing control as well. Also, my CMU does not go to sleep after it has started communicating. Using the sleep blocks in the MBDT does not stop communication or turn off the BCC, all it does is add a 15% delay to my application code timings. (My CAN transmit goes from 100ms to 115ms). Swapping the master to the dev board with the MC33771C GUI code does put the BCC into sleep mode, so looks like it is the code.

@mariuslucianandThis is critical. Please could you let me know if you have any ideas on this? Thank you!

[zctbjy]

Have you ever used the charge of 33771CTP1AE

Collection function? I can read the data now, but it is incorrect

[Poley]

can anyone help with why I cant put the BCC into sleep mode from MBDT? This is a critical issue. Thanks!

[Poley]

Does anyone have any ideas on this please?

[Poley]

So, the 2 cells draining was a short on the MC33771C pins which was putting those pins in a continuous balancing state.

Balancing is still super weird, the cell next the cell you want to balance goes up when the cell balancing goes down. Is this jue to reading cells while balancing? Do the MBDT blocks not stop balanceing for a few ms to get a reading?

The other issue is the sleep mode not working. Could you please show me what you would normally use in terms of block sequence as whatever I put in doesn't work. The GUI does it so I am sure that the CMU can go into sleep, it is just figuring out what blocks to use and when! Also, I can't use the TPL disable block, everytime I do my code fails to build:

Thank you! I have attached latets model.

[Scottrobson]

Hii,

It's advisable to double-check the balancing settings and ensure they're configured correctly in your MBDT. Regarding the constant discharging of cells 6 and 8, it's a good idea to replace those old cells to rule out any issues with the cells themselves.