my first big project - BMS - is it possible?

Thanks for the advice.
I understand the concern, and it s certainly something Ill remember.
I could incorporate a check if voltage ==0 after opening the last and before closing the next relay.

For security reasons, i plan to test the system on a much smaller 20 cell nimh pack.

I have no idea what the 4514 decoder chip is/can do, but Ill look in to it.