Is it possible to use a 20s BMS as 18s?

[dfarning]

Sorry if this is a dumb question...

I am building an 18s lipo battery pack for an endurance vehicle. Is it possible to use only 18 balancing lead of a 20s BMS and leave the last two either floating or ground? I was unable to locate any 18s Battery Management Systems.

thanks

 

[fechter]

It totally depends on the BMS. I have seen many that will work with fewer cells by not using the highest ones and tying all the unused wires to the top cell. Don't leave the wires floating, they will pick up noise and false trigger.

Some BMS designs will see the unused channels as a fault and shut down.

 

[dfarning]

Thanks,
I'll make some selections and then contact a few vendors directly.