20s bms on 18s battery for charging only

[dice2jr]

Hi all, my name is guy.
Me and a friend of mine have just finished fabricating a new electric buggy chassis and have assembled everything together.
We are using an 18s 28 ah lipo battery(3 * 6s 28 ah batteries).
the motor and controller are both capable of over 250 amps and we are running them that way.
I'm searching for a simpler solution for charging. Right now I charge the batteries one by one at 1c.
That takes me about 3 hours to full charge and switching twice in the process.
as it happens' i have a 20s BMS capable of 45a charging current.
I was wondering if it's possible to use a 20s BMS on an 18s battery only for charging.I know that discharging through a BMS that way will not be possible. i have searched the forum and not found any information on charging that way.

any help will be appreciated.

thanks

 

[john61ct]

Depends on the BMS, some require modding.

Not sure why charging vs discharging would be a different answer though.

 

[fechter]

Post a picture of the BMS. Many of them are easy to use with fewer cells. Some are not.

In general you wire starting at the B- end and tie the unused wires to the top cell wire.