BMS 8S

[RRRRRRRRRRudy]

I am modifying my RV battery to use LiFePO4. For now I am waiting from alibaba on 4 3.2volts 280ah battery and a BMS 4S 150a.

My questions:
- next year I will add 4 more battery to my system and want to keep it 12vdc. So I have found here on the forum that I can use the same BMS 4S with 8 battery. Putting them in parallel (by 2) then in series. Is it the best option or do I have to change my BMS to a 8S 12vdc (if that exist) ?

 

[Steve_S]

12V Battery pack requires 4 Cells and one 4S BMS. (8S is for 24V)
To add another battery would require 4 more cells & a 4S BMS, then installing in place in Parallel.
Each battery should also get an appropriate sized Fuse. I personally favour MRBF type fuses

MRBF Terminal Fuse Block - 30 to 300A - Blue Sea Systems

Easily and economically satisfies ABYC 7 circuit protection rule by mounting on a 3/8 battery post, battery switch or bus bar.

www.bluesea.com

 

[JRG]

12V Battery pack requires 4 Cells and one 4S BMS. (8S is for 24V)
To add another battery would require 4 more cells & a 4S BMS, then installing in place in Parallel.
Each battery should also get an appropriate sized Fuse. I personally favour MRBF type fuses

MRBF Terminal Fuse Block - 30 to 300A - Blue Sea Systems

Easily and economically satisfies ABYC 7 circuit protection rule by mounting on a 3/8 battery post, battery switch or bus bar.

www.bluesea.com

Not sure what's wrong with the drawing he attached, should work fine as he proposed.

 

[Steve_S]

2p4s will work with a 4S BMS but offers zero redundancy or failover. It will work BUT must have the exact same cell types (Make, Model & Version) if you are expanding a battery p[ack from 4 cells to 8 cells. If the cells are differen, even versions of it, issues WILL arise and won't be a simple thing.