I have a 2k watt inverter, will two Overkill 120A 12V 4S BMS's work with two separate battery packs?


New Member
Nov 10, 2020
This question may have been answered (potentially many) times before but I'm struggling as a noob. I have two separate 4S battery packs (8 cells in total) in a 12V system. Each one will be equipped with its own Overkill 120A 4S BMS(es?). I have a typical off-grid, camper van DC load and a 2000W inverter. If each other the packs are connected to two 300A fuses is that okay? Will the two 120A BMS units be enough to cover the load?

Bonus question: How would I connect these to the Victron Lynx Distributor battery in side? I have a Master Disconnect Switch and Battery Monitor shunt that I would prefer to just have one positive and negative wire. Should I use bus bars rated for 300A? If that's the case, would I even need to have two fuses or could I fuse the entire bank (pack #1 and pack #2 combined at the bus bars) "after" the bus bar, on the side towards the Victron? (I'll attach a schematic.)


  • Electrical diagram v4.jpg
    Electrical diagram v4.jpg
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Apr 24, 2020
Somewhere South of Denver
It will work great! I have two 4s batteries with the Overkill Solar BMS.

I cheated and used a single Class T fuse and battery disconnect for both batteries. The more correct method is to use one Class T and one disconnect switch for each battery. I can't speak to the Lynx connection question.

My common bus bars are rated for 250 amps. My loads are well under that limit.