busbar length charge/discharge battery bank balance

[ben22]

hi, im looking for advice about my battery configuration in regards to cable/busbar length and the balance of the battery over time

here is what i have so far:



here is a diagram of how im thinking about connecting the cells:



as you can see, i have 6 cells in parallel and 7 off these packs in series to make a ~48v battery
i have arranged these in 3 layers of 14 cells bolted together so they fit my cabinet, with space above for the inverter.
as a consequence of this they have to be wired a bit oddly with 2 cells from each layer forming one of the parrellell packs
after some reading i have realised this may cause a problem due to the uneven lengths of wire/bussbars
the orange busbars in the diagram have been made already from 20mmx4mm copper, the green connections in the diagram are yet to be made
the battery will have a bms either daly or ant bms.
can anyone offer any guidance about how my battery will perform, which connections should be equal in length/resistance, if the bms will be able to take care of any imbalance caused due to the configuration illustrated,

Regards Ben

 

[Higher_wire]

Wire the cells in a row like shown (ignore green and yellow lines). Second life cells are going to have different IR regardless, so unless you've tested at 1kHz AC and balanced each string by capacity and IR you're going to have some imbalance. This way makes positive and negative leads close to the same length and minimizes differences between positive and negative conductor length at each row end.

 

[ben22]

ok great thanks, i will reconfigure.

 

[ben22]

heres some pics of how the pack is now, i have used some bus bars from the leaf pack, they are thinner so not perfect

 

[ben22]

can anyone give me advice on dc breakers/inverter/bms for this battery bank

here is what im looking at :

i have seen people use a 1p breaker only on battery positive, i have seen people use a 2p breaker on battery positive and battery negative

should i use 2 x 1p breakers one between battery and inverter positive and one between battery and solar controller positive or can i use one 2p breakers one leg to inverter and one leg to solar controller, or should i also have a breaker on battery negative?

what kind of breaker/wiring is most effective?

inverter is 6kw cont. 18kw surge :

as for bms, im looking at this :

i figure 300amp components should be adequate 300x48=~14kw

this is the first offgrid system i have built, if anyone can see anything wrong with the components im looking at please let me know

regards Ben

 

[houseofancients]

I'm using similar breaker, always 2p.
Make sure you understand the specs, and that they are bi directional