Overthinking parallel battery wire length ?

[JoeHam]

More specifically, parallel battery wire resistance which is approximated by wire length.

I have an older EG4 100Ah 48V nominal battery that I plan to parallel with a DIY battery made of 16s CALB 100Ah cells.

I have about 3 feet of 2AWG on the EG4 to the busbar.

On the DIY, the situation is complicated since I will have a 100A circuit breaker between the battery and busbar. My Klein CL 390 seems unable to accurately measure the resistance in the breaker with wire combo compared to the wire alone.

Am I overthinking this and trying to pick fly poop out of the pepper or is this a real concern?

I’m tempted to shorten the positive wire with the breaker as much as possible to account for the additional resistance caused by the breaker and two additional connections and call it a day but……

 

[time2roll]

Keep each battery loop the same total length to the bus to keep the parallel batteries sharing the load and charging in a balanced matter. Individual connection can be different as long as the round trip is the same. Yes there might be some extra wire to tie up. This is even more important with LFP than lead-acid due to the lower internal resistance. Never going to match perfectly and still worth the effort to match as close as possible.

 

[JoeHam]

Keep each battery loop the same total length to the bus to keep the parallel batteries sharing the load and charging in a balanced matter. Individual connection can be different as long as the round trip is the same. Yes there might be some extra wire to tie up. This is even more important with LFP than lead-acid due to the lower internal resistance. Never going to match perfectly and still worth the effort to match as close as possible.

How should I account for the extra resistance of two connections and a circuit breaker in just one of the loops though?

That resistance could equal a couple extra feet of wire in the loop, right ??

That’s what I am trying to compensate for to get a better match.

 

[time2roll]

Not sure why one battery has a breaker and not the other.