Mixing wires and bus bars in a DIY battery pack

[frostyllama]

I'm building 2 24v 8s battery packs with 280ah EVE cells. Each 8s pack will have it's own 8s overkill BMS. I've picked up Milwaukee packout crates for battery boxes.

It seems like good practice to keep the cells as close together in a pack with equidistant bus bars of the same material. However, with the packout I've chosen, it's easier to place 2 sets of 4s cells on opposite ends of the box. I plan on running a wire between them about 6-8 inches long to join them as a single 8s pack. This wire is about twice as long as the other bus bars in the battery. Is there anything wrong with connecting the battery like this?

 

[ArthurEld]

I'm no expert but the longer wires probably should be bigger than the busbars.

My battery pack has some cells farther than others. I used bigger busbars for the longer distance.
Mine are only 1 inch different.

Yours are much farther and you are using wire instead of a busbar. My guess is that your wire will need to be really big. Like 2/0 or 4/0

Other people will probably have more info for you.

 

[Supervstech]

It depends on the load placed on the battery.
If you have hundreds of amps being drawn, he connecting wires will need to support that... and you want as little voltage drop as possible on the bank, so you would need larger wires than normal for the load.

 

[frostyllama]

It depends on the load placed on the battery.
If you have hundreds of amps being drawn, he connecting wires will need to support that... and you want as little voltage drop as possible on the bank, so you would need larger wires than normal for the load.

How do I calculate the size? I've got 1/0 wire on the way which should support well over 100 amps for the distance. The bus bars are oversized to support up to 150 amps but the BMS is only rated for 100 amps. Is 1/0 large enough?

 

[ArthurEld]

How do I calculate the size? I've got 1/0 wire on the way which should support well over 100 amps for the distance. The bus bars are oversized to support up to 150 amps but the BMS is only rated for 100 amps. Is 1/0 large enough?

Sounds good to me