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Is this 24V 2P4S Arrangement a Problem?

natec

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Jan 28, 2021
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I'm looking to build a 2P8S 24V battery out of the EVE 280 cells. This geometry fits best in my van design. It seems like it should be fine, but I haven't seen it any any of the other designs on this forum which makes me think I'm missing something.

(if you are curious, the cells will be fixtured between two 1/16 aluminum plates with 15 members of 1/2ish inch all-thread preloaded with belleville washers to get the recommended 12psi) (also, the cell groups will be insulated with kapton tape)
 

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It's fine.

I recommend you double-bus bar the circled area. You have two series interconnects between all other cell groups, but only one here.

1612280836286.png

IMHO, 1/16" sheet is too thin. 1/8" should suffice.
 
Thanks for taking the time. I actually meant 3/16, but I'm happy to go with 1/8 if thats enough. I'm also planning to jump between those end terminals such that each cell has equal length to the other side and resistance is matched all the way along.
 
1/8 is thinner than 3/16, so stick with 3/16.

Simply adding a double bus-bar between the two cells circled will suffice.
 
Since you commented on the plate thickness, I thought you might be interested: I did the math for 1/8 Al, 3/16 Al, and 1/2 plywood. I'll definitely be going with 3/16:

github.com/natecostello/van_two_point_oh/blob/master/electrical/battery/Battery_box_design.md#plate-thickness

Nice write-up. That makes me very comfortable with the 3/4" plywood end plates.

I tried to find a simple tool that would give me the deflection of a plate of aluminum that I was thinking of using for a table. What I could find was beyond my understanding, or it was behind a paywall.
 
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