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Battery bus bar help

Mondo

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Joined
Dec 7, 2020
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So I have cells, and I forgot to ask for extra bars. It’s going to take a couple weeks to get them, so I’d like to make my own. sadly, all the threads here, and charts, accomplished only making me question my intelligence.

I have 2 options right now:
- decent thickness zinc plated “mending plates” from Home Depot
- some 0.025” copper sheets from the “hobby” section

the Home Depot plate metal looks EXACTLY like the bars the battery manufacturer sent. In a moment of bravery/stupidity I said “why not try”, and hooked the cells in parallel (to balance), and tested just about every spot on the bars to ensure consistent voltage. But I was too afraid to try a load. Warranted?

the copper sheets I plan to cut down with tin snips to 1” x 5” x 0.025” strips. I have a 2,000 watt inverter, and cells (3.2v x 280ah) will be arranged as 12v x 560ah. Is one strip that thin ok? Do I need to double/triple/more?

am I ok with just the cheaper zinc plating? They are way stronger, at about 4-5x the thickness.

photo of copper label.
photo of manufacturers bars on left and mending plates on right (I’ll remove stickers)
 

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If those mending plates are steel, I think I would avoid them.

You can flatten copper tubing and drill it.
 
Someone mentioned copper pipe hanger or "plumber's tape"
That should make great busbars, could laminate several for flexible cell interconnects of any ampacity desired. Bent shape would allow for expansion.
Only issue is copper on aluminum; suitable corrosion inhibitor or a layer of tinned aluminum or tinned copper on bottom would be good.
And of course remove native oxide from aluminum terminals.


"mending plates", zinc plated steel. Not so great, although they would work at low current (e.g. for balancing)


Tinned steel is used for some battery connection, as fuse-per-cell.
 
So I ended up ripping the terminal posts out of a cell, and ordered another set of 4, because the company wanted more than half the cost of 4 to just get 1. Had them throw in the nice copper ones they make.
I also ordered some copper bar via Amazon. Went to local mom-and-pop hardware store, and they cut and drilled it all nice for me.
 

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So I ended up ripping the terminal posts out of a cell, and ordered another set of 4, because the company wanted more than half the cost of 4 to just get 1. Had them throw in the nice copper ones they make.
I also ordered some copper bar via Amazon. Went to local mom-and-pop hardware store, and they cut and drilled it all nice for me.

bar on Amazon: https://amzn.to/376SahF

Hardware store that did the side bars for $14:
A-1 Hardware
(310) 559-9594
 
So I ended up ripping the terminal posts out of a cell, and ordered another set of 4, because the company wanted more than half the cost of 4 to just get 1.

You're not the first. Have you read the threads on stud repair?
Helicoil and JB Weld have both been successful.
Various talk of torque wrenches too.

Have you seen the other thing people are doing to cells? (Shorting them with a wrench, or shorting the pack externally and exploding a busbar. Either way, cell terminal turns into a puddle.)
 
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