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Chris's Build Thread
They huge! But they pretty! Big Grin

This is still considering an ATS. You are Automatically Transfer Switching from one source to another. The one thing we (I) was missing, was the direction in which you were sourcing. I think you were going from Mains to Battery and back to Mains if there was a problem on the line. Didn't realize you were going from Battery to Mains when the batteries get low. Still ATS, just using 1/2 of what other use it for Wink
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So I got some batteries today...

This is my prototype pack:

I made a pack that had about 7 cells in it, But as I was tightening the nuts down I noticed smoke. So I frantically took it apart and found this:

I have no idea what caused this. I am not sure on what the washer shorted out on? Thoughts? Maybe I had the cell in the pack backwards? I was in such a hurry to break down the pack I didn't check for anything weird.
looks like a puncture from a washer
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I talked to someone familiar with these cells. There is a clear insulating layer on the outside of the cells, and the pouch is made of metal. So the negative and positive on the pack shorted briefly. Back to the drawing board
I am still working on a way to connect these batteries in packs. I made a mistake of thinking washers would work. Technically, I still think they would if I make sure the 'rounded' side of the washer to contact with the battery, since then it wouldn't cut into the insulating layer. However practically it will take something like 24000 washers in all for 1050 cells to make my bank. Currently I am thinking about using 3/8" hard copper pipe cut to height between cells. That has a decent wall thickness with a 1/4" inner diameter. Its fairly cost efficient as well. Any else have any ideas?

I am trying to not lose hope here on these batteries, and I really hope I didn't make a mistake with these batteries, as SLA batteries are starting to look real good right now in terms of complication of implementation.
You could go Nut, cell, Nut, Nut, cell, Nut etc.
Might be easier and lighter than all the washers.
You could more easily control the cell contact.
How about plain or threaded stand offs ....

(10-27-2018, 08:38 PM)Bubba Wrote: You could go Nut, cell, Nut, Nut, cell, Nut etc.
Might be easier and lighter than all the washers.
You could more easily control the cell contact.

I was thinking about this too, just might take a long time plus the issue of having appropriate spacing between the cell terminals/cells themselves.

(10-27-2018, 10:18 PM)Sean Wrote: How about plain or threaded stand offs ....

The problem I found with those is getting the correct height. I need 11/32" tall with at least a 3/8" hex width.

I am still poking around at both options though.

I had an idea of having bus bars made for the positive and negative side, each terminal can then be bent and screwed into it using M6 machines screws. Then use the Acrylic on the ends with the threaded rods for compression. The rods would go down the short sides instead of through the terminals obviously.

I whipped this up in CAD:
The professional ones I have use a Circuit board and the cells (much like the board your thinking of) are strapped applying pressure to them.
The problem looks like you need to extend the exposed tab part so you don't risk pinching the pouch outer layer.
Maybe use some thin copper sheet eg 30mm x 50mm, fold in half (on middle of 50mm) + punch/drill hole for rod.
Then solder copper part to cell tab.

I have some similar pouch cells & they are assembled with tabs through PCB slots, folded 90 deg & soldered flat. 4 cells to a PCB.
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