diy solar

diy solar

Insulation material between aluminum case cells.

Leakage voltage? That would be a short. I've heard of current leakage but that's different. The voltage I read was full cell voltage at the case. I can't find a good picture of the construction online. I'm thinking that when the cell is built the cathode is on the outside and touches the case. Either that or it is an intentional physical connection. I can do a low amperage test. It would be interesting to do a high amperage test on a battery nobody cares about. Might be a cool video too.
Did you look at the thread I linked to? You can also look at the spec. sheets and see if you can find anywhere in any of them that the case is tied to the positive terminal of the cell. Measure the current between the cell negative and the case and tell us what you see. @upnorthandpersonal shorted the cell negative and the case and nothing happened. It might be best to refer to it as leakage current...I don't know. When I get a chance I will test for myself and report back.
 
A better material would provide some thermal barrier in addition to insulation. If one cell shorts and goes into thermal runaway it can prevent a cascade to other cells.

One idea is to use cement fiber board used for shower walls. Easy to get at Home Depot. There might be better options.
 
The voltage I read was full cell voltage at the case. I can't find a good picture of the construction online. I'm thinking that when the cell is built the cathode is on the outside and touches the case. Either that or it is an intentional physical connection. I can do a low amperage test. It would be interesting to do a high amperage test on a battery nobody cares about. Might be a cool video too.

That can't be happening by design.

This makes me glad that I built by cell compression frame out of wood and covered the threaded rod with plastic sleeves.
 
The aluminum case should be floating. The plastic battery pouch should isolate from the aluminum case.

Only other way is if there was a short from one of the terminal connectons to case. That would likely be a flexing for the tabs coming from top of the pouch to terminal, bowing out and touching aluminum case when the top terminal strip was pushed down to top of case..
 
Since I've been looking at battery system code in the NEC book for other reasons today, I thought I would chime in with the relevant code section.

1607914748225.png

It says that all it takes to trigger the requirement for insulating battery supports is for a battery case to have a voltage on it. This could just be incidental to the battery design, but it still appears to cause insulating materials required for a code compliant installation.
 
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