Lifepo pack insulation

[AgGuy]

I've built a 240ah pack and am getting ready to put it into the chair.
Do I need insulation between and around each cell ?
Currently have solid buss bar connections. Should I change to something flexible?
Thanks!

[LROBBINS]

Yes, you do need insulation around and between cells - the thin vinyl wrapping is too easily punctured and touching the metal of one cell to another is a short through which enormous current will flow.

Burgerman greatly prefers connecting cells with flexible wire and soldered on ring terminals. I'm not completely convinced IF the cells are secured so there's little or no movement of the cells one with respect to another. In that case, bus bars, especially those with a bend in the middle to provide some vibration resistance, may stay nicely connected. The bus bars must, however, be plated or tinned; bare copper will oxidize very quickly and that green stuff is not conductive. I have one chair done with stranded wires and one with bars so I'll eventually know if one gives more problems than the other. I do expect both to stay well connected for years.

[Burgerman]

Yes, you do need insulation around and between cells - the thin vinyl wrapping is too easily punctured and touching the metal of one cell to another is a short through which enormous current will flow.

And underneath.
And around the outer edges.

The stock thin plastic sleeve they come wih is OK if they are used in a static setup such as solar or standby system where theres no vibration. But not in a chair that gets bumped down curbs and rattled around.

[ICEUK]

I 3d printed my own battery boxes, much better job than taping batteries together or pieces of insulation


https://www.amazon.co.uk/photos/share/p ... 0FFsMtdXwq

https://www.amazon.co.uk/photos/share/U ... R6nePUl4SP

[shirley_hkg]

Gum fish / gasket paper between cells , and all are contained in an U-shape plastic duct .

[fishinjunky]

These should work for insulation. Disposable cutting boards
Crown 50 Count Premium Quality Disposable Cutting Boards ~10 Inch X 13.5 Inch Disposable Sheets For Kitchen And Commercial Use ~ Patent Pending ~ Recyclable Disposable Cutting Board Sheets https://a.co/d/fsL3JDx

[swalker]

I wrapped each cell in fish paper (special paper for insulating electrical devices). You can find fish paper at digikey, mouser, amazon, etc. I bought from digikey. I don't remember exactly which one, but it was something like this: https://www.digikey.com/en/products/det ... 560/257752

I then shrink wrapped each cell in this shrink wrap tubing: https://www.amazon.com/gp/product/B07FX ... UTF8&psc=1

I used a heat gun on a relatively low setting to shrink the shrink wrap tubing.

This worked great for me and I plan to use the above approach for my next lithium build.

You can see my build thread here for more information: https://www.wheelchairdriver.com/board/ ... f=2&t=8642

Steve

[Burgerman]

Most thin film stuff works. Even thick polythene bags around the right size. Or a few turns of duct tape adds enough extra protection.

A 230Ah cell is 172 x 50? =225 So a 230mm wide bag would be a tight wrinkle free fit. They would be 100mm too tall, so would need trimming. These are very tough heavy duty bags.

https://www.transpack.co.uk/heavy-duty-polybag-229x305

Amazon have 400g 10 inch or 250mm x 300 ones, that fit 174 x 55 deep cells.