Don't glue your 18650er batteries like I did

Just wanted to say that I glued a battery pack together and then decided to talk it apart again because it was not perfect, well that was a mistake:

IMG_20181014_212855_HHT IMG_20181015_010236

As you can see the insulation is messed up leaving the negative pole exposed. So never ever do this, it’s a huge security risk. To be honest I am a little bit surprised the insulation is so fragile. Imagine this happens while driving.

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cell rewrapping is a very common thing for this exact reason.

one could seek out lower temp hot glue which tends to have lower tencile strength but then it’ll be a less tightly bound pack.

also, dime roll wraps are perfect fit for 18650 cells but they kind of act as insulators trapping heat.


It is entirely not intended to act as insulation. The plastic wrap is nothing more than that, a plastic wrap. It is not temperature rated or durability rated. If it was actually insulation then it would resemble shrink tubing, not thin shrink wrap.

You should isolate your P groups from one another.

And as @thisguyhere said, lower temp hot glue will help you, but nothing beats silicone.


Most battery builders recommend natural cure clear silicon…

Permatex 80050 Clear RTV…

I honestly think hot glue is fine if you heat shrink each P group.

I’m also dealing with this. I’m reparing my 10s4p pack and this happened to. I wrapped the whole cell in electrical tape and used fishpaper. Idk if that’s a good to do but I don’t see why it wouldn’t ? If I’m wrong please someone let me know because I’m in process of repairing it now haha

When I read the title I thought they would be encased in epoxy or something like that.

Hot glue on your cells is not so serious.

The best way to fix your situation though would have to been to cut all the shrink wrap off and re-wrap them. Or if you really needed to keep the wrap cause you didn’t have extra, use a hot air gun to make the glue soft, then they come apart easy.

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You can try using a cotton swab with isopropyl alcohol and lightly dab over the glue and battery contact area. It will loosen up the hold considerably.

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This works too. :point_up: :+1:

The sides of the cells are negative, i see no short coming from a loose silicone spot. There’s nothing wrong in hot silicon. Just rewrap and move on.

You also fucked up with the positives and minuses. If you were planning on making 10s4p it wouldn’t work out. The pack would go - + + - + - - + etc. it needs to be - + - + - + etc.

This happened when I wanted to redo a cell that didn’t sit right, I put a new cell in there and saved the one with messed up heat shrink as one of my extras. After that once incident I made sure them cells glued in the right position lol

Also working with a large hot glue gun is dangerous, the glue will fall on your skin and get stuck to it so it continues to burn you as you fight to remove it and skin comes off with the glue… Becareful guys lol

The fact that the cells casing is live is what’s dangerous. If there’s a short between two different P groups’ negative casings, then you’ve dead shorted a cell.



I worked for a roofing company one summer where you’re dealing with 600 degree liquid tar. If you got some on your skin, and everyone did eventually, if you tried to remove it while it was still hot it takes the skin too. If you wait till it cools you can peel it off and you’re just left with a first degree burn. So you had to grit your teeth and take the pain for the minute or so it took to cool. Hot glues not that hot but works the same. Suck it up and let it cool and you can keep your skin. :grinning:

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