# Heatshrink sizing [SRO]

There is confusion about the best heatshrink sizes to use for making batteries.

So I want to ask all of you – what size heatshrink do you use?

single row of 18650?

two wide 18650?

two wide, two tall 18650?

two wide, two tall, offset 18650?

single row of 21700?

two wide 21700?

two wide, two tall 21700?

two wide, two tall, offset 21700?

Any other geometry or sizes?

26650?

What size do you use?

heatshrink size heat shrink battery cells 18650 heatshrink 21700

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lol

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220mm (flat width) is too big, don’t try it.

What size I should get for 21700 pack? single stack stacked length side.

Height + width + wiggle room = desired flat width of shrink

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You can use the following to get the height of staggered packs

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Lol, I just draw them and measure the drawing

#fuckmaths

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Close enough for government work

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Pretty much this is what I do. Flat diameter is what you’re after.

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SOOO MANY SIZES

At least I want to get a confirmation on the size needed for the 12S4P PCB kits from @DRI

12S8P 18650 I got 230mm following the steps above.

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I think the 1.2 multiplication factor could be a bit less.

I measured the extra material and there is about 30mm max so I think I could take about 20mm less.

So next time I will probably order 210mm

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That’s going to be very difficult to shrink without getting creases.

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Good thing I’ll be selling it then

Jk but it isn’t a paid job it’s for a friend. So he can come over and fuck it up himself.

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If you have extra heatshrink, just do it once, get all the creases and stuff in it, learn how to avoid it, then cut it off and put another piece on

Don’t short out the cells with your scissors either.

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here’s how i do it.

• measure the width
• measure the height
• add the width and height together to get a no margin flat width
• add 20mm to get a margin
• buy whatever you can find that is closest to that flat width that won’t take 6 weeks to get here
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This is the part I struggle with. Mine are always found on AliExpress

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