Rewrapping a battery

Wurkkos

Richwouldnt

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Apr 17, 2011
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Reno, NV
I used precut lengths of wrap from Illumination Supply (illumn dot com) and hit one difficulty. The groove behind the head of the unprotected pack pull batteries I was rewrapping is deep enough so if the shrink wrap is heated too much it shrinks excessively and splits when it shrinks into the groove. Very little shrinking is required which means minimal heat and taking care.
 

Ana

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Dec 1, 2014
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Hi All readers

Great shown with pictures and text, but this material called Layflat heat shrink (if looking for some) is best heated from the middle outwards, so it grips the middle to avoid cold spots appearing to make it unsightly. Make sure you get the right Layflat wall thickness as these PVC heat shrinks start from 0.07mm up to 0.20mm, a general standard is 0.15mm which will accomodate the heat the batteries will give off.

cheers

Ana
 

LetThereBeLite

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Oct 27, 2010
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Just stumbled upon this very helpful post.

I dropped a 14500 battery from waist high a month ago and the tight manufacturer black wrapping split/tore at the positive terminal side of the battery. :(

It was a little annoying as I had just purchased this high quality Panasonic cell. I used a little bit of electrical tape but it's not working that well. Will give this fix a try.

Thanks for posting this HKJ. :twothumbs Very helpful!
 

Arizona_Mike

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May 4, 2015
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Thanks for this great post. I've used a lot of shrinkwrap over the years but did not know about the low temp stuff and knowing the needed size and excess length saves a lot of experimentation and money.

I actually have quire a bit of re-wrapping to do. I found a great deal on non-Chinese protected UN 83.3 2600mAh 18650 cells but they are almost 73mm long and fit . . . absolutely nothing! I have had to de-button them to make them usable and I have a little bit of thin vinyl cleanroom tape keeping the original shrink wrap form opening up more where I make the small incision.


Mike
 
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202BIGMIKE

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Apr 16, 2014
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In case of some tears and nicks in battery wraps and you are where you don't have access to wraps and a heat gun to shrink

the battery wrap replacements , you can use Kapton tape. (Google: kapton tape) They make lots of different tapes for electrical

items. Check them out , see if they have something that fits your quick repair needs. I hope this helps someone in need.
 

Rick NJ

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Feb 8, 2013
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I redid most of my 18650's lately. I used to use regular heat shrink tubing, but with the re-do, I switched over to fasttech's pre-cut transparent wrapper for my 18650's. It works out much better for me then the thick heat shrink tubing.

The FastTech pre-cut are 72mm long and works very nicely when without a protection board. With the transparent wrap, I wrap it over the original battery wrap and I know I got good coverage and yet see the original battery markings/labels. I add my label (battery ID, date I salvaged it, and where from) under the transparent wrap. With the original wrap under the transparent new wrap, any scraps/wrinkles made during battery extraction causes the new wrapping to have a bump. This increases the battery diameter just a bit. It works very well.

72mm is a bit short when a protection board is added. If the wrapper is 74mm or even 75mm, they would be perfect. The protection board adds 1.5mm. The top-cover also adds another 0.5mm or so even while it is not a button top with a protruding nipple. Room to sneak the wire in (to connect to the protection board), insulation...

[topCover 0.5mm] & [insulation and wire to protection board 0.8mm to 1mm] & [battery 65mm] & [insulation+tape 0.5mm to 1mm] & [protection board 1.5mm]
Total= 68.3mm to 69mm

With redoing the wrapping this time, I am more experienced than the first time and I generally get it down to just around 70mm long. So, 72mm wrapper is too short to grip both ends well. I usually let the top loosely grip (saving more length for the bottom) and add another layer - this time grip bottom poorly saving more length on top to grip the top well. The two layers grip both bottom and top well and (double) protects the bare-wire (that goes from + to protection board) from external scrapping. This triple layer (original+two new layer) battery is not just long, it is also a bit on the fat side. The round wire from + to protection board adds 0.5mm to the diameter plus 0.1-0.2mm insulation paper under it. So my protected batteries (newly rewrap ones) are 69-70mm long, and 18.7-19.2mm diameter.

EDIT: updated - with more suitable material to make it shorter and thinner diameter 18.54-18.57mm and 69.25-69.70mm long

For the protected batteries, I decided to redo it one more time since the thick diameter is not fitting into my (new) second 18650 flashlight:
- use fasttech's NON-pre-cut transparent wrapper
- use copper foil instead of wires to connect B+ to protection board

The fasttech's NON-pre-cut transparent works well (cut to 75mm+-1mm) so one layer will do. With the copper foil (5mm wide 0.03mm thick) plus kapton tape under and over (total 0.15mm max). The copper foil is very difficult to handle but far superior to wire. It is not as thick as 26AWG wire even with kapton tape under and over it. I cut down on the diameter by at least 0.5mm.

With twelve 18650 redone, all diameter range 18.54-18.57mm and 69.25-69.70mm long. Now all twelve fits into my flashlights.
 
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Nazo

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Oct 27, 2015
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I'd been wondering about heatshrink wrap. One thing I've been wondering about though: heatshrink wrap basically appears to be a type of rubber and some is quite thick. Companies generally wrap their batteries with some sort of plastic that seems to at the very minimum be less thick. But I've been wondering: is there anything maybe we could be using that is better than heatshrink wrap for the battery? Specifically, I'm wondering about all the heat that can be generated in some applications (such as many high powered flashlights that can use 2+ amps from the battery) where the battery can get quite warm. Obviously it's not in any sort of danger zone in any reasonable application, but I worry about really long term wear and tear on the batteries due to the extra wear from the heat. (This is partially just a sort of OCD thing for me really. Like I said, I realize they are nowhere near exploding or anything, but they do get fairly warm at least.) Specifically I'm wondering if there might be something that's at least somewhat thermally conductive or at least less resistant than these materials.
 

markr6

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Jul 16, 2012
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9,262
cracking post, I tend to doubt wrap mine, for a snug fit/no rattle

Exactly!

I received 20 precut clear sleeves from Illumn last night. I used them to wrap some bare NCR18650GA cells since they're way too loose in most lights and rattle. It drives me nuts. I usually buy button tops to solve this AND to work with lights that require them, but I got a deal on these without button tops. So I just slipped the sleeve on, trimmed a few mm off, and hit it with the hair dryer. Perfect results!

They fit my H600w, just barely, whereas the mtn electronics button tops do not. I'm guessing it's a slight difference in wrapper thickness.
 

Niconical

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May 21, 2008
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Spain
Firstly, thank you to HKJ for this, and for all the other amazing and helpful tests, reviews and advice he gives.

I just thought I'd post to say that if you're undecided about rewrapping, it was a lot easier than I expected. I just did 14x 18650 (Eagletac protected and Panasonic NCR-B unprotected) with no problem. I used a hairdryer with directional nozzle thingy, and it was fast and simple.

I use the Panasonics in various power banks, and constantly removing and swapping them meant each cell had more electrical tape than wrapper. Although they haven't been used that much (maybe 50 cycles each) I was going to dispose of them. Now though for a few $$ I have 10 Panasonics ready to go.

The Eagletac 3400's (green/white) were pretty much cracking and peeling from day 1, so it's great to have them as-new, or actually better than new. Good batts, bad wrapping.

The only downside is that I discovered this thread AFTER ordering and receiving 8x LG MJ1s as replacements, but I'm sure I'll find a use for them..... :)

For the record I bought from the same seller as HKJ, atop_authentic_auctions, a strip that I cut to size myself.
 

nitebrite

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Jan 3, 2004
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Thank you hkj! i did not heed your warning even though i have seen this. just a little rip and a 18650 vented. let me tell you, it sucked! very lucky i was not hurt. there was a guy here that was very seriously harmed. since batteries are expensive and they tend to rip there is no reason not to wrap them. i even have the tubing,heat gun, everything on hand but no i did not listen to you. count myself lucky right now
plus in the other thread we see 18650 is harder to get now. so this is very good info.
 

JamisonM

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Apr 26, 2006
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South Carolina
I'm sorry to revive an old thread, but I'm curious how well the PVC heat shrink used for wrapping 18650 cells will shrink onto a AA battery? The only appropriately sized heat shrink for AA cells I can find is from Amazon. I can get quite a bit more if I get this 18650 heat shrink on Amazon and for not much more.
 

Arizona_Mike

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May 4, 2015
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I got great results with this guide a couple years ago but my cells are a little too thick for some applications. Where are you guys buying your thin/hard heat shrink. I've only found the thick somewhat rubbery stuff which is intended to flex with bundling wire. I have more to re-wrap and I'll probably redo the ones I did before so they fit more applications.

Mike
 
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