Rewrapping a battery

HKJ

Flashaholic
Joined
Mar 26, 2008
Messages
9,704
Location
Copenhagen, Denmark
[size=+3]Rewrapping a battery[/size]

DSC_1789.jpg


The above battery cannot be used anymore, it will short and might explode.
The wrapping will sometimes break, luckily it is a fairly simple operation to fix it.



[size=+2]Tools and parts needed[/size]

DSC_1801.jpg


I am using shrink wrap to repair the battery, due to the heat gun I uses, I have selected a low temperature type.
When flat it is 29.5 mm wide, the inner diameter is 18.5 mm, it will shrink at 80 Deg. C.
I bought a roll with 25 feet (7.6 meter) on ebay for $11 (Sellers name is atop_authentic_auction). This roll will last for more than 80 batteries. Fasttech has heat shrink in 1 meter pieces for less than $1.
This heatshrink is also fairly thin, this is an advantage for some lights.
Often heat shrink is specified in width of the flat tube, the table below shows the minimum sizes for different battery sizes.
diameter.png


DSC_1802.jpg


As a heat gun I uses a hair dryer, it is not the perfect tool for the job, but it can be used.

DSC_1803.jpg


I do also need something to measure with, my digital caliper is fine for that (A ordinary ruler could also be used).
With a caliper, remember to cover the jaws or it will short the battery.

DSC_1804.jpg


To cut the heat shrink I uses scissors.



[size=+2]Rewrapping[/size]

DSC_1790.jpg


I want the heat shrink tube to be about 3 mm longer than the battery at both ends, with a 68 mm battery this means 74 mm tube.

DSC_1792.jpg


The new tube for the battery has been cut of the roll.

Unwrapping.jpg


I uses the fingers to removing the old heat shrink, using a knife or scissors is unsafe.
If there is two layers of heat shrink, only remove the outer layer.

DSC_1791.jpg


The "naked" battery, do not try to bend the protection pcb out to get a look.

DSC_1794.jpg


Putting the new heat shrink onto the battery.

DSC_1795.jpg


There will be about 3 mm extra at each end.

Shrinking.jpg
Shrinking2.png


Applying heat, rotate the battery and swipe the heat gun back and forth. If using a real heat gun, be careful with the fingers holding the battery!
It is possible to increase the temperature by covering part of the air intake on the heat gun (This might also melt the gun if overdone).
The battery must not be heated much (As long as it is possible to hold it, the temperature is fine). This is usual not a problem, the heat shrink will shrink long time before the battery is heated.



[size=+2]Final result[/size]

DSC_1798.jpg
DSC_1797.jpg


DSC_1799.jpg


DSC_1800.jpg


With a new covering, the capacity information is gone, to fix that I have added a label with capacity. I also included the date I got the battery.
 
Last edited:

Dubois

Enlightened
Joined
Feb 12, 2012
Messages
660
Brilliant! I just bought some battery shrink wrap from Fasttech, just in case. Now I know how to use it should the need arrive. Thank you HKJ.
 

jaycyu

Enlightened
Joined
Jun 29, 2012
Messages
413
Location
Vancouver BC Canada
_MG_3443_zps2ff3ff5c.jpg

Success!
Thanks for the picture tutorial, HKJ.
I bought the shrink wrap from FastTech's site, though they didn't have caution-yellow that fits 18650's.
 

RWeis

Newly Enlightened
Joined
Mar 13, 2013
Messages
23
I rewarpped a couple of 18650 as per your directions and it was extremely simple and very effective.

Get the material, used a heat gun on low, cut the correct length, get old wrap off, slide new wrap on, center the physical battery, slowly heat shrink wrap, done.

Thanks

Bob Weis
 

Derek Dean

Flashlight Enthusiast
Joined
Nov 14, 2006
Messages
2,399
Location
Monterey, CA
HKJ, thanks for putting together this little tutorial. I've got an 18650 cell that really needs to be re-wrapped, and with your thoughtful directions it now looks easily doable.
 

HotWire

Flashlight Enthusiast
Joined
Mar 9, 2011
Messages
1,651
Nice tutorial! I've used Fasttech's 18650 shrink wrap and it's ***perfect*** (and inexpensive). Some automotive shrink wrap is too thick.
 

walterwitt

Newly Enlightened
Joined
Feb 23, 2013
Messages
27
Just rewrapped my first cell from an old laptop battery. Got some black heatshrink from Fasttech and it arrived this morning. a few wrinkles and it's a tiny bit off center, but it's a lot better then the electrical tape I had on it before.
2Wq1BTH.jpg


2Wq1BTH.jpg


siEmaxS.jpg


TtA1GuN.jpg


Thanks HKJ.
 

mhanlen

Enlightened
Joined
Jul 14, 2013
Messages
494
Location
Eastern USA
This is a great tutorial. I know for some this stuff seems obvious, but these sorts of step by step tutorials really help a lot of people (and potentially) and help to curb questions.
 

tatasal

Flashlight Enthusiast
Joined
Jan 25, 2012
Messages
1,192
So far I have not seen any vendor selling the thicker, clear plastic wrappers used in most protected cells. Any information would be greatly appreciated.
 

HKJ

Flashaholic
Joined
Mar 26, 2008
Messages
9,704
Location
Copenhagen, Denmark
So far I have not seen any vendor selling the thicker, clear plastic wrappers used in most protected cells. Any information would be greatly appreciated.

You can find clear shrink wrap on ebay, but I do not know the thickness of it.
Generally you want a fairly thin shrink wrap or you might have problem with fitting the battery in some lights.
 

kosPap

Flashlight Enthusiast
Joined
Mar 1, 2007
Messages
2,894
Location
Naoussa Greece
indeed...the clear wrappers are thicker. I think they are also available from fasttech

Just rewrapped my first cell from an old laptop battery. Got some black heatshrink from Fasttech and it arrived this morning. a few wrinkles and it's a tiny bit off center, but it's a lot better then the electrical tape I had on it before..

what method of heating did you use? I think yuo can work on it a bit more with a hairdryer. the off center is iether because of too uneven heat or not-squared cutting of the wrap
 

LuxLuthor

Flashaholic
Joined
Nov 5, 2005
Messages
10,409
Location
CT
It's too bad you can't find the typical 1 or 2 mil thick shrink that original cells are wrapped with. Most of the typical wrap sold is 5 mil (=0.005 inch)
 

tatasal

Flashlight Enthusiast
Joined
Jan 25, 2012
Messages
1,192
Received from FastTech the 18650 transparent and black shrink wraps. While the transparent are great, the black ones are crap, poor quality. First of all, they are a little loose when fitted, and when heated, it does not shrink cleanly like the blue, yellow (aa) and the transparent ones. Avoid their current black 18650 wraps.

Btw, how do you eliminate the crease on both sides of the wrap to make it look just like from the factory?
 

kosPap

Flashlight Enthusiast
Joined
Mar 1, 2007
Messages
2,894
Location
Naoussa Greece
How did you heat it? It makes a difference if you used a good hair dryer or a lighter

I make the main shrinking with the dryer and then work the creases with a BIC lighter. fast and not very close, if you overdo it the transparent wrap will tear on the crease.
 
Top