Shrink wrapping salvaged batteries

Batteries and Chargers Rechargeable Batteries
8

nice job on the re-wraps, they look very professional. I’ve used PCBs from DX in several builds, although off the top of my head none of them have drawn more than 1A. I have one coming for a pack to drive a friend’s XM-L@3A light that I made for him, we’ll see how that works.

TBH, I’ve never tripped one, so I couldn’t honestly tell you even if they work or not, so take the recommendation with a pinch of salt. I’ll be checking the short circuit protection on the one coming and I’ll have to get my friend to check the over discharge protection, although PCBs tend to trip way lower than I’m comfortable with (2.5 to 2.75V I think).

To add one to a cell, just tin the ends with solder. Tin the end of the short strip with solder and solder it to the cell so that the PCB folds back to show the plain bottom. Put a piece of electricians tape over the bottom of the cell and tape the PCB temporarily in place. Tape the long strip to the side of the cell to measure how long it needs to be. Cut, tin, solder. Remove temporary tape and do your wrapping magic. You’ll probably have to apply some pressure to the PCB while doing so, to make sure you don’t leave any compressible space between it and the cell.

9

Nice work! Thanks for doing the measuring for me; I already had a roll of the FastTech Shrink Wrap ordered to do just this. I have several laptop-salvage cells that had the wrap nicked, and I've had to repair those with kapton tape in the past.

@ Mattthemuppet:

I've tried ordering the protection circuits from DX recently and they were unable to ship them; after waiting a very long time, I finally cancelled the order. If you've had success ordering them recently, let me know so I can order some for my cells...

10

last one I ordered was 5 days ago and it says “full shipment”, whatever that means in DX speak. I’ll have to check again in a week. Last one before that was a few months ago, I think.

11

Looks like you have the shrink tube down. I have been using the stuff from an ebay seller. Don’t know how it compares with the fasttech shrink tube. The ebay stuff is clear so you can see the original manufacturer label after you’re done.

After wrestling with goo-covered pack pulls for quite some time, I stumbled across two aids in removing just about any gooey glue used. Sometimes if it is a light sticky tacky glue, I’ll use isopropyl alcohol. That seems to clean most of it off although it may lighten the manufacturer specks printed on the original battery label.

But the REAL trick for getting all kinds of messy hardened glue off the batteries? (especially the caulk-like white stuff.) A small piece of wood with reasonably sharp edges.

I use a SQUARE chopstick with sharp wood corners. I have NO idea how this works and stumbled on it in a fit of anger: “How do I get this *&^%$# stuff off!”

Rub the glue vigorously with the edge of the chop stick and it curls or just falls off. You’re not scraping it off really. You’re just rubbing it HARD with the wood edge.

How does it work? Breaking the surface tension? Cracking the glue? Got me. But it works. I know it sounds crazy. And it doesn’t hurt the most fragile original battery wrappers. Yes, it does take a little work, but nowhere near as much as you would think. I have used this trick on probably 50-75 pack pulls at this point and it works great!

12

I had the most trouble with the hard black RTV-type of adhesive used on some of the older Dell packs I've taken apart. I ended up having to carefully shave the glue from the pack with an exacto knife. Difficult to do without nicking the original shrink wrap...

13

>>>>>hard black RTV-type of adhesive used on some of the older Dell packs I

Try a sharpish square corner on a small piece of wood. Takes that black stuff right off. Or it has for me. Once again, you’re not scraping with the wood. Just rubbing, pretty hard. It curls up in little flakes and falls off. I know it sounds like witchcraft, but it works.

Don’t expect it to just fall off in a sheet after you touch it with the wood edge. You DO have to rub it fairly hard.

Good luck!

14

The packs I’ve opened normally have a form of the sticky stuff or the black stuff. Just rubbing with my thumb has worked on almost all of them. The Dyson pack had something clear like an epoxy that dried very hard.

Thanks for the tip, I’ll give that a try on the two packs I’ll be working on next - a Dell with LGs (probably the sticky stuff) and a Compaq.

On the protection circuits, I’d really like one that cuts off at ~2.9 - 3.0v, or so. Would prefer not to go with 2.5v.

Oh, the Fasttech PVC is not solid, but it’s closer to solid than clear. I can read through it. It’s pretty similar to the blue LGs pulls.

15

>>>>> Just rubbing with my thumb has worked on almost all of them.

Yeah, that’s EXACTLY what made me try the piece of wood. My thumb didn’t have any skin left on it after getting the gummy goo off 30 of those suckers.

>>>>>Oh, the Fasttech PVC is not solid, but it’s closer to solid than clear.

This stuff is perfectly clear. Not fasttech speed in getting here from china but not too bad. Very thin but strong. Gone through three rolls already. Takes VERY little heat to shrink it, much less than shrink tube for wire insulation. Hairdryer would be fine. Might be too sensitive for an open flame. Looks PRO when done, like it was done in a factory, almost like there’s no extra layer there at all.

I sometimes make TINY TINY nicks in the manufacturer’s shrink wrap when wrestling cells outta packs, so I always shrink tube the pulls. But as someone pointed out, sometimes you can’t save the manufacturer’s shrink wrap. It gets too beat up in extraction. Then I just cover the silver cell.

Oh, btw, i put the pull info on the cell with a sharpie UNDER the clear stuff, so it’ll never rub off, like: HD, 1-2-13, 3.85 v. For Home Depot, found 1-2-13, 3.85 volts when pulled. Then i use a sharpie on the outside to write down charge dates and charge voltage. I let em sit for a while after 3-6 charges and see how well they held the charge. I’ve found that it can take 10-15 cycles before the cell stabilizes and really starts to hold a solid 4.2 volts. So few of the cells I find are truly bad, i wonder why people throw ’em out.

The panasonics and the pink samsungs and sometimes the green sonys are great. LG tans, gray and turquoise samsungs can be iffy, but the tan LGs can rival panasonics if you get a good batch. I rarely find the red sanyos people say they always find. I’ve had panasonic pack pulls hold 4.2 volts for MONTHS, which is better than some new panasonics I have bought from various online sources, so I wonder how “real” the real online panasonics really are.

I LOVE pack pulls. It’s like opening xmas gifts! Never know what you’ll get.

16

TBH you’ll have a hard time finding a PCB that cuts off that high, even the high quality ones in AW cells and the like cut at 2.75V. At the end of the day it’s just added insurance to prevent you completely trashing a cell as you should be able to tell when a cell is nearly completely discharged, at least in linear drivers. It’ll be a bit harder in multi series setups with buck drivers, although ideally those should have some kind of low voltage warning built into the drivers.

17

Requested better than the DX version at Fasttech. I could live with 2.75v as it’s not that far from ~2.9v. Don’t plan on running pulls in a multi-cell light, though I suppose I might try some good Sony IMRs once I’m set up to balance charge.

I’ve only ever tripped on the low side once as an accident, but that is what protection is for. Normally I won’t run lights till the battery dims or dies.

I’ve had an XML in a P60 light refuse to run high on a UF3000 for more than a minute, but that seems to be the driver and not the battery protection circuit. After several recharge cycles, the UF3000 does run the led on high in a different host - though at relatively low current compared to a KP3100.

18

>>>>>Normally I won’t run lights till the battery dims or dies.

Most lights on unprotected batteries are pretty darn dim (borderline unusable) by the time the battery hits 3 volts. Many of my lights lose high by that voltage or start blinking.

19

Thanks, for this thread.
I have the shrink on its way too. I have no naked Batteries, but sometimes I rip the wrap apart to see what’s underneath.

20

Yeah, I’m frequently recharging around 3.2v - 3.5v now that I have so many spares it’s just too easy to pop in a fresh cell and the attended recharges don’t take as long. I’ve done a few around 3.1v but that’s fairly rare - mostly with the LGs.

The only light I’ve run dead off alkalines is a SK68 clone on NiMHs. It dims somewhat and then dies. Lot shorter run time than I expected, but it’s pushing a bunch of current. I haven’t run my 3 mode version dead yet, so no idea of how long I’ll get with it on low.

Couple more salvaging first for me in this thread.

21

Glad it helps encourage others. I’ve been tempted but so far the only ones I truly want to rip apart are my UF3000s. Just not like that guy using the hacksaw in the video.

22

>>>>>Just not like that guy using the hacksaw in the video.

I use a dremel cutting disk to do one long side of the pack, being VERY careful not to hit the batteries, but you’re going in with the dremel at the BOTTOM of the cell, so that bottom edge of the cell is pretty recessed and hard to hit. It’s in like a half inch. Haven’t even nicked one yet.

You can do it without that initial cut, but it gets old fast. Too much work. then I grasp the cut edge of the pack with a ROBUST pair of needle noses and twist clockwise as I pull up on the pack. That’s usually enough to pop the whole plastic piece loose, or enough to get the batteries out with a minimum of fussing.

Just cut ’em out +FAST+ because a short can heat those things up hotter than a stove top in like 3 seconds. I have accidenetally shorted an 18650 outside a pack but no shorts while doing a pack yet, but it is a bit of a pucker time for me. I don’t really like that initial quick cutting of leads to prevent shorts. Kinda hairy. So many wires going every whichway. No telling what will short and what won’t.

You have to be careful too. the batteries dent easily and I wouldn’t use a dented one. They’re not like an alkaline battery just stuffed with some compound. There’s a thin plastic bag in there filled with the catalyst, rolled up like a jelly roll. But it’s not completely liquid. There can be crystals in the catalyst, and if one of those crystals rips the thin bag, you could end up with the famous “venting with flames” somewhere down the line. Manufacturers of li-ion battries say to chuck a cell even if you have just dropped it hard, because of the possibiity of the jelly-roll bag ripping.

I dremel off the solder bits after pulling off the tabs, being way careful not to cut too far into the battery case, another no-no. Then shrink wrap and I’m done. Oh obviously I test the cells when I get them out of the case for their voltage before going any farther, but 90% of the pulls I find are fine.

23

Quote Gottazoom:

Process:

- Cut wrap to 70 mm lengths ($0.06 each @14 lengths + small scrap from a meter) using a Fiskars cutting board my wife keeps for hobby use

- Placed battery so that top would insulate and not cover the + pole

- Used hair dryer/blower to start shrinking at the top where it folds over

- PUSHED BATTERY OUT OF TUBE, ADDED (SALVAGED) INSULATOR, PUT BACK IN TUBE

- Finished top of battery, moved to bottom, finished body last

- Easy to fix your own [or make fakes ]

Refer to the step above in ALL CAPS:

I’ve never done this so I must ask: Why must you push battery out of tube and then add insulator? Seems like an extra step when you could start with the insulator in position then heat and fold…What am I missing?

24

Bump

25

Sorry I missed this earlier.

My first tries I started with it in place but the dryer’s air flow kept knocking the insulator out of place and sending it across the room. Which led to some less-than-fun hunting.

The extra step literally saved steps and time for me. One might use a little adhesive; I just wanted to make sure I didn’t even partially close vent holes and it really was easy to do it the way I did. I’m sure somebody will come up with a better way and post here for us.

26

” I let em sit for a while after 3-6 charges and see how well they held the charge. I’ve found that it can take 10-15 cycles before the cell stabilizes and really starts to hold a solid 4.2 volts. So few of the cells I find are truly bad, i wonder why people throw ’em out.”

I have found this as well. I had my old Toshiba laptop that I pulled the cells from. After two cycles, two of the cells would only charge up to 4.06v. I marked that on the wrapper but continued to use and charge them because at the time I was short on 18650s.

After 10-12 cycles, those 4.06 marked cells now hold 4.18 like all my good ones. I can not tell any difference in them now that they have stabilized.

Many cells can be saved. If they are at 0v I don’t bother. If they get hot while charging, I stop and trash them. If they take forever to charge, I trash them. Beyond that, many can be saved if you want to.

27

So I have got my shrink wrap last week and used it today.
The shrink wrap was tighter than I thought, but it worked flawlessly.
On the TF battery the top insulator ring is glued on so it was really easy.
I posted the pictures in another thread.