BLF Community Battery Pulls Overview Thread (Laptop packs and Tool Packs)

Took apart a Dell Inspiron battery pack - J1KND (11.1V; 4400mah; 48Wh). This one was a lot harder to open than my first HP battery pack.
LG LGDAS31865 2200mAH (10A ?) 3.7v cells inside.




Edit: all 6 cells measured ~3,9V. So not bad I guess.

Coming back to my previous pull. 3 cells measured 2V, other 3 - 2.65V. Some guys say that it’s only safe to charge cells that are at least 3V when pulled. How much truth is there? Still waiting for TP4056 charging board I’ve ordered earlier so wasn’t able to try myself. But maybe I shouldn’t if it’s unsafe?

It was like a no name laptop that I trashed. I just made sure that I got the pack model #.

eas has an extensive article on his site explaining how determining cell health from a voltage screening off the pull is can be moot. <2.7V is still caution territory I reckon, but with quality brands like the LGs you pulled may be able to get away with it. Cells manufactured in China like Lishen or EPT may not be so hopeful; just watch carefully for a few red flag observations like heat during charging.

Best way to assess cell health I suppose is to run them through an analyzing charger of some sort.

Thanks for the link, Otanacious.

My current POV is that, indeed, cell voltage from a laptop pull is of limited utility as a screening criteria. There are too many factors that go into it.

Below a certain threshold though, cells from laptop pulls should definitely be pitched. As to what that threshold is, I haven’t found a hard-and-fast-rule. I think ~2.8v is too high, and leads to a lot of perfectly good cells being pitched. I’ve decided to go with 2v as my cutoff and so far, so good.

BatteryU talks about cells becoming irreversibly and dangerously damaged if they stay below 1.5v for a week or more, so 2v leaves a big margin above that. Laptops will slow charge if some of the banks are below 2.8v. The low-voltage threshold given in battery datasheets is for cells being discharged under load, not for self-discharge of resting cells, it has safety margins built in for potential overshoot during discharge.

I’d be much more cautious with unprotected cells that have seen use in a flashlight or similar. In that case, I’d probably pitch them if the voltage was below 2.8v or so, since there is no way of knowing if the low voltage was due to overdischarge under load vs slow self-discharge.

Just cracked open my first laptop battery pack for my very first post. $12 free shipping on ebay. Condition: Used - “BATTERY WILL HAVE 1 OR MORE OF THE TOTAL 3 HOOKS, MISSING BROKEN”

Manufacturer Lenovo
Battery Part # Thinkpad 42T4801
Battery Pack mAh 10.8V 8.7Ah 94Wh - 9 cells
Cell Name LG LGABC11865
Cell mAh 2800

The battery pack itself was a pain in the butt to open up and on the bottom side was a good amount of amazingly hard glue holding them to the plastic case.

For now, some voltage readings:

1 2 3 4 5 6 7 8 9
3.997 3.976 3.987 3.987 3.989 3.986 3.986 3.996 3.997

Average: 3.989 Range: 0.021

I’ll run them through the analyzer and see what we get. I’ll be labeling, re-wrapping, and adding protection circuits to these if they test out good.


image links to album

thread updated thanks shhyguuy

I ripped apart a Compaq Evo N600 14.8V 4400mAh with 8 cells. They are Chinese 18650C4 cells .


OP updated thanks for the post.

Dell Rechargeable Li-ion Battery TYPE C1295
11.1V 53WH
6 cells
CGR18650D
Li-ion
MH12210

Was it a generic pack like the one in the amazon pic you used?

It looks generic like the picture, no branding. Has a made in China sticker on the side. Whoever owned the laptop must have bought a aftermarket pack.

I know, I know! Don’t trust eBay stuff. But, I thought it would be a decent deal, so I did it. I bought what was supposed to be a new, never used Toshiba PA3450U-1BRS laptop pack. It is a 4-cell pack, and the cells are Sanyo UR18650Y L43C, as Jubeldum found in another Toshiba pack a while back. They are 2000mAH cells.

Here’s the problem. I opened the pack and tested cell voltage and got 0.49v for all four cells in series! I thought maybe there was something going on with the balance charger circuit giving me a false reading, so I took it all apart and separated the cells. I got about 0.12v each or so. These are supposed to be brand new cells. Must’ve been REALLY OLD STOCK. |(

So, being the brave, daring (translation: stupid) person I am, I set out to charge them up, thinking that since they have never been used, maybe a jump-start will be all they need. Well, my Nitecore i4 charger just blinked at me, so I pulled them off, and tested about 0.26v on a couple of them. I figured that means the charger was bumping a little bit into them as a check for voltage/charge characteristics was taking place. I thought that looked promising, so I decided to go all out and be as stupid as I could be. I have an old phone charger wall wart that I cut the plug end off of a while back so I could use it as a power supply. It puts out 5.2v @ 1A. I held the loose wires to the positive and negative end of each cell for a little while (less than a minute each) and tested around 2.5v on each cell after that. Looking good! :wink:

So, I put them back in my Nitecore i4 charger and they sat there charging for a couple hours. They got just a little warm, and after pulling them off, they each measured around 3.5v or so. I only took them off because they are as-yet unproven as far as safety, and I didn’t want to chance something happening overnight. I’ll put them back on charge this afternoon and see if I can get them to a full charge. Meanwhile, I’m going to contact the seller on eBay and see how well his/her conscience works. I obviously have “voided” any regular warranty they might have had. But still, the cells were bad and something ought to be done to rectify the situation.

I can report that Milwaukee uses 10 Samsung 20R’s, at least in their 18v 4.0ah “RedLithium” packs.
…………………………
Are there any tool packs known to have 4.35v sells?

Be interesting to see if a cell that dead for that long has any probability of being useful at all….let alone safe. I doubt it IS dangerous, it’s probably too dead.

BTW, you know you can use low amp NiXX charging to bump a low cell up to charging range?

I think a lot of people are too conservative in their choice of cut-off voltage for scavenged cells, but trying to charge Li-ion cells that were well below 1.5v for months or years is, to me, sheer madness.

In general, I think NOS packs with anything less than ~2,400 mAh nominal cell capacity are probably too old to be worth the trouble, unless you find it in a recycling bin.

If people are looking for inexpensive packs on ebay, try this $12.95 pack. I haven’t ordered one, since I still have a huge number of NOS and used packs to go through, but it looks a lot like the (now unavailable) $12 NOS Acer packs that have yielded so many nice pink Samsung 2,600 mAh cells. I’ve used cells from those packs that were ~2v (most were higher) when I pulled them and they are doing great.

I need help identifying some laptop batteries.

#1—Lenovo Thinkpad-5.2 AH-10.8v
Battery #’s_LCQM2B8—with a “D” on battery body
Battery Wrap Color_Red with Lt. Blue Tip—(+)

#2—Dell—TK330—56WH—10.8v
Battery #’s_LLLM4C9—-with a “C” on battery body
Wrap Color_Red with Blue Tip—(+)

#3—I don’t remember which battery pack these are from.
Battery #’s__JIUFK17—-with a “D” on body
Wrap Color__Red with Green Tip—(+)

:star: EDIT :——I forgot to mention the Red wraps
are kinda transparent with the #’s printed on the
metal battery bodies. The #’s can be seen thru the
wraps , if this helps to ID them.

I have looked and I can’t find out any info on these
batteries. Can anybody ID these batts or point me
to the right places to look for the proper ID info ?
I also have more batteries , I need to find out the
ID info.

They all sound like Sanyos. I think the red wrap means 3.7v nominal, 4.2v charge termination.
Light blue is probably 2,600 mAh, green might be 2,400 mAh. I don’t know about the Blue, but given the rating from the pack, I’d guess 2,600 mAh too.

Is it just me or does it make sense to get a charger that can give you either iR (Internal resistance) or mR (mean resistance) reading right up front, so we can consider if we even want to put a specfic cell on a charge cycle?

I have had great luck with the LiitoKala Engineer Lii-260 and Lii-300.

for half of what a resistance tester costs I get a charger for free. and with no fan noise.

my $.02

Yeah, I’ve done that before. In fact, that’s what gave me the idea for using this wall-wart to do the same thing. My NimH charger didn’t have slots big enough to stick a 18650 into, so I had to cobble something together with wires and magnets to make it work. This, I just held in my hand, holding the bare leads to each end of the cell. If it hadn’t jumped up in voltage so quickly doing that, I wouldn’t have bothered with them any further. But, to go from 0.26v up to 2.5v in less than a minute made me think it might be worth trying to get a real charge into it, especially since they are supposed to be new, never used. I still have yet to get a full charge, though. I put them back into my charger last night for a few hours, but again had to pull them before finishing, because I’m not going to leave them charging overnight at this point. After last night’s charge, they measured around 4.0v each. I wish I had a hobby charger to test capacity and run-time.

All the 18650 cells I have are pulls from DEAD laptop batteries. The highest any of them tested when I pulled them was around 4.0v, IIRC. But, a lot of them tested below 3v, and some tested below one volt. I even had a really old pack in which none of the cells tested above 0.9v, and I was able to get a charge into most of them. Did I happen to mention I’m partially insane? When I was a kid, my favorite things to play with were the dangerous things. I liked fire, electricity, strong chemicals, and sharp knives. I’m only a little less crazy these days. J) But, let me reiterate that I thought these cells would be NEW and that’s the only reason I bought them. I can’t return them, because I tore the pack apart, so I’m trying to see if there is any hope for them.

I bought a ‘New’ generic laptop pack off eBay and it was completely dead. All 6 (unbranded) cells were reading 0.4v or less. Luckily the seller gave me a full refund without question. Just as well as I had already ripped the pack apart. :wink:
As I had nothing to lose I s l o w l y got them up to 3v using the NiMH setting on my hobby charger, then a normal LiPo charge at 0.5A. All 6 got to 4.2V without getting even warm and all have been working fine in low-amp lights ever since. Capacity is about 60-70% what it should be but as they were free and I have 6 to play with, I’m happy.