Video tear down of a laptop battery pack

I made a video of how I opened my first ebay battery pack.

I have never tried before, so it's a novice's approach.

Here's a search link from ebay for it.

The cells inside are Samsung ICR 18650 26C. There were 6 cells in the pack.

The voltage averaged 2.0 volt, the high was 2.56 and the low was 1.98

I am not 100% sold that the actual cells are Samsung. There are numbers on the cells, beneath the wrap and they are all different numbers, so I do not trust the quality or age of this thing.

The pack was new, but most likely Old Stock.

The video just shows how I got them out and prepped them.

Once they are charged, if they appear to work as new, I will sell them. I don't have any need for them. I just wanted to tear down a pack.

EDIT: I do not condone buying laptop packs to get batteries. I think paying the bucks for the premium batteries, from a reliable dealer, is the right and safest way to go.

Great teardown OL. No gloves and no cuts, great job for the first teardown. I can’t wait to see the voltage on the after all charged and tested.
I am going to try to work on a laptop batter tear down and yield chart soon.

Well I ordered a couple of packs, I like these samsung cells, thanks for the video. I like to leave the welded tabs on and cut close to the middle and burnish the cut edge with a socket extension or the like, as I’m chicken I’m going to tear a hole in the end of the cell. Hope they take a charge :slight_smile:

I figured I would give an update of the charging status. I put four in at 2pm. It's now 1am and two have "charged", the other two are not. The two that show charged read 4.2v and 4.1v. Now, I have to stop and qualify what I normally see. I have a bunch of Efest batteries, from 10440 to 18350 and I have some 20R 18650 and some Panasonic 10 amp 18650 cells, plus the Sony 26650 cells. ALL of them charge to 4.2v - 4.22v. ALL of them. I never have one charge below 4.2v. I never have any take 12 hours to charge and I have had a couple occurrences where cells ran down to about 2.4v. (I take that back. The Sony 26650 cells take a long time to charge).

The other two of the four I put in now read 3.8v. So these cells are taking a long time to charge. OK, I know they were low, so it takes time, but...

I took the cell that was charged at 4.2v and hooked it up to my "test center", which is an XM-L on a 20mm star, on a 1-1/2 diameter piece of aluminum rod stock, that is 18" long. That way the star never gets hot. I just use two 18ga leads and DD from the battery to the led. That usually gives about Edit 4 amps drain. Well, the test cell dropped to 3.7 volts immediately and dropped to 3.4 volts after 1 minute. Then it dropped to 3.2 volts after 4 minutes and leveled out. I thought that was ok, but after 10 minutes it got hot. Hot enough that I didn't want to touch it.

That tells me this is a cell with very high resistance. I have done this test with my 20R and Panny cells, as well as Efest cells and the only other time cells get that hot, is when I test out 10440 or 14500 cells, because they can't take the 3 amp discharge and they are worked too hard.

I'm not impressed as of now. I will continue to charge all six of them and then I will test them, but right now, I believe they are high resistance and I would not be interested in them, no matter the cost, unless it was in a low drain light, 1.5 amps or less.

That's how I feel about it, but draw your own conclusions, because I am NO expert at this at all. It's just what I see and what I think. Just my personal biased opinion.

Some of those cells may be in better condition than you think, which isn't to say that they're good. You got it right. They look to be a good match for low current lights as even the AW version HKJ tested had 4x the IR than -20R's.

2V is too low for a lithium cell. The cells are probably damaged. (lower capacity, higher IR)

None of my cells were that low voltage and they all charged normally to 4.2v. I will run a 1A discharge test on a few today.

I'd charge and discharge at 1.3A so you can compare to the data sheet. If you discharge to 2.75V, the capacity should be 2340 mAh.

These packs are not new, but rather pulled from working laptops.

My best pulls were from a few Toshiba toughbooks. They yielded panic ncr’s @ 2900mah. Being 4 yrs old and didn’t faze them at all.

When you buy a new laptop, the battery pack is packaged separately and has never been charged. It is sitting at the ideal storage voltage. A laptop pull is different. If it has already been charged, and even never used, is not going to do as well as time passes. In buying laptop packs, look for OEM, NOS. Here is the link to what might have been the all time best deal on eBay.

Well, I did some more testing this morning and with my Panasonic "CG" 18650s, I get about 4.4 amps drain DD to the led. All 4 of my Pannys read just about the same, within a tenth of an amp.

With the two charged Samsung cells, I get 4.2 amps from one and only 3.5 amps from the other and the one with the lower amps definitely gets much hotter.

It's enough for me. I will dispose of these cells. They are bad and I believe,they were drawn down too low and are no good to use. Iffy at best and I just don't want to mess with them.

I will stick to paying the big pucks for premium cells from now on. Never again from Ebay.

Discharged 4 cells at 1A via Opus… Minimum was 2510mah and maximum was 2656mah from ~4.2v to ~3.05v.

These batteries are listed as “New OEM”

I would too, I get all my laptop batteries for free, so my reclaims are free.

They may not be much good for high-drain but perhaps would be OK for use in a USB power bank. Those things run parallel cell arrangements and often output no more than 2A via the USB port.

Your call OL on whether it's worth the messing about but some members seem to have been luckier with laptop packs. For high-grade lights the Pannys are worth the money IMO but to charge a cell phone with a ML-102 for instance, you (or another member) might get some life out of these.

Does seem strange that they would take so long to charge though.....

Well it reads “pulled from new laptops” So…

One would think they were new, but they don't seem to be.

I personally don’t believe the “pulled from new laptops” part.

How do you sell these “new” laptops that are now missing batteries? When a new laptop doesn’t sell they mark down the price until it moves. Even when you use a laptop in place of a desktop no one pulls out all the batteries and sticks them in a closet until they are only worth $10.

Do these things say Acer on them?

Mine looked brand new when I got it - no nicks, oil spots, scratches whatsoever.

They were “sleeping” cells…you don’t hop out of bed raring to go anymore…takes a little bit to get back up to speed

Charge/discharge them 2-3 times, that will re-awaken the cells

Sometimes one or two of the cells in a battery can go bad when they sit for long periods, this is one of the main reasons that laptop batteries (and those Li Ion cordless drill/saw packs) will no longer charge/hold a charge

Excellent video by the way!


My only charger is an I4 charger. My only means of discharge is an LED. I do not plan on buying any more equipment for laptop packs. For the cost of a hobby charger/discharger and all the extras, I can buy another couple sets of good new cells, so it's not worth it to me. I was really shooting for doing a pack just to see what they were like and that's what I did.

Not worth my effort for sure, but to each his own. I know many like to do it and that's great, just not for me. I just finished up with discharge and recharge and another discharge test. I find two out of six would be what I feel are acceptable and two that are marginal, along with two that I feel would be dangerous to use.

All six will be properly disposed of.

It was a learning experience. I see that I would need special equipment, to do it right and I cannot spend that kind of money, but it was good to learn what I did.