Tutorial: Laptop Battery Pack 18650 Extraction

[lemlux]

After I twist off the main part of the negative end tab with needle nose pliers I deal with the the four sharp tig-weld prongs by gently tapping the battery on a tempered glass surface. The result is an uneven but not sharp surface.

As for the tabs on top, I usually leave enough material so that I can double, triple or quadruple fold the tab remnant to make a quasi button. I then tap this end on tempered glass as well until the surface is relatively smooth to the touch. Accordingly, on most lights except those with the smallest diameter recesses for anode contact I can avoid having to use a small magnet to make contact.

 

[LuxLuthor]

I've never bothered to remove the welded on tabs when I salvage cells. I just trim the tabs down with a diagonal cutter and smooth the edges so that I don't cut myself on them later.

Besides aesthetics, is there a reason to actually remove the tin(?) tabs welded to the cells in a laptop pack?

--flatline

Yes. To make sure you have even contact surfaces in applications, and for when I re-spot weld battery tabs & balance leads, I need a flat, clean surface for the strip metal weld bonding.

 

[flatline]

Yes. To make sure you have even contact surfaces in applications, and for when I re-spot weld battery tabs & balance leads, I need a flat, clean surface for the strip metal weld bonding.

My MG L-mini II's have springs at both ends of the battery, so I'm confident that it's making a good contact.

I'll never use these cells in a multi-cell configuration, so I don't have to worry about good connections between cells. Just the connections at either end of the battery tube.

It sounds like you're doing some really interesting things with your cells. If you don't mind me asking, could you describe some of your projects?

--flatline

 

[stu929]

First I would like to say Im new to higher end flashlights and do not know a ton about the subject

I pulled 12 of these out of an old pack that I had. Charged them they all drop back down to right around 3.8-3.92. I tried to do a run time test but I was concerned about discharging the cells to far. That being said my 3.9v battery was still at 3.8+ after running for an hour with an R2 drop-in on high.

While not optimal how long would you think these would serve me and how much am I giving up by them not staying charged to the full 4.2v? What kind of run times can I expect with these?

I'm currently driving some DX drop ins from C2 and other hosts with them.

Thanks

 

[Lion251]

I also harvested some (9) old cells from a laptop pack.
The cells were originally 1500 or 1600 mAh (I don't have them here at the moment), and about 1000 mAh remain.
From the discharge voltage curve it seems that these are still cells with cokes instead of graphite (voltage dropping more quickly than with modern cells, at 3,5V quite a lot of charge is remaining).
But now for the strange part: they keep their charging voltage remarkably well. A cell that is charged to 4.20 V will, after two weeks(!) still show 4.19 or 4.18V.
I intend to use these cells in a very low drain application, where they need to keep their charge for maybe a year or so, static current draw will be 2 uA, with an episode (seconds to minutes) of 50 mA every few days.
I think these cells can do that, but isn't it unusual that cells this old still keep their voltage so well?

 

[jellydonut]

I ripped open an OEM replacement pack from some no-name company the other day as its host laptop was destined to the scrapyard. The 18650s inside were 700mAh at most when new so really just something I did to see if it could be done. The metal tabs were easy to twist off by grabbing them and twisting to one side with a plier. Same as one would do on the cap covers on oil drums really.

 

[etc]

I have about a 100 of 18650 cells from various cell packs.

About half Green ones, with the capacity of only 1800 mAh. It has to be even less than that now.

I only have about a dozen that are even 2600 mAh.

 

[dwestonh]

Thanks for the hint on clear 3m packing tape. Now I will not try to get all the stickiness off the two sided tape.
Just wrap it up. I was using a teflon pan scraper. Now I am set to go. Next I will start labeling before wrapping.
Maybe instead of "from the library of" , "free battery salvaged from laptop"
Now I will have to decide how many spare batteries per flashlight.
Good thing I can sneak off to going gear without the wife catching me.
Maybe a walking stick battery holder with much springs on both ends.
Maybe one of those. Walkers for old folks, that should hold more.
Fifty round shotshell bandoliers. I think that would be a start.

 

[Cypher_Aod]

about two years ago i disassembled a thinkpad battery-pack (a cheap chinese replacement actually) with the intent of replacing the cells, but i never got around to it.
the six cells had been sitting on my windowsill, in the rain, breeze, sun and dust ever since.

i realised about three hours ago that, as 18650 cells, i might be able to use them in my lights, so i separated them, removed all the welded connector-tags and checked them all with a multimeter, and despite them having been sitting there for two years every single one of them was 4.05V or higher (4.05, 4.05, 4.07, 4.08, 4.08, 4.08)

one of the cells was dented/deformed at the bottom, so i threw it away, but the other five appear to be healthy, they all seem to power my lights up just fine (including my 2.8A XM-L)
the Cells have CGR18650AF on the side, which i googled and saw means that they are (or were) Panasonic 2050mAh cells with a 4A max discharge current.

i don't currently have a 18650 charger, but otherwise do you guys think that they're likely to be safe to use?

Also, can someone recommend me a 18650-charger, preferably affordable? is the "Ultrafire WF 139 Charger" from flashaholics.co.uk any good?

 

[HooNz]

about two years ago i disassembled a thinkpad battery-pack (a cheap chinese replacement actually) with the intent of replacing the cells, but i never got around to it.
the six cells had been sitting on my windowsill, in the rain, breeze, sun and dust ever since.

i realised about three hours ago that, as 18650 cells, i might be able to use them in my lights, so i separated them, removed all the welded connector-tags and checked them all with a multimeter, and despite them having been sitting there for two years every single one of them was 4.05V or higher (4.05, 4.05, 4.07, 4.08, 4.08, 4.08)

one of the cells was dented/deformed at the bottom, so i threw it away, but the other five appear to be healthy, they all seem to power my lights up just fine (including my 2.8A XM-L)
the Cells have CGR18650AF on the side, which i googled and saw means that they are (or were) Panasonic 2050mAh cells with a 4A max discharge current.

i don't currently have a 18650 charger, but otherwise do you guys think that they're likely to be safe to use?

Also, can someone recommend me a 18650-charger, preferably affordable? is the "Ultrafire WF 139 Charger" from flashaholics.co.uk any good?

Sun ? in London , your pulling my leg , but WoW , thats a advert for brand longevity .

 

[Cypher_Aod]

We get Sun in London quite frequently actually. it's just everywhere else in the UK that's permanently overcast

 

[HooNz]

We get Sun in London quite frequently actually. it's just everywhere else in the UK that's permanently overcast

I would like proof of this event :naughty: , just what day did it happen , or what actual year , the actual hour of sunshine would be interesting information also .
Was the event reported in the newspapers ?

:thumbsup:

 

[Cypher_Aod]

Photo's will be posted as soon as the sun comes up

Photos of our glorious London sunshine:

This is me!

My Charger (Xtar WP2) arrived today, charged all the cells up from their 4.05-ish levels till the charger decided they were full at 4.15V they didn't get even the slightest bit warm during the charge, that said, it only took about 25-35 minutes for each cell to finish.

I tested one of them in my XM-L monster on max (2.88A draw!) - i had it on for at least half an hour, maybe more (wasn't keeping track of time, did it in three bursts) and the cell read 3.79V after a 15 minute rest after the abuse - very impressive, the cell didn't even get warm from the draw!

most of the cells are now reading 4.14V about an hour after they were charged... is this normal?

 

[cdrake261]

Crap...and I just got rid of 4 laptop batteries last month

 

[kramer5150]

about two years ago i disassembled a thinkpad battery-pack (a cheap chinese replacement actually) with the intent of replacing the cells, but i never got around to it.
the six cells had been sitting on my windowsill, in the rain, breeze, sun and dust ever since.

i realised about three hours ago that, as 18650 cells, i might be able to use them in my lights, so i separated them, removed all the welded connector-tags and checked them all with a multimeter, and despite them having been sitting there for two years every single one of them was 4.05V or higher (4.05, 4.05, 4.07, 4.08, 4.08, 4.08)

one of the cells was dented/deformed at the bottom, so i threw it away, but the other five appear to be healthy, they all seem to power my lights up just fine (including my 2.8A XM-L)
the Cells have CGR18650AF on the side, which i googled and saw means that they are (or were) Panasonic 2050mAh cells with a 4A max discharge current.

Sorry to resurrect an ancient thread... but this does not surprise me one bit. The Panasonic CGR18650 cells I have can hold a charge for at least 8-9 months (the longest I have ever tested them) at 4.15V or higher. The hold a charge longer/better than the Samsung, Sony and Sanyo cells I have tested. That probably one of the reasons AW uses panasonics for his non-IMR cells (my understanding).

 

[sxl168]

In addition to the many rules posted here for using laptop cells, I have a few comments from the past 2 years of recovering laptop batteries. 2.5 volts is a good low voltage threshold for safety circuits, however I have found 1.50 volts to be the absolute limit for cell cutoff extracting from packs. One way I test cells that suffer from low voltage is to charge the cell at 0.05C until the cell reaches 3.0 volts. Once there, remove the cell from charger and let stand for a week. If it falls back below 2.0 volts, it's a dud, if it's above that, most likely no damage has been done and can be charged normally after that. I have come to this conclusion after evaluating >500 cells and having fully cycled every one of those cells for capacity check. The only exception to this is if you accidentally short a cell trying to extract it while it was under 2.5 volts. It may very well be a good cell even though it reads under 1.5 volts. Just use the above procedure to check it. One nice advantage for this test is that there is almost no risk of fire as the energy stored in the cell for this test is almost nil, the big reason I prefer to do the leakage test at low charge instead of full charge listed in this thread. The charge leakage in the 2.0-3.0 volt range is also highly sensitive as the cell generally only takes on about 50-100 mAh in that range. A leakage rate of a hundred microamps will be easily noticed over a week. The full charge leakage test is a good second test however, if it passed the low voltage leakage test.

One other thing I didn't see mentioned is that even though cells are found which have good voltage, this in no way means the cell is useful. A capacity and internal resistance check should be done on each individual cell before using them. Any cells having under 75% of nameplate capacity will have really high internal resistance and should not be used. Roughly speaking from my 500 or so cells 60 or so were shorted or read under 1.50 Volts. 150 or so had a good voltage but failed the 75% capacity check. 100 or so that read between 75% and 90%, and the rest act if brand new never used.

I you happen to find a pack with foil cells in them, any cells that have "ballooned" should never be used. I have dissected several of these to see the insides and extract the Cobalt from the electrodes. After close examination, I saw some metallic lithium had plated onto the plastic separator (This is very bad as metallic Lithium should never be present in a normally operating Li-Ion). After being exposed to the air for 20 sec or so, the separator spontaneously caught fire where the metallic Lithium was, just a warning for that. These were from Apple Macbooks A1185 batteries. Some of those were known to have faulty protection circuits. BTW, If anyone else decides to see the insides of a cell, make sure the cell is fully discharged before doing so (<2.5 volts) and do it outside oo:. Do not short the cells to discharge as the thermal protector may trip and the cell will still be charged.

As a side note to the above posters, I too have to agree that the Panasonic cells are really good as I have had an orange set that I had taken out of a pack back in 2005 which sat in storage until a few weeks back when I decided to test them again. They were stored at 3.82 volts when I put them in storage at room temperature, after storage they read 3.78 and had >95% of nameplate capacity after testing them. Pretty darn amazing, IMO.

 

[ico]

I opened the battery of a Dell Inspiron some time ago and it has a different kind of battery source. Its not 18650's since they were rectangular and about 4-6mm thick. What kind of batteries are those?

 

[cdrake261]

I opened the battery of a Dell Inspiron some time ago and it has a different kind of battery source. Its not 18650's since they were rectangular and about 4-6mm thick. What kind of batteries are those?

do they look like these?

Somebody suggested poly ion batteries

 

[Cypher_Aod]

Sorry to resurrect an ancient thread... but this does not surprise me one bit. The Panasonic CGR18650 cells I have can hold a charge for at least 8-9 months (the longest I have ever tested them) at 4.15V or higher. The hold a charge longer/better than the Samsung, Sony and Sanyo cells I have tested. That probably one of the reasons AW uses panasonics for his non-IMR cells (my understanding).

Good to know! I'm fairly sure that if I ever actually buy any 18650s they'll be Panasonics or AWs

In addition to the many rules posted here for using laptop cells, I have a few comments from the past 2 years of recovering laptop batteries. 2.5 volts is a good low voltage threshold for safety circuits, however I have found 1.50 volts to be the absolute limit for cell cutoff extracting from packs. One way I test cells that suffer from low voltage is to charge the cell at 0.05C until the cell reaches 3.0 volts. Once there, remove the cell from charger and let stand for a week. If it falls back below 2.0 volts, it's a dud, if it's above that, most likely no damage has been done and can be charged normally after that. I have come to this conclusion after evaluating >500 cells and having fully cycled every one of those cells for capacity check. The only exception to this is if you accidentally short a cell trying to extract it while it was under 2.5 volts. It may very well be a good cell even though it reads under 1.5 volts. Just use the above procedure to check it. One nice advantage for this test is that there is almost no risk of fire as the energy stored in the cell for this test is almost nil, the big reason I prefer to do the leakage test at low charge instead of full charge listed in this thread. The charge leakage in the 2.0-3.0 volt range is also highly sensitive as the cell generally only takes on about 50-100 mAh in that range. A leakage rate of a hundred microamps will be easily noticed over a week. The full charge leakage test is a good second test however, if it passed the low voltage leakage test.

One other thing I didn't see mentioned is that even though cells are found which have good voltage, this in no way means the cell is useful. A capacity and internal resistance check should be done on each individual cell before using them. Any cells having under 75% of nameplate capacity will have really high internal resistance and should not be used. Roughly speaking from my 500 or so cells 60 or so were shorted or read under 1.50 Volts. 150 or so had a good voltage but failed the 75% capacity check. 100 or so that read between 75% and 90%, and the rest act if brand new never used.

I you happen to find a pack with foil cells in them, any cells that have "ballooned" should never be used. I have dissected several of these to see the insides and extract the Cobalt from the electrodes. After close examination, I saw some metallic lithium had plated onto the plastic separator (This is very bad as metallic Lithium should never be present in a normally operating Li-Ion). After being exposed to the air for 20 sec or so, the separator spontaneously caught fire where the metallic Lithium was, just a warning for that. These were from Apple Macbooks A1185 batteries. Some of those were known to have faulty protection circuits. BTW, If anyone else decides to see the insides of a cell, make sure the cell is fully discharged before doing so (<2.5 volts) and do it outside oo:. Do not short the cells to discharge as the thermal protector may trip and the cell will still be charged.

As a side note to the above posters, I too have to agree that the Panasonic cells are really good as I have had an orange set that I had taken out of a pack back in 2005 which sat in storage until a few weeks back when I decided to test them again. They were stored at 3.82 volts when I put them in storage at room temperature, after storage they read 3.78 and had >95% of nameplate capacity after testing them. Pretty darn amazing, IMO.

Beautiful post and wonderful advice! Again, panasonic cells definitely sound tops

I opened the battery of a Dell Inspiron some time ago and it has a different kind of battery source. Its not 18650's since they were rectangular and about 4-6mm thick. What kind of batteries are those?

do they look like these?

Somebody suggested poly ion batteries

Those are Lithium-Polymer cells


Sent from my HTC Vision using Tapatalk

 

[ico]

Nope. What I saw were color white rectangles 6 inches long by < 1 inches wide. They were packed like wafers side by side. the battery pack is about 6 inches long and 2 inches wide only. I think there were about 4-5 wafer like batteries inside since they were placed side by side. I'll try to post a pic after my exams.