Tutorial: Laptop Battery Pack 18650 Extraction

[alfreddajero]

I was lucky with mine.....it seemed that all eight of the cells work properly.

 

[csshih]

Cool Mik!
Let us know how they go.. It's cool having many different packs, you'll have many colors of cells!

Stay safe,

 

[bshanahan14rulz]

How can you tell which ones are better than the others, short of doing a runtime test, given that they all were harvested and found to be at save voltages?

 

[Lightcrazycanuck]

How can you tell which ones are better than the others, short of doing a runtime test, given that they all were harvested and found to be at save voltages?

Read post #8.

 

[flatline]

Read post #8.

Actually, I posted post #8 hoping that someone would let me know if I was on the right track. I'm certainly no authority.

--flatline

 

[zelda]

Thanks for sharing this information, some types of packs are not easy to open it without a damage/burn etc... this from lenovo are simple.

I opened a lot of T60 battery packs, ~80% had different voltage per pair. (0.1 - 0.3V difference) Normaly the electronic correct this, maybe a too big gap and the electronic shut it off,
permanently --> it can't be charged anymore in the laptop.

Removing the solder tab on anode with a plier might break a contact inside! I lost a lot of cell with this method! :hairpull:

I do this now with a dremel, grind with caution the 4 weld points.

 

[Kremer]

Actually, I posted post #8 hoping that someone would let me know if I was on the right track. I'm certainly no authority.
--flatline

That seems pretty reasonable to me. Of the 5 or so non-functional Dell laptop packs I've taken apart so far I've only tossed 4 cells. two were 0V, two were 1.xV both were paralleled sets. The remainder of the cells were 3V+ and charged right up to 4.17 on my Pila and have held within .1 of that for months after.

 

[Mik]

Just a little update on my situation. I started asking for batteries yesterday, and today I have 7 packs plus one grouping of 4 cells that a friend had already removed from the battery case. I pulled the tabs off of the 4 cells without a case, and found them to all be junk (I should have voltage tested them before pulling the tabs to see if I broke them, or they came to me bad). Two of them registered 0v, one of them is .2v and one is 3.2v. I haven't opened any of the other cases up. I think all of them that I have so far are Dell brand. 3 of them are marked "MADE IN JAPAN" and the rest say "MADE IN CHINA" and on a separate label say "CELLS MADE IN KOREA". Once I get ready to tear into the packs, I'll take pictures along the way similar to what the OP has done for us. Hopefully I am as lucky, and don't need to use the box of emergency sand.

 

[flatline]

Removing the solder tab on anode with a plier might break a contact inside! I lost a lot of cell with this method! :hairpull:

I do this now with a dremel, grind with caution the 4 weld points.

I didn't bother to remove the solder tab from the six cells I've salvaged. I just trimmed them and removed the sharp edges. My L-mini has springs for both ends of the battery, so I figure it should always make a good connection even in the presence of the solder tab.

I do have a dremel, but I'm not very confident in my skills with it. I'll wait until I have a bad cell to practice on before I attempt to grind the welds out of the soldering tab on one of my good cells.

--flatline

 

[u238]

I just pulled a bunch of these, but scuffed the wrapper of a few. The shrink wrap is incredibly thin and delicate. Can anyone think of a way to repair the wrapper?

 

[flatline]

I just pulled a bunch of these, but scuffed the wrapper of a few. The shrink wrap is incredibly thin and delicate. Can anyone think of a way to repair the wrapper?

I don't think the integrity of the cell is dependent on the wrapper, so you're probably fine just removing it if it's damaged. Just verify that the cell itself isn't damaged before you use it.

Disclaimer: don't follow my advice until others have had sufficient time to correct me if I've said something bone-headed.

--flatline

 

[kramer5150]

I just pulled a bunch of these, but scuffed the wrapper of a few. The shrink wrap is incredibly thin and delicate. Can anyone think of a way to repair the wrapper?

Yes the shrink wrap on laptop cells is VERY thin and delicate. Its been the cause of a couple fires that I have experienced, during cell extraction.

I just used 3M clear packaging tape.

Note that you can use the cell, but it will direct contact -B to the body of the light. So there is the chance that you will not be able to turn the light off. depending on how severe the damage is.

 

[u238]

Yes the shrink wrap on laptop cells is VERY thin and delicate. Its been the cause of a couple fires that I have experienced, during cell extraction.

I just used 3M clear packaging tape.

Note that you can use the cell, but it will direct contact -B to the body of the light. So there is the chance that you will not be able to turn the light off. depending on how severe the damage is.

I'm most worried about the edges at the + end peeling away while snipping the cells out of the pack has already caused some sparking for me. The packing tape is a good idea though, being much thinner than the electrical tape I was using.

 

[scriverdog]

I hope you'll indulge me with is probably a dumb question.

I have a toshiba battery pack that contains green Sony cells. I've not disassembled it yet so maybe the answer to my question will reveal itself when I do but I'll ask anyway.

as with the sanyo cells in the images posted in this thread there are no markings on the shrink wrap of the Sony's to distinguish anode and cathode.

how does one determine the positive and negative terminals of each cell ?

 

[SilverFox]

Hello Scriverdog,

Welcome to CPF.

A voltmeter works great for that.

Tom

 

[alfreddajero]

The pic on the left is the + and the pic on the right is the -.

 

[kramer5150]

I hope you'll indulge me with is probably a dumb question.

I have a toshiba battery pack that contains green Sony cells. I've not disassembled it yet so maybe the answer to my question will reveal itself when I do but I'll ask anyway.

as with the sanyo cells in the images posted in this thread there are no markings on the shrink wrap of the Sony's to distinguish anode and cathode.

how does one determine the positive and negative terminals of each cell ?

Sony greenies...

Positive

Negative

You can just use a multimeter and test for cell polarity.

Anyone doing this procedure ABSOLUTELY MUST use a multi-meter to test for cell voltage. This is a VITAL and CRITICAL safety procedure that MUST be performed if you want to reduce your likelihood of a vent/flame incident. Using cells depleted beyond ~3.25V inter-mixed with good/healthy cells can result in a vent/flame incident.

These are NOT BATTERIES, and should NOT be treated like they are. They are Lithium Ion cells, incendiary devices capable of doing severe damage and causing injury in the wrong conditions.

https://www.candlepowerforums.com/threads/262234

 

[soghol]

Is there a way to use the whole laptop battery (batteries + Pcb) as an external battery pack for a bike light.
Wondering what's the best way to charge it, is it simply just connect it with the power brick from the same laptop type, or is it more complex than that?
Thanks.

 

[Kilted]

Here's the recipe I use to determine which cells are healthy enough to be usable. If any of you see something that could be improved, please let me know (I think I'm probably being too conservative, but don't really know for sure).

1. measure cell voltage. if it's less than 2.5v, throw it away.
2. charge the cell. if it gets hot during charging, throw it away.
3. measure cell voltage off the charger. verify it's between 4.1 and 4.2v.
4. wait 30 minutes
5. measure cell voltage. if it's fallen less than 4v, throw it away. Otherwise record the voltage.
6. store cell for 3+ days in cool, dry place.
7. measure cell voltage. if cell voltage has fallen more than .1v from the recorded voltage, throw it away.

Any cell that hasn't been thrown away by the time I'm through with step 7, I keep and put into my regular cell rotation.

EDIT: I'm no authority, but since nobody tried to correct me, I'm willing to assume that there's nothing obviously wrong with the above recipe.

--flatline

I did the same thing a few years ago and finished with about 24 cells. I could not use all 24 at one time and I have a added additional steps:

8. After having been charged and on the shelf for 6 months check OC voltage and if below min. stated above discard. I cycle through all on shelf cells about every six months.
9. Check for fine crystals around the postive terminal, if you find any discard.

What do you use for a charger? I have been using a Maha C777 in LiIon mode I would like a more convient charger.

 

[flatline]

I bought the Pila charger and have had no issues at all so far. I use it for both the salvaged unprotected 18650s and for the protected 14500s I use in my Quark and LF5XT.

I'm still a bit paranoid, though. When I charge my cells, I put the charger in an open ammo can that sits on top of a granite counter near the back door. If something goes wrong, I can grab the can and throw it out the door.

Also, I only use my cells in lights that have over discharge protection (L-mini and PLI) and even then, I never run my cells below 3.7v.

--flatline