Using cells from laptop battery.

[Marco Polo]

I have a Lenovo laptop that is less than a year old, however it had liquid spilled onto it and its status is now FUBAR. However, the RAM is still good (I now have 8 gigs in my other Lenovo) and I believe the SSD may be good as well. I just haven't gotten around to testing the SSD. (Update: SSD confirmed working, yay )

Since at this point it would be cheaper to get a new laptop than have this one fixed, I now have a 9-cell laptop battery. Judging from its size and shape, they are probably 18650's.

Has anyone ever dismantled a laptop battery and pulled the cells for use in their lasers? I'm going to be needing more 18650's soon, and wouldn't mind 9 free ones, especially since they are probably Sanyo cells.

So, any advice on doing that (without blowing myself up) would be greatly appreciated. Thanks!

ETA: I did end up extracting the cells; there were 9 LGABC21865 cells, which are LG Chem 2800mAh. Good stuff!

 

[Livinloud]

I have a bunch of Sanyo laptop pulls. Keep in mind that laptop battery cycles a lot more than you realize. They will not be to full capacity unless you killed it soon after you got it.

Crack the case open, they will be 18650s. CAREFULLY pull the packs out. They will be connected via tabs. Removed tabs or snip them to make easier to remove. BEWARE they will probably spark a little so don't freak out when it happens

 

[BShanahan14rulz]

Lenovo comes with good battery utility. Before cracking battery open, see if you can pull the stats from the utility. It will tell you even how many cycles the cells went through.

Go slow as you can, don't touch different tabs at the same time, don't touch tabs or wires together, etc.

I usually grab the tab as close to the 4 weld marks as I can with the side of the jaws of some needlenose pliers, and then roll the pliers back towards the welds to roll teh tab up off of the weld points. You will often end up with 4 raised spots from the welds. I used a dremel to quickly smooth those out, otherwise they will eat up contact boards that don't have springs.

Measure each one out of the pack, and toss any low voltage ones if there are any.

Last Lenovo cell pack I took apart was a 9 cell from an R61, contained sanyo UR18650FM. Pack also had a very very low cycle count (IIRC, somewhere around 20 cycles. Cycle life is usually ~1000 cycles) Sanyo ftmfw!

Edit: sparking should be avoided, and shouldn't happen if you are very very careful and do things right, but if you do momentarily short something for a split second, no biggie. These are strong cells. If you short and somethign starts getting uber hot, you may want to keep that cell separate or even discard just to be safe. I've a few cells that have been shorted for a few seconds, they still appear to work fine, no heating during charging, good capacity, no voltage leaking over time more than expected, but I still use them for my lower power lights. All but one of my cells is sanyo; one is a random red-wrapper IMR I bought a long time ago.

 

[Marco Polo]

There are the cells in my laptop's battery. LG cells, good stuff Probably 2600 to 2800 mAh each, judging from the battery's total capacity of 7.95Ah (or 8.4 Ah? It says both in different places...) and having 9 cells

 

[Livinloud]

search those codes and you'll see what the capacity is

 

[Marco Polo]

Well, there you have it. 9/9 cells removed intact, although 12 and 13 did have a little insulation damage due to some short-circuit action that went on (briefly) during the disassembly. I did get a little cut up in the process as well; next time I think I'll put on some gloves!

I tested each cell for internal resistance. I used the formula found in the "How healthy are your batteries?" sticky at the top of this sub-forum. My charger would not charge any of the cells at this point - apparently it won't attempt to charge unless the cell potential is less than 4.10 volts.

All cells came in at less than 200mΩ. All but three came in at less than 150mΩ.

I number all of my cells. This helps me keep straight what's what. Numbering starts at 5 because I already operate four 18650's which have numbers 1 to 4. I compared the cells to one of my original four; that cell is included in the photo and data. I compared them to an Ultrafire 2400mAh (not pictured) and that cell came in at 138mΩ.

Based upon the available information these cells are LG 2800mAh.

Advice and/or criticism on my testing method is welcome.

 

[ryansoh3]

Pro job on the laptop pull and sorting the batteries!

Thanks for documenting the process. +1

 

[Livinloud]

For Battery Aficionados (Junkies) Only! | BudgetLightForum.com

2800mAh for the orange wrapped ones, check the code on the mustard one since it might be the 4.35V version and you dont want to mix those up

 

[BShanahan14rulz]

To get a better approximation of the slope, it is a bit better to get your V1 and V2 values from points closer to the middle of the discharge curve.

Nice extraction, would expect all those to be usable, and a bonus 200mAh!

What model was that battery pack? I saw you mentioned that it was a Lenovo, and I knw they used to use Sanyo. Switched to LG, it seems.

 

[Marco Polo]

To get a better approximation of the slope, it is a bit better to get your V1 and V2 values from points closer to the middle of the discharge curve.

Nice extraction, would expect all those to be usable, and a bonus 200mAh!

What model was that battery pack? I saw you mentioned that it was a Lenovo, and I knw they used to use Sanyo. Switched to LG, it seems.

This particular battery was the 9-cell option for the Lenovo X230. The computer was a Core i5 and would run about 8 to 10 hours on a full charge. I'm still unhappy that it got liquid spilled onto it.

7950mAh is stated to be the minimum battery capacity, so true capacity should be ~8400mAh since these are evidently 2800mAh cells. I may have to put a few of them in the refrigerator so they last longer, since I now have lots of cells and not enough lasers to use them all.

 

[hwang21]

I had a lenovo thinkpad battery and it had 9 Panasonics in them :thinking:

 

[BShanahan14rulz]

I now have lots of cells and not enough lasers to use them all.

Time for to start a flashlight addiction

18650 FTW!!!

I would bet the capacity is based on a 4.25V charge termination voltage, which is the high end of the error tolerance for most charging chips.

hwang21: that would be more what I would expect, given I've only encountered Sanyo cells in Lenovo packs. We don't buy lenovo anymore, so no more lenovo packs for me. Well, really old ones. I don't want those.

 

[Marco Polo]

Update: All of the cells are performing great. Not an issue with any of them at all. A couple of them had damaged insulation that would have presented a risk of short circuit. I filled in the damaged spots with a toluene-based model glue, which is liquid but dries to form a hard, clear plastic. The damaged areas still look like metal, but when tested they give no voltage, and the resistance at that point is off the maximum scale.

I used my Dremel tool to grind off all the welds and tab remnants. These things were snagging badly on my lasers' battery springs. Now they're basically smooth and no longer give me trouble in that regard. I used the smallest diameter grinding bit I had, and the lowest speed (5000 RPM) and applied gentle pressure. You definitely don't want to over-do it and grind through the metal casing and breach the cell.

So, if your laptop gets FUBAR'ed prematurely, might as well tear up that battery and get a few extra cells. Just avoid shorting the conductors; shorting them is pretty easy to do!