I was wondering which laptop battery pack yields the best unprotected 18650’s, there is a recycle place close by where I can get a hold of a variety of used laptop battery packs for practically free, just want to know what to look for.
Any tips?
Well, you can use a little math to figure out what the capacity of the individual cells is. The battery will first have to be a lithium ion battery (of course). Most likely, they will be 11.1v, meaning that there are at least 3 cells in series (3.7*3). If the battery says 6-cell, then its 3 pairs of 18650’s in parallel, 9-cell means 3 sets of 3 18650’s in parallel.
So now, look at the capacity. If it’s measured in mah, then it’s pretty easy. Let’s take a 7200mah, 9 cell, battery (at 11.1v). This ends up being 21600 at 3.7v, and you have 9 cells, so you’re looking at 9 2400mah 18650 cells inside.
If the capacity is measured in watt-hours, then it’s basically the same thing. So a 9 cell, 84 watt/hour battery. Devide the watt/hours by the voltage(11.1) and you’ll get 7567mah.
Of course, the newer the better. Once you get the cells apart, make sure to test that they are above 3V or so using your DMM. Please seek out and read what others have written about determining what is a good vs a throw away cell from a reclaimed battery.
Thanks for the tips Ryan! I have a Turnigy charger and will run capacity tests on the cells to find the good ones to keep. I was more interested in brands of battery packs like dell, sony etc. that members have opened up and found to carry name brand quality cells inside.
The Dells and Acers I have opened yielded 2050 and 2250 mAh panasonics which, for free, is great!
Most name brand packs have name brand cells in. I have had good luck with dell batteries. They often have 2600 mah sanyo batteries in them.
Thanks for starting this alex was just wondering the same thing
Posted on iphone
For example:
The Toshiba Qosmio x505 series uses a 12 cell 90 watt battery pack stuffed full of good Panasonic cells.
I want to wish you a warm welcome to BLF, ryanferg!
I get HP, Dell, Acer,etc…… what ever is there. When I started out was checking every cell. Got to decide for yourself what parameters are acceptable, mine were skipping any cells that are not at least 2400ma original capacity and have at least 80%+ capacity. First thing is pull the big sticker off and removing the thin plastic covers. This is a major time saver as there is access to the cells (not all but most) with the least amount of effort as in busting open the pack. This allows identification of cells and DMM access to check voltage. From there toss them or proceed to dismantle, charging & checking. It’s not for everyone and kind of like fishing with good and bad days.
I'm typing this on a Qosmio x775 as we speak - it's good to know I could cannibalize her pack, if the SHTF. 
Off-topic: the "brick" (charger) for this computer is literally a brick; it's the largest I've ever seen, period. I guess it needs to be large, outputting 19V at up to 9.5A... 
if you want to be selective, go for the ones most recently manufactured. Doesn’t matter what cells are inside if they’re dead, lost 1/2 their capacity or self-discharge like crazy. Or just take all of them, test all of them and take back all the duff ones. My hit rate is probably ~15%, with no rhyme or reason as to brand name packs vs. generic, brand name cells or plain wrappers.
As Mr. Gump said; “life’s like a box of chocolates”
+1 About 1 in 8 for me. Had a run on good Samsung pink 2600s like 15 good cells like almost new capacity over a month period. Used 12 for a 4s3p HID pack. Been dry lately but haven’t been hitting the bins as hard. Have plenty for FL use at the moment.
So just where is everyone finding these battery packs?
I get mine from E recyclers, costs them money to recycle them so they give them to me free :bigsmile:
Obviously the newer the better however most battery packs I get are 2400 or 2600mAh cells. Dell and Lenovo packs yield the best I have found so far (Sanyo 2600mAh).
Battery manufactures I have found so far:
Samsung
Sony
LG
Sanyo
FHG (or something…. Chinese apparently)
From:
Dell
Lenovo
HP (mostly Sony 2600mA green (past it))
Acer
Toshiba
No Panasonic yet 
I get mine from recycling bins around campus or the workshop in the next building. I’ve found Panasonics before, in older Macbook batteries (’05 ish), but almost all of them were toast or self-discharged. I have a couple that are decent.
So far I’ve never had a salvaged cell above 2Ah. Still useful, but if I need high capacity I’d rather buy new.
OK RF,
I just pillaged a Laptop pack with 8 LG Salmon colored cells inside.
2 Cells low voltage = Recycled responsibly 
6 Cells Good range charging now.
Pack states 14.8v & 4.4Ahr
14.8v/3.7v per battery = 4 x 4.4Ahr = 17.6 total Ahr / 8 batteries in pack = 2.2 mAh per battery??
Must be close, all the numbers came out even.
Now if I can figure a way to tell how much life is left in these, or any battery I have…….
Thanks for the help
it’s a bit simpler than that. If you have a 14.8V pack, you have 4 cells in series (4S). If you have 4 cells total in your pack, it’s 4 series 1 parallel (4S1P), so the pack Ah rating is that same as 1 cell (more cells in series = higher voltage, same Ah). If you have 8 cells, it means that they’re 4S2P. Doubling the cells in parallel (1P to 2P, for example) doubles the Ah of the pack. So if you know the Ah rating of the pack, divide it by two to get the capacity of the individual cells.
so, 4.4Ah pack in 4S2P = 4.4/2 = 2.2Ah per cell.
You all make it sound soooo simple…lol.
Before cracking open the cases, I suppose we could estimate the number of cells and mAh of the batteries by numerical bracketing. This may help choosing the potential quality of the cells inside.
Thank For the help
yup. If it’s 14.8V it’s 4S, if it’s 11.1V it’s 3S. If the capacity is over 2.9Ah or so, then it’s 2P. Most laptop cells are 2.2 to 2.9Ah in capacity.
I just salvaged 13 battery packs. I didn’t keep good track of which cells came from which pack because it seems really random. I had planned to note the name of the laptop and which cells I found in which packs.
I had 5-6 HP packs that were all very similar if not identical. Several must have been from the same model of laptop. After cracking them open, I found different cells in the packs. I expected to find pretty much all the same cells in the HP packs but it was not the case at all.
My point is, any advice about which cells are in which packs is going to be more a guideline than a hard and fast rule.
Probably the easiest way is just look at the pack. The bigger the pack, the more cells it probably contains. I had one large pack that contained 12 cells.