Probably a series/parallel combo. Like 3 cells in parallel with 4 groups of 3 cells in series. If that's the case, they're 1800mAh cells. Old indeed.
I got some recycled packs a couple days ago. One of them had cells that looked like cell phone batteries. Around 1.75" x 2" or something. They're in the garage so I don't have a pic atm.
The rest of the packs revealed these:
Look at the wasted space in the green cell pack. Cheapskates! 3 of the 4 green ones had 3.2v while the 4th had 2.3v. Anyone know what kind of cells these green ones are? Manualman, I think I got those same Sony cells with piss-poor voltage. Mine are electric bluish in color. All of them had 2.3-2.4v. I'm going to charge one and see if it holds charge. The purple ones got me excited since they're Panasonic 17670's (which I need), but 7/8 had ZERO volts. And that 8th cell had 1.8 volts. lol, oh well. The best cells were the blue LG cells. All of them were 3.8-3.9v. Looks like I got 6 used cells for $6.00 and some prying power.
Yes, I don't know why I didn't think of that... It seems so obvious now (hind sight is a wonderful thing). If they are 1800mAh batteries then my guess is that they are from about 2006-2007.
Edit: I think the blue Sony cells you mentioned are 2200mAh... I think I recall someone on CPF mentioning them.
As for charging up cells below the 3v threshold there is thread about this here: http://www.candlepowerforums.com/vb/showthread.php?229717-Low-voltage-on-18650-cell I am going to try charge a couple of the Sony cells as well..but they will be charged outside and put through their paces before I even contemplate using them as I would any other cell.
As for the green cells I believe they are Panasonic cells. Check Panasonic .com and put in the battery type and letter ie CGR18650AF and you'll find they are 2050mAh
I decided to solder some blobs? on my lap top batteries. I was warned against doing it but was careful. I put some flux on the top of the battery. Put plenty of solder on the tip and just dropped a small blob on the top of the battery. I then cooled them in a small amount of water. Tested all 10 and they worked fine. I needed to do it to run my ufh3.Most protected batteries (tf Flame just works) won't fit and you need a nob on he positive end to make contact.
If my flat-top cells don't make contact in a flashlight, I usually just use a small screwdriver and gently pry up the vents about 1 or 2mm.
Works! :)
Another maybe better solution, because you could not damage the cells, are to use small magnets on the batteries for example these of DX: 20 Pack on DX for $3,40
I don't know if it's a better solution. With magnets you can get shorts depending on the setup of each flashlight if the magnet slides. And if you actually use your flashlight and drop it a couple of times from 1m it makes that flat button recessed.
I have the 8mm magnets. Won't work in a lot of situations as the contact point is less than 8mm.
anyone recycle some brand new packs ? 9 cells for 20$ seems good to me 
could be 3900 mah batteries
It could be good but it could also be a POS.
Is there a way to know which ones are this kind of junk?
Like, for instance, will they charge up extremely quickly? Or heat up excessively during charge?
Where else can the energy go if it takes just as long to charge up, and doesn’t heat up?? :~
So that Acer Aspire 9 cell. That’s 7800 mah divided by 9 is 866.67 mah per cell? that’s pretty low for 18650. Taking from this example. Acer Aspire One on Ebay 9 cell 7800mah That’s roughly 3.02 per cell. Just a 30 second search on ebay got me these. Set of 3 x 3.6v 18650 Li-Ion Rechargeable Batteries 2200mAh ( 6600mAh) w/tabs which equals 1.67 per cell.
No!!
That is 7800/3=2600mAh per cell
Doesn’t work that way. It is 7800mah at 11.2V (or whatever the voltage of the battery is). Hence it is probably a 3S3P config, and you divide 7800 by 3 to get 2600.