What batteries are in the Fujitsu E8110 battery pack? It is 6 cells and 5200 mah and it says 10.8 volts
Should be 2600mah, 6 of them haven’t the clue as to brand maybe sanyo.
I am wonder how calculate the capacity of some laptop batteries with 5200mAh, 7800mAh.
Need to know the voltage and number of cells to be certain. Should be 2600mAh cells though.
As an example, if the laptop battery pack has a capacity of 5200mAh, and has 14.4V output (3.6V x 4, series, 2-banks) and the 5200mAh capacity comes from the 5200/2=2600mAh cells. So most probably it is a 4S, 2P connected, 8-cell (2600mAh) battery pack.
It is so awesome that buy laptop battery to get 18650 batteries.
laptop pulls /can/ be a good way to get cheap cells if you are vigilent and careful. wouldn’t use them in anything but projects, or my cheapie $11 xml zoomie though, as the last thing I need is a unsound battery wrecking one of my ‘good’ lights.
charge to 4.21v, then discharge to 2.9v, and repeat 3-5 x. if the results are fairly uniform you got ‘new’ cells that were stored a long time.
In the long term not much difference at all… the cells will eventually all wind up in the landfill/recycle center someday. Also if the packs are sent to a recycle center intact, the housing will probably be recycled. I bet 90% of the people that salvage laptop cells put the housings in the trash.
The truest sense of the word recycle should be to use what still has useful life instead of tossing it into a land fill . It actually is good for the environment as something else doesn't need to be produced and landfilled until the full use of these cells is over . the premature tossing of battery packs is the reason laptop pulls have any viability for us as flashlight enthusists.
When some assistant manager at a home depot refuses to let you dig around in the recycling bin use this logic against him .
The truest sense of the word recycle should be to re-use.. not toss .
In the immortal words of Monty Python ..>
I'm not dead yet ..
Thought I might update this for someone who might be interested how the laptop pulls are doing.
This cell one month and a week from charging is measuring 4.16v 
Thanks for the update moderator007. Mine are doing great too. This was a good find ohaya. 
You’re welcome!
If you recall, it was touch-and-go for awhile because of the initial battery voltages, but I’m glad they worked out well for you all!
Ohaya;
I have sold hundreds of Panasonic cells (currently 3400mah).
The cells date code indicate produced in 2009.
They are ~ 4 yrs. old.
Typical life should be 5 years whether used or not.
So you should have some life left in those cells.
LarryDFW
LarryDFW wrote:
Ohaya;
I have sold hundreds of Panasonic cells (currently 3400mah).
The cells date code indicate produced in 2009.
They are ~ 4 yrs. old.
Typical life should be 5 years whether used or not.
So you should have some life left in those cells.
LarryDFW
Hi LarryDFW. Welcome to the forum. That is one of the "accepted truths" that this thread may disprove. This thread is long, but you may find it interesting given that you sell/sold Li-ions.
Hey Ohaya. Mine are still be having like "new" cells. I trust them so much that I have even been using them in series for about a month now. I don't recommend that others do the same unless they continually monitor the health and capacity of their cells. Something that should be done anyway when using even actual new cells in series.
Thanks. This was, I think, one of the first, and best, packs I’ve found, and I’m glad they are working out for you all.
We were curious when ohaya alerted us to these old, but unused stock pack how these cells would hold up over time. I've been testing mine the last couple days and most still measure in the 2700's and 2800's and have decent internal resistance (Most in the 20's, but few are higher with one hitting 81). The resistance measurements are the average of two reading while fully charged using a LE500.
i have and like series flashlights. i have also been using ncr18650 2900 laptop pulls. most of the ncr cells are in great shape. i group them by like date code and then treat them identically in pairs. use, charge, etc.
absolutely no issues.
not imr cells but they can take a beating just fine. as an fyi note the factory discharge rate specs.
A long awaited update:
These cells have a date code of CY9926, September 2009. I purchased them early in 2013 from this thread. I tested one using my hobby charger at a 3 amp load down to 2.7v on 4-22-2013.
The graph is above at post #155
I got 2740 mah out of this never been used 4 year old cell at 3 amps. I charged the cell back to 4.2v and it’s been setting for 6 years.
I pulled the cell out a few days ago and measured the voltage at 4.01 volts. Charged the cell up to 4.2v and ran another test at a 3 amp load down to 2.7v.
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The charger has to be set to Nimh to get a 2.7v termination. Li-ion setting doesn’t go any lower than 3.0v.
I got 2703 mah. I’m sure if I had ran another cycle that the mah would be right at that 2740 I tested it to be 6 years ago.
So what’s going on here, this is a 10 year old cell and seems like new. Has everything I been told or read about li-ion low voltages been a lie.
Pic of the date code for proof and shows the IR measurement.
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I don’t think that a lot of information and datasheets can be trusted to be accurate since we are not using them in the manner in which they specify.
All these batteries are not meant or tested to set around for a month or a year or maybe 10 years not being used. So this test gives a little insight into what happens if a cell sets unused for long periods of time and is used very little. All the battery experts would tell you this cell is junk, throw it away. Surprise “It’s like New” 
To understand this Data you will have to skim through the entire thread. The batteries being discussed here, were new never used 4 years old (now 10 years) and came with a cell voltage for most of us measuring 1.9v.
I may test this battery again in a few years.
It’s like Comfychair once said “it’s as if these cells were just taking a little nap”
Nice results, thanks for sharing. Very interesting & useful results too I might add.
That’s great info.
I pulled 6 of this from a used fujitsu laptop pack few years back, charge them full and basically put them in 1 of my drawers and forget abt it till few days ago when i chance upon them and all still measure >4V, really quality cells these fujitsu/panasonic battery.
1 Thank