That was the remnants of their ‘electrical soul’. You sucked it right out and killed them. :bigsmile:
Take a look at the fall off curve on lithium. These batteries were essentially dead and on the last tiny bit of the vertical component of their discharge.
You can do the reverse > take a freshly ‘dead’ battery, charge it for just a bit on a low amp NiXX circuit and it will rapidly bounce up to 2-3v but there is still essentially no capacity there.
Did my first battery pull today. HP 437403-541 met it's end. Unfortunately I do not own a multimeter so no voltage test for now. But I should be able to measure it at work.
As you will be able to see in the photos I found Samsung ICR18650-26C (Samsung SDI 775) batteries inside. Their data sheet says:
Samsung SDI ICR18650-26C
Nominal Voltage 3.6V
Nominal Capacity 2600mAh
Lithium Contents 0.78g
3.6V surprised me a bit, I expected 3.7V. Or is it normal?
Update:
One set of 3 showed 2V, other - 2.65V. Hopefully I'll be able to charge them.
thanks kaiser, updated OP with your pull.
That’s odd. Where did you come up with 3.6v? I found an MSDS from HP that lists these cells as 3.6v, but the Samsung datasheets out there list them as 3.7v. Looks like HP is using the 3.6v value on the pack too, since it is marked as a 7.2v pack. I wonder what it reports to the system over SMBus for both nominal voltage and capacity.
Just Googled markings on cell and found their data sheet on HP’s website. Probably the same you were looking at. Won’t be able to tell what it reports to the system because it’s a random battery I purchased on internet.
One of the newer packs I have opened.
Contained 9 Samsung 26C. My favorite cells.
good post kyfishguy, i have a dell to open up this weekend, if my guess is correct it will be icr 29’s
i will get the chart updated asap.
I dropped by the retail store of a PC recycling shop yesterday and picked up some used packs for $1 each. Pickings were pretty slim and mostly DELL from the late 2000s. I am pretty turned off Dell after the shitty quality and poor yield of a bunch of 6-cell packs I took apart a few weeks ago, but I’d made the trip, so I decided to pick up 5 packs and get a broader view of Dell’s battery pack engineering.
The first of two Dell Type TC030, 11.1v, 85 Wh packs I tore into was labeled as having Korean cells. Once I got the pack open, I saw they were teal LGDB118650 cells, which are rated at 2,600 mAh capacity. They were arranged as 3s3p.
The voltage of the pack, measured with a multimeter was 8.25v. The individual banks, starting from the positive end of the pack were 3.78v, 0.8v and 3.70v. When I pulled the first bank of cells apart, I found that the welds were strong and intact, but I saw the problems I saw with the earlier 6-cell packs: The cell voltages within a bank weren’t uniform. Two were ~3.78v, but one was 0.12v.
Concerned that I might have been breaking an internal weld when tearing the nickle strips free at the negative end, I took more care with the next two banks, disconnecting the positive terminals and measuring voltages before tearing the strips at the negative end. Even so, each bank contained cells with major variations in voltage, something that shouldn’t be happening.
Out of 9 cells in the pack, only 4 had voltages above 2v. I’ve run them through a charge/discharge cycle @500mA on my Opus and they all have about 1,500mAh capacity, or just 57% the original rated capacity. Update: it looks like these cells are supposed to be charged to 4.35v. I can’t find any comparisons of how much capacity is sacrificed by charging to 4.2 for these specific cells, but it looks like other LG cells give up 10-15%, which would put these at 1,660-1,750mAh, or 2/3rds of the original capacity.
According to PackProbe, the pack has seen 186 cycles, and was manufactured in the summer of 2007. This seems to me to be above average wear-and-tear, perhaps not surprising given that all the banks had at least one bad cell and are 7 years old. The datasheet for these cells indicates that they should retain 75% of original capacity after 300 cycles.
I have started tearing apart a superficially identical pack that is marked as made in Japan. It’s actually quite different.
Oh wow I didn't know these were 4.35v cells. It probably explains why they come out to that capacity range when I ran a set through my Lii-260 (far right).
Tore apart my old Gateway battery that I have replaced. The nonfunctional SQU-715 yielded 6 Blue LG 18650 cells labeled LGD5318650.
Right out of the pack each cell tested at over 4v and have taken a full charge from my OmniDok.
I don’t have a way to test the capacity of each cell, nor do I currently have a way to test them. I’ll edit it when I get my Opus in and can do a capacity test.
any more specs on the laptop battery?
Well 6 cells in 2 rows of 3. The battery was rated 4400mAh. So I’d suspect these are 2200mAh cells.
thank you, i will get the OP updated asap
I think I may have done this, one of these measured 0 amps.
I usually peel the strips off with needlenose pliers, like opening a sardine can.
Next time I’ll be more delicate.
.
I can’t say whether or not that is likely to damage the cells, but after taking more care in tearing apart more packs, I’m certain that, at least in the Dell packs with LG and Samsung cells assembled in China by SMP, there is some other reason for the dead cells, because I’ve had multiple such packs with dead cells in parallel with non-dead cells where I’ve measured the cell voltage before tearing off the strip on the nickel end.
At this point, I’m really down on Dell packs, at least the 4+ year old ones. The ones assembled in China have been mostly dead cells, and even the Sanyo assembled packs with Sanyo cells seem below par and have weird design decisions that seem at risk of subjecting parallel cells to different electrical conditions (I may be grasping at straws here for reasons to explain uneven wear).
Just tore apart (peeled the sticker off and the whole case separated) a Dell Latitude P/N 3149C Made in Japan.
14.4V 3000 mAh 8 cells. All had over 3 volts.
Sony Energytec STG US18650S H2
Are these the ones that used to catch fire?
UN 356S1-S1 Laptop Battery Pack.
Rating: 11.1 Vdc
6000 mAh
9 Light Blue Samsung ICR 18650-20 all at 3.72 volts.
was this for an advent or vega product?
Took apart a Dell Inspiron battery pack - J1KND (11.1V; 4400mah; 48Wh). This one was a lot harder to open than my first HP battery pack.
LG LGDAS31865 2200mAH (10A ?) 3.7v cells inside.
Edit: all 6 cells measured ~3,9V. So not bad I guess.
Coming back to my previous pull. 3 cells measured 2V, other 3 - 2.65V. Some guys say that it’s only safe to charge cells that are at least 3V when pulled. How much truth is there? Still waiting for TP4056 charging board I’ve ordered earlier so wasn’t able to try myself. But maybe I shouldn’t if it’s unsafe?
It was like a no name laptop that I trashed. I just made sure that I got the pack model #.
