BLF Community Battery Pulls Overview Thread (Laptop packs and Tool Packs)

Nice score. Those cells aren't 1450mAh, they're 2900mAh!

thanks for the post MIKE C and Otanacious is right, those are 2900mAH cells and OP updated

Oh? The battery pack had a rating of 8700 mAh on it. Divide that by 6 and it’s 1450. Is it common that battery pack ratings are not the same as cell ratings?

your math was a little wrong, you needed to divide by 3 not 6

I looked up what voltage those packs the EeePC use run at, and they state 7.4V, and 3.7V nominal in 2S is 7.4V. Also I assumed the configuration is 2S3P after seeing the pictorial proof and capacity rating. In the end 8700/3 = 2900.

Now I want to go out and hunt for those high Wh/mAh 2S3P packs since I've never tore one open yet

Of coarse! Didn’t think of that at all. Thanks.

I’ve updated my post that you link to. Thanks.

thanks Mike C

I did a laptop pull recently, a Lenovo 45N1173, 10.8V 8.7Ah - 94 Wh. I got 9 cells, all measured at 4.08V. I think it is Panasonic 2900mah.

i will get this added asap thanks

Nice thread guys! Sticky’d.

A few days ago I tore apart a battery pack previously installed in an ASUS K52J series. The pack was rated for 11.1V 5200mAh and the cells inside were LGs. Specific model: LGABB41865 2600mAh

2 of them show 0V, I will put them in the battery recycling bins.
2 of them show 3,66V.
2 of them start off at 3,5V and then drop and drop and drop until they reach zero. They reach 0 volts after 10 seconds of measuring. I have disassembled a few packs and I’ve never seen such behavior. I’m measuring the voltage using a Fluke multimeter. Anybody has any explanation for this weird cell behavior?

that is a little wierd to just drop to 0 volts after a few seconds, i have never run into that. But i will update op with your findings.

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.