February 27, 2020

Another batch of harvested loptop batteries - February 2020

I paid another visit to an eWaste place in the city where I live. They had plenty of discarded laptop batteries and sold then to me at the price of 2 for $5. I spent $55 and got 25 (they threw in a few extras). They weigh 24 pounds 8 ounces, so I paid $2.25 per pound, or an average price of $2.20 per battery.

Use sturdy gloves when disassembling laptop packs. It is easy to slip while prying with screwdrivers and jab yourself. A dremel tool with a cutting disk is invaluable.

If each battery has 6 cells, we may get 150 cells out of this. If half of these are good, that is 75 cells, so the average cost will be about 75 cents. New brand name cells sell for $4 each, so even if these are half capacity (and they are usually better than that) this is still a great deal. We will see how this plays out.

My guideline was to buy only name brand packs, avoiding any generic replacement packs (which typically have cells from China). My luck with cells from China has typically been terrible. Some are just fine -- but why take chances?
The breakdown ended up as follows: 

Dell     12
HP        8
Toshiba   2
Panasonic 1
Compaq    1
unknown   1

My guidelines

I keep anything that measures 2.5 or higher without reservation. I discard anything that measures 2.0 or less. Cells that measure 2.0 to 2.5, I keep, mark with a black ring, and keep a close eye on. Some people say you should discard anything that measures less than 2.5 volts.

I calibrate cells using my XTAR VP4+ "Dragon" and mark their mAh capacity with a sharpie. Cells that measure 500 mAh might seem silly to hang on to, but they serve me fine in non-critical applications such as flashlights that get used briefly only now and then.

Pack 1 - unknown

This consisted of 9 cells that had already busted loose from their shell. They were 9 purple Panasonic CGR18650E cells in a 3x3 configuration. They measured 1.4, 2.4, and 2.69 volts. They are rated at 2550 mAh.

The cells measuring 1.4 were discarded. Yes, perhaps the trio measuring 2.4 should have been discarded. The 6 I kept started charging up nicely, but later during charging they began to get quite hot (133F).

I probably should just throw these out. I pulled them off the charger as soon as I noticed them getting hot. After a days "rest" they finished charging just fine in a fairly short time. They were very close to a full 4.2 volt charge when they got hot.

If they get hot again when I calibrate them, I'll toss them.

labeled 2020-2-A

Pack 2 - Compaq Series PPB003C

It says, "Cell origin: Canada". That is a new one on me, and Compaq went out of business quite some time ago, so this ought to be interesting (in truth, I shouldn't even have purchased this pack).

Inside are 8 cells, ICR-18650G. All measure 0.1 volts and are discarded. Yep, should not have bothered pulling this fossil out of the bin.

Pack 3 - HP HSTNN-IB34

Inside are 8 green Sony SE US18650GR (G5) that all measure 1.4 volts and are discarded. There was no way to tell visually that this was any different from the following apparently identical pack (which should be no surprise to anyone).

labeled 2020-2-AA

I changed my mind -- pulling these out of the junk bin and charging them.
They charged and calibrated nicely to 2200 mAh. It is curious that these give higher capacity than the next pack which had "nicer" measurements initially.

Pack 4 - HP HSTNN-IB34

Another pack just like the above, with 8 green Sony SE US18650GR (G5) cells. These are good! In a 2x4 array and measure 3.2 2.9 2.9 and 2.8 volts.

They charged up nicely and test at 1500 mAh. These were originally rated 2200 mAh, so 1500 is OK for used cells.

labeled 2020-2-B

Pack 5 - Toshiba PA3819U-1BRS

Inside were 12 cells in a 3x4 configuration. They measured 1.3, 3.2, and 2.0 volts, so the outside 8 were discarded. I am keeping the central "quad" as a unit for some project where that might be handy. At 3.2 volts though, it is fully discharged and I should do something to bring it up to at least half charge soon.

The cells are Sanyo UR18650A R1112, rated at 2100 mAh.

labeled 2020-2-C

Pack 6 - Dell MN151

Inside are 9 cells, all Panasonic CGR18650E, and all measure 3.7 volts so this should be a great pack, all should be useful.

These cells are rated at 2550 mAh.

These are getting hot (140F) as they near full charge. Just like the same brand cells from Pack 1.

labeled 2020-2-D

Pack 7 - Dell NHXVW

Inside are 9 cells, LGABD11865. They measure 2.0, 2.3, 2.3 volts, so really should get discarded. I keep the six that measure 2.3 and they charge up nicely. I was initially going to discard the three that measure 2.0 volts, but see below.

These are rated at 3000 mAh, but only if charged to 4.35 volts, which I won't bother to do.

They calibrate to 2400 mAh, and charge nicely without getting hot, so it definitely paid off to keep them!

Playing fast and loose, I pulled the cells that measured 2.0 out of my scrap bin and put them on a charger. In less than a minute they are up to 2.7 volts, and in a few minutes they are up to 3.6 volts. I use my XTAR VP2 to bring them up to 3.6 or so, at which point I put them into a power bank and finish charging them in an ammo can. If they blow up and/or catch fire I don't mind losing the power bank and the ammo can should contain any disaster.

These end up charging nicely without issue and calibrate to 2400 mAh like their brethren.

labeled 2020-2-E (with black ring)

Pack 8 - HP HSTNN-LB31

Inside are 6 cells, LGCP218650. They measure 2.73, 2.46, 1.9 I discard the two that measure 1.9

These are rated at 2500 mAh at the usual 4.2 volts. They charge up OK, but only yield 500 mAh, so this battery was simply all used up.

I had second thoughts and pulled the two that measured 1.9, marking them with two black bands. They also yield 500 and 600 mAh respectively

labeled 2020-2-F

Pack 9 - Toshiba PA3479U-1BRS

This was an odd pack. It looked like it would hold 9 cells, but inside were tubular spacers in lieu of 3 of the cells. Also there was a "thermal fuse" in series with the cells, something I have never seen before (along with a thermistor). Thus there are 6 cells. Red Sanyo UR18650Y.

They measure 2.4, 2.4, and 1.5. I discard the two at 1.5 and give the other 4 black rings.

They actually seem to be charging up OK, not getting hot, and calibrate at 1600 mAh.

labeled 2020-2-G (with black ring)

Pack 10 - Dell 4M529

I am starting to think that if and when I buy more rejected laptop packs I am going to only buy Dell (maybe also HP). If nothing else Dell laptops are likely to be recent vintage. But the main thing is that my track record is pretty good with the Dell packs I have disassembled.

This one is a Dell 4M529. Inside are 9 Samsung ICR18650-28Q and they all measure 3.55 volts, which is just great! These are 2800 mAh rated and capable of being charged to 4.3 volts (so I will charge them to 4.2 and sacrifice some capacity).

labeled 2020-2-H

Pack 11 - HP HSTNN-DB04

Inside are 12 cells. They measure 2.9, 2.3, 1.6, and 1.2. The six that measure under 2.0 volts are discarded.

These are pink (flesh colored) LGDS218650. Made by LG, rated at 2200 mAh. Mine calibrate to 1900 or 2000, so these are in good shape.

I have second thoughts, retrieve the cells measuring 1.6 and mark them with two rings and try charging them.

labeled 2020-2-I

Pack 12 - HP HSTNN-DB32

Inside are 12 cells. Red KDOFJ25 -- Unknown manufacturer They measure 1.7, 1.7, and 1.9. I discard all of them.

Pack 13 - HP HSTNN-DB13

Inside are 6 green cells. Sony US18650GR G5, rated 2200 mAh. They measure 1.8, 2.2, and 0.9. Only the two measuring 2.2 were saved.

labeled 2020-2-J

The two that measure 2.2 volts charge and calibrate to 1900 mAh.

I mark the two that measure 1.8 volts with two black rings. They seem to charge up and behave fine. Now I am marking the 0.9 pair with 3 black rings.

Pack 14 - Panasonic CF-VZSU46

What a mess! The first time I have ever encountered this! The cells are glued inside the case with some nasty tenacious clue, and prying the cells out rips the cover off of half of the cells. The "best" cells measure 2.4 volts. I decide to discard the whole mess, and do it with pleasure.

The cells are grey NCR18650 rated at 2900 mAh.

Pack 15 - HP SX09 Notebook battery

Inside are 9 blue Samsung ICR18650-30A cells. These are 3000 mAh cells that will charge to 4.3 volts.

They all measure 1.3 volts, so they should be discarded. However, I decide to play fast and loose and see about charging these up. My Xtar VP2 will have nothing to do with them, but my Xtar "dragon" is happy to charge them, and in a minute or two they are up to 3.5 volts.

The first 4 charged nicely and calibrated to 2500 mAh.

labeled 2020-2-K

Pack 16 - HP EV06 Notebook battery

Inside are 6 blue LG cells: LGDAS31865, rated at 2200 mAh.

They all measure 1.2 volts. Uniformity is encouraging.

They charge nicely and calibrate to 2300 mAh. I do mark them with two black rings since they started at 1.2.

labeled 2020-2-L

Pack 17 - Dell type VV0NF

Inside are 6 blue Samsung cells. ICR18650-30B These are rated at 2950 mAh and can be charged to 4.35 volts. They all measure close to 2.5 volts.

These charged nicely to 2400 mAh.

labeled 2020-2-M

Pack 18 - Dell type VV0NF

The outside looked just like the pack above, but the cells are lime green. Nonetheless there are 6 lime green Samsung cells. Marked with ICR18650-30B juse like the pack above. These are rated at 2950 mAh and can be charged to 4.35 volts. These all measure 3.7 volts, so this pack is a winner.

They calibrate to 1800 or 1900 mAh.

labeled 2020-2-N

At it again!

I have 7 packs laying around. Months are going by and I realize that cells could be self discharging and "self-destructing", so it would behoove me to tear them apart and get what cells I can while I still can. So I am back at it 6 months later in August of 2020. It is typically 110F in my workshop in August, which is hardly ideal for charging questionable Li-ion cells.

Pack 19 - Dell type T114C

Inside are 6 red cells MK9M4C9, almost certainly Sanyo.
I measure 0.98, 1.49, 3.75 volts for the 3 pairs of cells.
I discard the 0.98 and put bands on the 1.49. The 1.49 start charging in the Dragon. It thinks they are Ni-MH at first, but after pumping some current into them, decides they are Li-ion after all.

One of the 1.49 cells got very hot when charging (137F). This was being charged in my 110F workshop. Later I put it back on the charger in my 78 degree office and although it didn't get hot, it calibrated with the charge and discharge very different (1200/1550). I tossed it. Then charging in my cool office I had another go to 147F, too hot to hold on to. I quickly removed and discarded it. Both of these were the cells that had measured 3.75 volts.

The two surviving cells charged and calibrated to 2200 mAh without incident. Curiously, these were two two cells that measure 1.49 volts! So I am left with 2 cells from this pack which is sort of distrust.

labeled 2020-8-A

Pack 20 - Dell type RFJMW "Extended"

Inside are 6 blue cells: ICR18650-30B Samsung. These are rated at 2950 mAh and can be charged to 4.35 volts. All six measure 3.78 volts. Very nice.
They charge up without issue and calibrate to 2000 mAh.

labeled 2020-8-B

Pack 21 - Dell type T54FJ

Inside are 6 salmon colored cells: LGABC21865 LG. These are 2800 mAh rated with a 4.3 volt maximum. All six measure 3.96 volts. Also very nice.
They calibrate to 1100 to 1500 mAh

labeled 2020-8-C

Pack 22 - Dell type U5209

The label says the cells come from Japan. Inside are 9 salmon colored cells: Sanyo R1122 015B (markings almost invisible). These should be ordinary 2500 mAh cells. They measure 2.67, 2.83, and 2.94
They charge and calibrate to 2100 mAh

labeled 2020-8-D

Pack 23 - Dell type Y0956

Inside are 9 green cells: Sony US18650GR G7 These are standard 2400 mAh cells. They measure 1.83, 1.95, and 2.26

labeled 2020-8-E

Pack 24 - Dell type FK890

Inside are 9 purple/pink cells: Samsung ICR18650-26C These are standard 2600 mAh cells. They all measure 3.2 volts They all charge nicely to 2200 mAh, which is pretty amazing.

labeled 2020-8-F

Pack 25 - Dell type M5Y0X

The last pack !!

Inside are 9 blue cells: Samsung ICR18650-30B These are 2950 mAh cells, with 4.35 volt maximum They measure all measure 3.8 volts
They charge nicely to 1700 or 1800 mAh.

labeled 2020-8-G

Charging in Tucson Heat

Right now my workshop is 110F (43C). It is August in Tucson, Arizona. Some recommendations are to charge only at temperatures less than 40 or 45C. Clearly I am at the upper range for these recommendations, and when working with questionable cells, this is all the more dubious. So I have moved my charging operations inside where the air conditioning maintains a temperature of 77F (25C). If nothing else, this makes it easier to recognize when a cell is getting overly hot while charging. When it does happen, it seems to happen at the end of the charge cycle.

And you will note that one of the cells from pack 19 was getting into trouble when being charged in this hot environment, but did fine when charged in a cooler room.

Have any comments? Questions? Drop me a line!

Tom's electronics pages / tom@mmto.org