February 15, 2017

My harvested loptop batteries - late 2017

I tried something new. I looked up some eWaste places near where I live and paid one of them a visit. They had a huge box of what must have been several thousand laptop batteries. I was told I could have all I wanted at 5 dollars per pound. I grabbed a bunch, taking care to select name brand packs and to avoid generics. This turned out to be 15 batteries, 11 pounds and I paid $55 for them. This works out to $3.67 per battery.

All told this yielded 108 cells. 30 of these were immediately discarded. The yield then is 78 usable cells, so a 72 percent "yield". This will end up getting reduced a bit as these get tested. The average price per cell is thus $0.71 per usable cell.

My initial quick estimate was 100 cells and a 50 percent yield, and a predicted price per cell of about $1.00

Note that this harvest yielded a lot of green Sony US18650GR cells. These come in different grades (as I learned later). Those marked G5 are 2200 mAh cells, and most of what I got were these. I did get some marked G7 which are 2400 mAh. If I ever run into G8 marked cells, these are 2600 mAh. All of these are rated for at least 4 amps.

I am also taking care to fully or partially charge any of these cells that are fully discharged -- any that measure below 3.6 volts. The idea is that these fully discharged cells can self discharge into the unsafe region if I leave them sitting around. Someday I hope to have a charger that can be configured to automatically charge batteries to 3.8 volts (the recommendation for storage).

Pack 1 - Dell 1691P

Marked 14.8 volts, 3600 mAh, 3A charge current.
Inside are 6 Orange Panasonic CGR18650HG cells. All the cells measure 1 volt or less so all are discarded.

A dismal start, I wonder if I wasted my money?

Pack 2 - Sony VAIO PCGA-BP2EA

Marked PCGA-BP2EA 11.1 volt 4000 maH
I mark these 2017-11-B

Inside are 6 Panasonic CGR18650CC cells. These are 2150 mAh cells. All measure 3.4 volts, so they look good.

Pack 3 - Dell type 66Whr

Rated 14.8 volts 4460 mAh.
I mark these 2017-11-C

Inside are 8 green Sony US18650GR cells. Four measure 2.9 volts and four measure 3.3 volts.

Pack 4 - HP HSTNN-IB34

This is a long pack, a bear to open up -- entirely glued together. Two thermistors -- looks like a quality item.
I mark these 2017-11-D

Inside are 8 green Sony SE US18650GR cells. Two measure 1.9 volts and are discarded. Two measure 2.6 volts -- these get a dot Four measure 3.4 volts.

Pack 5 - Dell type J1KND

Rating 11.1 Volts, Capacity 48Wh
I mark these 2017-11-E

Inside are 6 blue LG LGDAS31865 cells. These are 2600 mAh cells. They all measure 3.48 volts, looks great.

Pack 6 - Dell type PC64

Rating 11.1 Volts, Capacity 56Wh
I mark these 2017-11-F

Inside are 6 purple/pink Samsung ICR18650-26C cells. These are 2600 mAh cells. Two measure 1.90 and are discarded. Two measure 2.36 and are kept with two black rings. XXX Two measure 2.60 and are kept.

Pack 7 - Dell type GK479

Rating 11.1 Volts, Capacity 56Wh
I mark these 2017-11-G

Inside are 6 purple/pink Samsung ICR18650-26C cells. These are 2600 mAh cells. All measure 3.75 volts, looks very good.

Pack 8 - Acer model BTP-AQJ1

Rating 11.1 Volts, Capacity 4400mAh

Inside are 6 green Sony US18650GR cells All measure under 2.0 volts and are discarded.

Pack 9 - Acer model BTP-AQJ1

Rating 11.1 Volts, Capacity 4400mAh

Inside are 6 green Sony US18650GR cells All measure 2.8 volts.
I mark these 2017-11-H

Pack 10 - Dell model BAT3151L8

Rating 14.8 Volts, 3900 mAh

Inside are 8 lime green Panasonic CGR18650A cells. Four cells are under 2.0 volts and are discarded. Two cells are 3.09 Two cells are 3.20
I mark these 2017-11-J

Pack 11 - Dell type 66Whr

Rating 14.8V 4800 mAh

Inside are 8 green Sony US18650GR cells Six measure 2.8 volts, two measure 2.7 volts.
I mark these 2017-11-K

Pack 12 - Toshiba PA3399J-1BRS

Labelled 10.8 volt, 4300 mAh

Inside are 6 red cells, not clearly labelled, probably Sanyo. All measure less than 2.0 volts and will be discarded.

Pack 13 - Dell T54FJ

Labelled 11.1 volt, 5100 mAh, "cell made in Japan"

Inside are 3 orange cells PAJZ4D All measure 4.04 volts, these should be fine.
I mark these 2017-11-L

Pack 14 - HP HSTNN-IB31

10.8 volts, 43Wh

Inside are 6 blue Samsung cells, ICR18650-20C. Four measure 2.3 volts and are given two black rings. XXX Two measure 3.6 volts.
I mark these 2017-11-M

Pack 15 - HP HSTNN-IB17

10.8 volts, 43Wh

Inside are 6 blue/green Panasonic cells, CGR18650AF. They all measure 2.9 volts
I mark these 2017-11-N

Have any comments? Questions? Drop me a line!

Tom's electronics pages / tom@mmto.org