I don’t recall seeing any, but someone else may chime in.
High voltage cells tend to be focused on capacity, while tool packs tend to use cells optimized for discharge rate. For a given chemistry, cell designers trade discharge rate for capacity by changing the ratio between electrode material, and electrolyte. Moreover, different chemistries lend themselves to one application or another, and the cells used in tool packs tend to use a different chemistry than high capacity cells. I’m not sure, but the specific chemistry may also influence whether high-voltage is a viable technique for increasing capacity, but even if it is, it comes at the expense of durability.
Panasonic and now LG have lithium nickel cobalt aluminum oxide cells that deliver high capacity and moderate discharge rates (~10A) but I think they all have 4.2v charge termination.
I scored at the Best Buy today…16 different battery packs, including a few non-laptop packs, which have non-tamper screws on them. What type of tool do y’all use to remove them??? I’ll update this post as I tear them apart. Here is what I have:
1 x Roomba 14.4V Ni-MH
1 x Apple 10.8V Li-ion Polymer Mac Book Pro M/N A1281
1 x Duracell 6V Ni-MH DR10 camera battery
2 x Sony 7.2V Li-ion L Series Infolithium NP-F550 for Mavica HandyCam
2 x Ryobi 18V LI-ION drill battery P103
1 x Ryobi 18V LI-ION drill battery P107
1 x Craftsman 18V Ni-Cad drill battery 130260001(This one will probably go back in the bin)
1 x Toshiba 10.8V Li-ion battery pack PA3780U-1BRS
1 x Toshiba 10.8V Li-ion battery pack PA3534U-1BRS
1 x HP 10.8V Li-ion battery pack MU06 (593554-001 replacement no.)
1 x HP 10.8V Li-ion battery pack EV06 (474170-001 replacement no.)
1 x Dell 11.1V Li-ion battery pack Type J1KND
1 x Dell 11.1V Li-ion battery pack Type U4873
1 x Lenovo 10.8V Li-ion FRU P/N 45N1175 ASM P/N 45N1026
I expected something along the lines of Samsung 26F or so.
But inside were Sanyo UR18650FM N30B, stating so, embossed and as always barely readable, on the translucent red wrapper.
Never saw this translucent wrapper on a Sanyo cell before, but the ring on the plus side is light blue as usual. In addition I’m pretty sure the battery I opened is genuine Samsung. I have 2 NC10 which I had bought new at the time and their batteries are identical to this one, which I had sourced from eBay. Opening was difficult, to say the least. I had to crack the casing but the real pain was the glue-tape inside, which was sticking terribly to everything it was attached. I had to rewrap the cells as some of the wrapping did not survive the disassembly.
The cells were down to 2.4V - 2.6V. I carefully charged them, temperature was not rising. As they held 4.2V pretty good for a day, I made several cycles with low charge and discharge current. They sat for a week and went from 4.21V to 4.18V. That convinced me to use them.
Capacity is between 2200 and 2300 mAh. That’s pretty cool for cells this age (N30B means 2009, week 30). But that’s only for lower current. At 3A voltage sag seems to be higher than it usually already is with these LiCo cells.
I found this battery pack in the recycle bin yesterday. It seems to be for some sort of portable Hoover vacuum. It was strange to see the old-fashioned Hoover logo on a modern battery pack. It had to be modern, it says Lithiium Life”.
Checking the back of the pack, it claims “20.0V MAX and 72Wh”
The 20V max probably means that it contains 5 cells in series. Most tool packs would call this an 18V pack, although some companies would call it a 20V pack, for example DeWalt.
But a rating of 72Wh means that this pack is rated at 4Ah and multiplying that by the “standard” rating of 18V for this type of pack would give the 72Wh rating. Can’t wait to see what’s inside!
There is a sophisticated BMS board with controller chip and 2 FET’s. I presume 1 FET acts as a switch to shut the pack down when any cell reaches 4.2V during charging, and the other FET acts to switch the pack down when any cell discharges to less than around 2.75V.
Now to see what the cells are!
There they are, this pack contains 10 - Samsung 20Q (20R), 2Ah cells (2000 mAh)! All cells were sitting at around 2.4V when I measured them. First thing I did was trickle charge them all up to 3.0V, It only took a about 10 seconds (a good sign). Now I am in the process of individually charging them up with my OPUS. Each cell-pair (5S2P configuration) so far has soaked up 4000mAh of charge (another good sign). I will report the final results later
I think this pack was a VERY good find, as it likely will yield 10 good Samsung 2000mAh IMR’s
EDIT: May 7, 2015
Turns out this IS a very good find. All 10 cells discharge to over 2100mAh. Most likely the reason this pack was tossed in the first place was because the included BMS board was bad. Even though the cells are good, the pack could not output through the board.
Samsung IMR 20Q’s are rated at 2000mAh, all of these cells test out at slightly over that. So all 10 cells are in “like new” condition.
So is there a trick to getting to rummage around in a recycling bin for these batteries? I have been nearly run out of two Home Depots and Best Buy looked at me like I had a second head growing out of my neck… They even had a “why would you want to drink the toilet water?” look about them when I asked at that Best Buy to look through the recycle container for the batteries. I have been polite and extremely neutral when they say it is “for my safety” that they cannot let me do this, but what kind of techniques have worked for others here?
Do you know someone that works for a company that has an in-house IT department?
That's where I get mine, 40-50 packs per year. We have over 600 employees at my office and zero desktop computers. 70% of them bring them home each night or offsite to clients everyday so lots of wear on the batteries.
If you are in a high traffic area like a college you can make your own recycling box like they have at the home depots.
Or you could just steal a couple of those cardboard home depot recycling boxes....and recycle them by dropping off a new box (empty) and taking the old box (full) .
" What are you doing ?? "......
"just picking up the recycling ..here's your new box" .:P
if the push you just say green stuff like " Give a hoot ..Don't pollute " or .. quote Al Gore