I found a TNL-ITR18650-2200 3.7v battery in one of my old tool boxes with a date stamp of 12.12.05
IIRC, it was inside a rechargeable device I disassembled that had broken. I forget exactly what it was in.
I’m amazed that at 12 years old it still has a discharge test capacity of 2100mAh
How can that be?
I watched an utube video on extending the cycle count on li-ion cells, there is supposedly at least 7 different chemicals that can be added to the basic li-ion mix, and what ones are used can make the difference between 200 cycles to 2000 cycles and these recipients are closely guarded secrets.
They help to reduce damage from excess heat while charging/discharging or slow down the process where the anode/cathode gets blocked over time reducing the capacity.
I have some bluetooth headphones with li-ion built in that i have had for years and they still last a long time on a single charge.
John.
Recently i disassemble battery of old samsung laptop (bought in 2004) and got 6x 18650 cells 2200Mah.
Measured capacity is between 1930 - 1990 mah, near 87-90% of initial capacity
Right?
Now I cringe when I think of all the laptop batteries I tossed with broken laptops : - (
I used ZB206+ v1.3 Battery Tester from Fasttech
What is its internal resistance?
I haven’t 4-wire holder, to measure resistance.
Good question. I’ll check as soon as my hobby charger is available
There are plenty of appropriate ways to use them, as power outage back up cells for an SRK is one that comes to mind. That higher internal resistance can show benefits in terms of shelf storage. Just keep them in a safe place. I wouldn’t store new cells fully charged but don’t feel as protective of older cells, just concern over the higher risks they come with.
I don’t have a fancy charger or anything to test capacity but I’ve pulled cells out of old laptop battery packs that were still near 4.2v after sitting in a basement for 12 years and they probably sat for a few years before they made it to the basement. Many of the cells that old will be throw-aways but it amazes me that there are still good cells in those really old packs. The old Dell packs in particular have given me plenty of usable 18650s.
Measured with my Turnigy Accucell 6 the IR = 137milliohms
That makes sense. So what you’re saying is that while I measured 2000 mAh capacity, it will only deliver that at low discharge rates?
In fact, the discharge rate that I used WAS very low…like 300 milliamps.
So this battery would be good for something with a very low drain (say, under 500mA) but nothing high drain say over 500mA?
Again, that makes perfect sense to me.
I don’t know what new batteries are but my 4 year old UR18650FM are about 50 milliohms on my Dragon VP4
This same battery showed a significantly lower IR on my other hobby charger.
Seems to me you have to do the “real” IR test to get an idea of the real IR
Chargers don’t seem to be accurate on that measurement imo
not only inaccurate but repeatability is poor.
i use a dick smith esr to test.
its meant for capacitors but is fine for batteries if you didnt install the protection diodes to protect it against charged caps.
Have some dell pack and even older batteries that still do over 2000mah and have ok IR. Both panasonics and LGs. Using them for years now too.
I have: AnaTek, Blue ESR/Low Ohms Meter, 0.01 Ohm to 99 Ohm for >1uF Electrolytics – Alltronics LLC but I don’t think it can measure cells. Lii-500 gives good enough readings for pass/fail.
thats the new version.
mine is from 15 years back and was a kit.
and it does fine testing ir/esr of batteries.
in fact it tests exactly the way most li-ion mfr’s do.
Well,
I tested this 12 year old battery again today and put it against a discharge current of 500mA and it had 2028mAh capacity (rated at 2200mAh) so this 18650 dated Dec 12, 2005 still has 92% of it’s original claimed capacity and is that is at least under a 500mA load. Not bad 
I will probably test it under a 1A load next just to see.
Do you think you could get 12 years out of any 18650 you purchase today?