So a friend gave me a battery pack from an old laptop he had. I am not sure what brand it was, I think an HP product. I of course tore it apart and it had 8x samsung icr18650-28a, lavender colored wraps.
So far I have taken 4 of the 8 batteries and charged them, and then did a discharge test at 300 mA on my AccuPower IQ338 and if I am interpreting it correctly all 4 of the ones I tested came in at about 2000 mAh. The spec of these batteries is 2800 mAh though.
I am not a big testing enthusiast or anything, I am just curious and wanted to find out if these batteries are OK or not, and to see if I am interpreting the results correctly. Are these batteries OK but maybe just a little tired? Or is this difference expected due to some sort of inefficiency involved in discharge testing?
At 300mah that’s pretty low discharge current for a capacity test. I usually discharge laptop pulls at 500mah. If you’re getting 2000mah out of 2300 that’s not bad depending on how old they are. The real test is if they’re any good is guilty charge them, let them sit for a few days and see how much they’ve discharged.
For a 6hr discharge rate, that’s a pretty ‘tired’ capacity to achieve. Of course this is also just part of the story. The internal resistance is likely very high and voltage under load would likely be very poor for anything even approaching 1C (2Amps in this case). They still could live a second life in the right application, but for flashlights, I personally wouldn’t waste too much time with them, especially if you have a good recycler near you. It’s really up to you though.
@sirstinky, i made a typo, they are rated 2800 mAh, not 2300. So I’m only getting 2/3 capacity. jaredm i bet is right, these are probably end of life.
@jaredm, lol i suppose i am just trying to be a cheapskate. i have no idea how old these cells are, in fact my friend said he had set the battery pack aside for me nearly year ago and had just forgotten to give it to me until now. on the plus side, i don’t have any super high end flashlights. I’d be using them in my edc light which is a pretty unremarkable convoy s2+, and i also would want to use them in my vape, a battlestar mini that i run at very modest 14w for my mtl tank.
Even for low drain e-cigs, I would say no to that application. These are not a ‘safe’ chemistry to start with and second life usage brings a whole other host of unknowns into the mix. 14W is about twice of what I’d recommend to pull from these. They’ll do it I’m sure, but not worth the risk IMO.
HKJ tested these cells many years ago. Results here
As for the S2+, what amperage driver is installed? Emitter?
Like Sirstinky said, charge these up, let them sit (I’d say 4-7days) and then measure their voltage. If any are below 4.0V they are trash. 4.00-4.10 = not-so-hot and if they hold above 4.10 then they should be okay for a while at least.
