Li-ion cell charging normal?

[fivemega]

Li-ion cell charging normal?

Hi folks,
I have numbers of new Li-ion 18650 and using my old Nokia cell phone to recharge them one at a time. All were charging normal except two of them which is charging and battery indicator scroling up (indicates charging) but never stop (which should after fully charged) no matter how long is being charged. I measured over 4.1 volt after removing from charger. This is almost same voltage of good batteries. Do you thing these two cells are bad?
BTW, are there any Li-ion single cells other than 18650, 14500, prismatic 093447 and Pila ?
Thanks

 

[CM]

Re: Li-ion cell charging normal?

Have you tried loading it down to see if it can drive a reasonably heavy load? If not, then I'd say it's toast. I have a few dead cells that measure around 3.8V but cannot drive anything, not even 5mm LED's. The true test is a good load on the order of 0.5C to 1C.

There are many single cells available, too numerous to list here. The most common sizes are 18650 ( currently the workhorse of them all), 18500, 17670, 17500, and numerous prismatic cells of various shapes and sizes.

 

[fivemega]

Re: Li-ion cell charging normal?

Thanks for reply CM
These 2 batteries can handle up to 1 Amp with no problem but act strange under charge.

 

[CM]

Re: Li-ion cell charging normal?

Sounds like they're still good then. I'd probably mark those as being "questionable" since they should signal to the charger that they're full. Another test you can do is to see how well they retain charge over some period of time like a week or so. Take one of the "questionable" ones and one known good one after you get them off the charger and let them sit. Measure the voltage after a week or so and see if the "questionable" one has the same open circuit voltage. If it's significantly lower than the "good" one, then it's probably towards its end of life. Give us a report after a week or two. Or should I say, take two aspirins and call me in the morning /ubbthreads/images/graemlins/grin.gif