I have 2 pairs of 18650 batteries...one of each pair now takes FOREVER to charge. why?

[supermarket]

Is this normal? Does this mean the battery is near the end of its life cycle?

Originally I thought my charger was failing.....so I bought a new one. It appears it wasn't the charger , because I'm trying out the new NiteCore charger I bought today, and the same thing is happening with the first pair of batteries I'm trying on it.

I put the batteries in at the same time, and the first battery finished charging somewhere around 3 1/2 hours. The second battery is still charging at 4 1/2 hours, SLOWLY creeping from 4.14 volts to 4.17 volts in the past HOUR.

Both pairs of batteries are about 1 1/2 to 2 years old, and charge about 3-4 times a week.


Has this happened to anyone else?

 

[supermarket]

On second thought, the second battery just finished charging. It might *not* be the batteries, it might be the fact that since I tried charging the batteries in the suspected faulty charger, only one battery actually was charging, while the other wasnt.

I'll know for sure when the batteries I'm using now run low, and I have to charge them in the new charger.

 

[State O' Flux]

Assuming identical cell quality...

If you're installing these batteries in dual cell mods, and for some unknown reason the chance of each battery going into the same sled side is better than 50/50, and... (always more "ands") one side of the cell sled has substantially better conductivity than the other (producing an uneven discharge rate)... I can see how one cell would require more time to charge.

 

[edyle]

Both pairs of batteries are about 1 1/2 to 2 years old, and charge about 3-4 times a week.


Has this happened to anyone else?

3.5(charges) x 4(weeks) x 21(months) = 294 recharges.

Nominal life cycle is 300 recharges

Looks to me like your batts are getting old and cranky

 

[Mooch]

Both pairs of batteries are about 1 1/2 to 2 years old, and charge about 3-4 times a week.

Depending on how hard they were used, those two batteries could be nearing the end of their life. Might be time to replace all four.

[edit] Oops...too slow. @edyle types faster than I do.