Rechargeable 18650 shelf life

nightowl66

Newly Enlightened
Joined
Apr 7, 2009
Messages
73
Location
NW Ohio
I bought 2 rechargeable 18650's, my light takes one. Is it a good idea to fully charge the spare and let it set?
 

Rosoku Chikara

Enlightened
Joined
Dec 28, 2012
Messages
606
Location
Niigata, Japan
I should probably let someone else who knows more about Li-Ion answer this, but I think it depends on how long you intend to "let it set." Others who really understand the Li-Ion chemistry can give you a better answer, and you can also probably find the answer by searching the forum, but as I understand it, you do not want to store a Li-Ion cell for long periods of time at full charge. (In other words, the cell will "last longer" in storage, with something less than a full charge.) However, I think that this is only important when you are planning to store it for months, or perhaps even years.

Under normal circumstances, I think you would want to keep one fully charged as a "spare." And, put that "spare" in your flashlight when the first cell begins to lose its full performance. In other words, I think you would want to use both cells, but interchange them each time you recharge.

(By the way, do you have a volt meter? If you don't, you will need to get one, if you are going to use Li-Ion rechargeables such as 18650s.)
 
Last edited:

hellokitty[hk]

Enlightened
Joined
Jan 29, 2007
Messages
645
It's best to store them at around 40% charge, but anything lower than 90% charge will significantly slow down the degradation rate.
So if I am not planning on using my other battery anytime soon, I charge it to 4.1 or a little lower and leave it lying around. It's not a big capacity hit but is ready to go when needed.
 
Last edited:

kosPap

Flashlight Enthusiast
Joined
Mar 1, 2007
Messages
2,896
Location
Naoussa Greece
I say use the hell out of them...they will go down in 3 yaers abyway.

I measured the internal resistance of soem 2 year old battreies that were resting in a flashlight with onyl a few partial charges
they clocked around 0.24 ohm while the new ones clock 0.13. One more year and they will be considered OLD
 
Top