Author Topic: 18650 Li-Ion Low self discharge?  (Read 632 times)

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Offline Maln12

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18650 Li-Ion Low self discharge?
« on: February 22, 2017, 08:08:24 AM »
I've read that in general Li-Ion like 18650 retains it's charge for quite a few months. But all the 18650 batteries I look at don't seem to mention a low discharge rate of any kind. For me any kind of laptop or phone battery just drains soo quickly when the appliance is off that going to use it even a few weeks later the battery is flat. I'm not sure how typical appliance Li-Ion's compare to Flashlight 18650 Li-Ions?

What 18650 batteries would hold much of there charge for 6months to up to a year in a LED stored away?


Offline robo819

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Re: 18650 Li-Ion Low self discharge?
« Reply #1 on: February 23, 2017, 10:33:27 AM »
Most of the 18650 cells when just sitting on a shelf or what not . retain their charge for a long time. I have some that have been sitting at 3,6 to 3.7 volts for close to a year and I check all my extra cells about every 3 months. So far the ones that haven't been touched are still at the storage voltage after all this time , some protected cells and some unprotected.

NOTE: If putting the Lithium cells in storage for prolonged periods it is recommended for most of them that the storage voltage is at or around 3.6/3.7 volts. Also a cool or cold place in the dark is said to help preserve the life of the cells.

Stay away from 99% of anything with ****fire in the name , other than Thorfire as they usually have decent products.
Stick with the  good known brand names like Panasonic , Sony , Sanyo and Samsung and always try to research or ask before you buy from just anyone , to be sure you get the cells from a reputable dealer so you don't end up with fakes or junk cells.
« Last Edit: February 23, 2017, 10:42:34 AM by robo819 »

Offline JohnnyMac

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Re: 18650 Li-Ion Low self discharge?
« Reply #2 on: March 01, 2017, 01:55:14 AM »
What Robo said.
« Last Edit: March 01, 2017, 01:55:37 AM by JohnnyMac »

Offline Maln12

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Re: 18650 Li-Ion Low self discharge?
« Reply #3 on: March 29, 2017, 08:24:48 AM »
Doing some reading, it seems Lion loses 1-3% capacity per month at 20degress C, plus 1-3 % more from the internal protection.

This would mean to me that storing them at around 50% SoC which is what is usually advised leaves them near 20% SoC after just 3months.

So if you need to use your light 3 months later its probably not going to give much runtime, however storing them fully charged is usually not advised either as the cells spend much of their time in a high SoC & their life will get shortened.

That's my understanding.