when to replace rechargeables due to endurance...

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turkeydance's picture
Last seen: 5 hours 3 min ago
Joined: 02/20/2020 - 18:53
Posts: 1540
when to replace rechargeables due to endurance...

essentially; for you, what determines
the end-point of a rechargeable battery?

here are my details:
an 18650 is slowly dying.
it will hold a charge for continuous use
for around 30-40 minutes. after that,
the output dims the light significantly.

what is your ONE sign to decide to discard and buy a new one?
age? corrosion? yes, there can be multiple indicators….
i would like to know what is your one-and-done?

ChrisGarrett's picture
Last seen: 5 hours 13 min ago
Joined: 02/12/2014 - 22:03
Posts: 1122
Location: Miami, Florida

80% of original capacity is what the hacks in Vegas tell us.


BlueSwordM's picture
Last seen: 3 hours 31 min ago
Joined: 11/29/2017 - 12:34
Posts: 6381
Location: Canada

I pretty much never replace rechargeable cells, especially since I take care of them so well.

Anyway, I’d go for 70% of original capacity and significantly increased for IR to derate them and use them in other applications.

My very own high current Beryllium Copper springs Gen 3:
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

jon_slider's picture
Last seen: 3 hours 55 min ago
Joined: 09/08/2015 - 12:20
Posts: 6081
Location: Central North America

I have some old AAA eneloops and when new they gave
80 lumens, but now, 7 years later, they only achieve
35 lumens. Since I dont use high mode, Im happy to keep using them at the
15 lumen output level that the medium mode provides.

I did recently order new Eneloops.. I feel Rich in Lumens again

Last seen: 2 days 12 hours ago
Joined: 11/26/2020 - 11:43
Posts: 438
Location: USA

I’ve only been into this “hobby” for 18 months or so. I bet I only have one or two cells that have been cycled more than 4 or 5 times, and have probably a dozen cells that have never been used. I doubt I’ll ever see a situation of significant capacity loss due to high cycle counts. The only thing I would ever be concerned about is high internal resistance, but I’ve read conflicting schools of thought on what constitutes values high enough to warrant discontinuing use of a particular cell. The caveat here as well, is having an accurate method to measure/calculate IR. My Opus allegedly performs the function, but I don’t necessarily believe it to be more than a rudimentary guess as the values are so inconsistent.

wle's picture
Last seen: 2 days 11 hours ago
Joined: 01/07/2015 - 13:49
Posts: 2936
Location: atlanta ga

i don;t have a test

i throw them out if

a. they heat up when charging
b. they seem to never finish charging
c. the run time seems too short
d. i get better newer cells, and or start to get too many i am never using

"You never have the wind with you - it's either against you, or you're having a good day."
    Daniel Behrman, "The Man Who Loved Bicycles".
It never gets easy, you just go faster.   
-Greg Lemond.

Helios azimuth
Last seen: 1 hour 54 min ago
Joined: 04/08/2019 - 22:23
Posts: 372
Location: Sierra Nevada Mountains

wle wrote:
i don;t have a test

i throw them out if

a. they heat up when charging
b. they seem to never finish charging

Me too. The only batteries I have sent to the recycle bin have had charging issues or do not hold voltage.
Last seen: 1 day 35 min ago
Joined: 11/01/2018 - 16:14
Posts: 469

I found that one of the Sofirn 21700s I had was completely drained in a light I thought I’d locked out.

The battery charged up just fine and it even did fine in the capacity test…but after leaving it off the charger a while and checking on it, I noticed it was warmer than an identical cell sitting nearby. I measured the voltage and also noticed a significant drop, suggesting an internal short. Over the next few days it regressed back into a fully discharged state.

I don’t often toss Li-ion cells, but this was a clear sign that this cell was ready to retire. It’s currently waiting for recycling, as soon as I can visit a drop-off for them.