When do you dispose of a 18650 that has dropped in mAh?

[Buzzing_Bulb]

Hey,

So yeah I’m busy with discharging my harvested 18650’s with some capacity testers.

Some batteries that were 2200mAh when created are now pretty low in mAh’s.

I was wondering at what level of % drop are they supposed to be disposed of?

I’m gonna keep the ones that read above 1000mAh but what about the lower ones?

I guess I can use them for simple low power tasks like night lights.

Any info on that?

Edit: also can they become dangerous?

[Wrathbringer27]

When its getting into negative mAh and starts creating a black hole and destroys everything.

[everydaysurvivalgear]

What voltage are the batteries charging to max?

[dw911]

@Wrathbringer27

When its getting into negative mAh and starts creating a black hole and destroys everything.

Lol

As they get older I use then in low powered lights or in power banks.
I keep a check on them when charging and find they tend to get hot even at say 500 mah charge rate, when they have reached the end of there life - although they still charge and work fine - I recycle them from a point of veiw of safety

[dw911]

@Wrathbringer27

When its getting into negative mAh and starts creating a black hole and destroys everything.

Lol

As they get older I use then in low powered lights or in power banks.
I keep a check on them when charging and find they tend to get hot even at say 500 mah charge rate, when they have reached the end of there life - although they still charge and work fine - I recycle them from a point of veiw of safety

[hIKARInoob]

@gauss163

As you may know, the industry standard is to consider Li-ion cells end-of-life once their capacity drops to 70-80% of their initial capacity. One of the reasons for this is that at that stage the IR may have increased so much that the increased heat could possibly lead to thermal problems (possibly greatly increasing the chance of thermal runaway when they are used in devices with limited cooling capabilities).

So if you continue to use them beyond this point be sure to keep a close eye on thermal issues, both while charging, and while in use.

Interesting point. Perhaps HKJ can test some old cells to see how properties have changed, and the consequences in terms of safety.

[Lexel]

If you dont push em hard with DD or very high charge currents there should be no real danger of overheating

Just keep in mind that charge and discharge rates are based on the capacity, so lower capacity results in smaller currents