Keep or toss these cells? (16340 ~ 2.4-2.7V)

Hi there, this thread just motivated me to check all the flashlights in my collection to make sure there were no e-switch vampire drained cells… and unfortunately I found some. Strangely, at least one was in a twisty flashlight that I’m positive I had left disconnected, not sure what happened there. I found one non-protected 14500 at 0.00V (!) so that one’s definitely a goner. But I also found three 16350 cells that I assume are all protected, because they were registering 0.00V until I put them for just a second on the charger and they immediately jumped to 2.40, 2.60, and 2.71 volts respectively. The 2.60V one later went back down to 0.00 after about a half hour, which I assume is the protection circuit kicking in again? At any rate, what do you think about keeping these cells? If at all possible I’d like to keep them, because quality Li-Ion cells are nearly impossible to obtain right now where I live, but obviously I don’t want an explosion either. Thanks for the help!

Charge them at low rate then check internal IR if you have a charger that can test that.

Have lots of laptop pulls that where near 2.6-3.2 and all but one came back no problem.

What I do when not sure id charge them full then store them somewhere that they can do no damage if they vent. Let them sit a few days and recheck voltage.
If they drop a lot, ditch them. If only off by .05-.1 probably OK.

Cycle them and see what run time you get.
If they appear to charge up really quick they are probably toast.

One other thing, for whatever reason a lot of 16340’s do not seem to want to top off at 4.2, seem to stop at 4.15-4.17 and just sit there.
The 16340 Battery format in general kinda sucks, much prefer 18350 cells but still have some 16340 lights that I like so it is what it is.

HTH
Keith

Just recently I had a coupla stored 18350s kinda drained to nothing that after charging came back just fine. Stuck both in a shorty SC31pro, and both go full blast no problem, and hold a charge nicely.

Ran a few cycles through my Ope, and they both had near full capacity, too.

Fantastic, thanks a lot for the suggestions! And what would be an acceptable range for the IR?

Interesting… Like drained to 0.00V ? Protected or unprotected?

You should be able to see the protection circuit on the batteries if they are protected batteries. And they should be safe it you charge them and they charge normally and retain a 4.1-4.2 volts. But if they get too hot or cannot hold the voltage, I would recycle them.

Thanks! Looks like they have the protection circuit? The one with the USB charge slot obviously does, and the Trustfire says it’s protected in small letters. The “Blackwater” one is what I’m not sure about, but it’s the exact same length so it must be protected too.

Ach… ya gonna make me look?

Yeah, protected. They’re those “DE” / “Digital Energy” cells Rat Shack was selling off when discontinued. Shouldda bought way more, those 18350s and more 26650s, as they’re pretty decent. Rated 800mAH on the wrap, the Ope (not known for being overly optimistic) had them clocking in at about 900mAH.

Stuck ’em in the Ope when my light didn’t light, at all. Didn’t even start charging. Stuck ’em into my LK and it started charging right up. Once it got going, back into the Ope and it was already a decent voltage (whatever it was, forgot).

From there, it was like they weren’t the slightest bit perturbed.

Same like a bunch of laptop pulls, ancient panny-As, not even -Bs. 1 pair was completely dead, but 2 other pairs survived just fine. Still got ’em in low-stress lights, working fine.

They are fine you just tripped the protection circuit which should cut in around 2.8-3v. They all look like they are protected cells and once you put them back on the charger it reset the protection circuit.

I am not going to condone the activity but i use cells that have gotten to as low 2v or under. Its not good for the cell and will effect its number of recharge cycles but they should be okay. From what i have read internal cell damage should only occur with negative voltages. When saying this anything under about 2.5v is basically/ near enough to 0v as there is no capacity left at a certain point.

As always just test the internal resistance feel if the cell is getting to hot and also monitor when the max voltage the cell will retain.

Thanks to everyone for their comments! How do these IR values look? (For some reason the Opus charger consistently refuses to give a value for the Trustfire in all the slots.)

Protection circuits can alter readings it seems.

The Green one looks too high for my liking.
Others probably acceptable.

Do this, run discharge test at 500 mAh on all three. If that green one comes down real quick as is suspected, chuck it.

Small cells always have higher internal resistance compared to bigger cells in general, the protection circuit adds even more resistance. The green cell has heaps high resistance but its probably a low drain cell but keep an eye on it.

I had a similar Soshine 16340 that was dead. I would charge it okay but it would go flat after a few days without use.

OK, thanks again to everyone for the tips! Here’s what I’m getting:

Zanflare charger after fast test, I believe this is the capacity it measured for each cell? (All displays showing mAh)

And the IR according to Zanflare, it can’t measure the green one:

And the IR according to the Opus, it can’t measure the Trustfire:

After a few days they appear to be holding their charge! I did several discharge/charge cycles on all of them, and as you can see the IR on the green one came down to a reasonable level now. So overall a success story. (The red 14500 is definitely done for, as expected.) Thanks to everyone for the tips!

The Efest cell won’t be protected, It should be a high drain cell? Is it IMR chemistry? It should have low internal resistance.

Try and keep the 16340s in good nick its getting harder to find the smaller sizes with protection circuits.

I’m not entirely sure if it’s IMR, but it’s definitely not protected, which is why it was truly sitting at 0.00V for quite a long time thanks to a vampire e-switch. When I first put it on the the charger for a few seconds the voltage only went up to ~0.02V, unlike the other protected cells that went from 0.00 to >=2.4V after a few seconds because the charger reset the the protection circuit. The IR indeed wasn’t too high and it never got hot, but after quite a few refresh cycles it would still charge way too fast up to ~4.1V and then within an hour fall below 3.0V. So I already tossed it.

Yeah, I learned a less from this one. I used to store most small lights in their lying down position, but now I’m standing up the ones that have a battery inserted so I remember to check the voltage regularly.