Two years ago I picked up some Klarus 16340 rechargeable batteries that were on sale for $2.95. I thought that was a good price. I did a capacity test with a similar Fenix battery and the capacity was pretty close to being the same as a Fenix 16340. So I was happy.
Today I opened up one of the brand new Klarus batteries in their sealed case (been sitting for 2 years unused) and the voltage was 0.0V. so I tested the rest of the batteries and they were also 0.0v. I know they were shipped around 3.65v but evidently just sitting unused (not even in a flashlight) that after 2 years they had discharged to the point of the protection circuit tripping. I have never had that happen with any of my other protected batteries. So it makes me wonder if Klarus circuit has a little higher internal parasitic drain than other brands?
They are all charging up just fine and immediately bounce to over 2.50v (around 2.68v) with a 250mA charge current. So I think the protection circuit just tripped and they are still good. But I have to say, I may not trust them as well as some of my others. I have migrated to the Vapcell T8 as of late. I guess I am going to be watching the voltage on them over the next few weeks/months…………just curious as to if they do have a higher internal discharge rate than my other 16340 batteries (mainly Fenix and the unprotected Vapcells). Anyone else seen this?
Some cells have higher self discharge than others. If there’s a protection circuit, it’s going to read 0V when it trips around 2.5V or 2.6V. The true cell voltage might still be above the danger zone. Do not charge liion batteries measuring below 2 volts. I’d recommend checking batteries in storage once per year and topping them off to ~3.7V as needed.
Good points. It just caught me off guard to see them all at 0v because they were not being used. But now that I’ve had time to think about it, I haven’t seen this issue before because all the rest of my cells are currently in flashlights that I periodically top off. The only other spare cells I have are Vapcell T8’s and they don’t have a protection circuit.
The hint that it was the protection circuit that was tripped was the fact that moments after beginning charging, they would immediately bounce to somewhere around 2.6v without any kind of a ramp from 0v. So I don’t think there has been any damage. They were being stored somewhere just above 2.50v on the battery side of the protection circuit. I suppose that a resting cell of around 3.65v when shipped doesn’t have a lot of capacity between there and the 2.50v trip point. And thus micro-amps of parasitic drain adds up when you’re talking 2 years. Lesson learned here.
