I have some Panasonic Infinium (LSD) AAA batteries that won’t charge in my little Panasonic charger at work. So I tried them in my fancy Powerex charger, and it says “high”, which apparently means too high resistance. My AAA Eneloops are fine. I originally charged all of them in an Xtar VC4, probably one at a time, and my guess is that the Xtar shoved 1A through which has damaged them. Comments please. Is this likely?
Oddly these cells haven’t seen a great deal of use, I now use one in headphones, and they’ve had a few charges for use in a Jetbeam jet mu.
My experience with AAA of any sort is that they tend to be ‘fragile’. It’s easy to charge them too ‘hot/high’. They fail termination more than other cells (end up being overcharged and HOT), and it’s easy to over discharge them, which causes damage. All that contributes to high internal resistance and degradation. I’m in the middle of checking the capacity and resistance on all my battery stock with a theoretically more reliable electronic load tester than the stock analyzing chargers. It does seem to be a lot more consistent. IR for analyzing chargers can be very inconsistent. The higher the IR, the worse the results has been my experience. But, that still tells you something.
My newest/best AAA seem to have an IR of 40-75. The older ones are often 500-900+. In general I’ve seen that the really high IR cells may be the one’s that miss termination, or terminate before being filled, often very soon after being put in. But, I’ve also seen cells with lower IR miss termination. NiMh is simply harder to charge than Li-on. I don’t have any chargers that depend on IR to function.
How fast do AAA go bad? I don’t know. I’m just getting a handle on this myself. I’ll be interested in some other input on this also.
There are some Ni-MH AAA batteries (and eventually some AAs) that I can’t charge on my Opus charger.
They may go “too low” and the charger doesn’t recognize them, showing “NULL” on the display.
Them I pick my Nitecore Digi D2 and put them in and they start charging. All the time I have this situation, the Nitecore is the solution.
Some smart chargers will not charge a zero volt cell. Some will.
This is where a dumb charger comes in handy. Put them in a few minutes > cell takes a small charge > put them in the smart charger to finish.
Oddly, when I do this, with very little charge on a dead cell, when it’s put in the smart charger it will often see it as having something like 1.35v. If I put in a very low cell, the voltage reading will be more in keeping with the actual voltage. Some indication of damage with that? Don’t know, but I suspect it is.
BTW, occasionally the dumb charger trick will not work. Then you can ZAP it > connect + to + and - to - with a full cell, or even a Li-on cell……very briefly. That will usually get it going again. I mark those cells and figure they are on their last legs.