I purchased combo kit from Amazon.com with four AA NiZn cells and a "1 hour quick charger" made by Powergenix. I received them 2/16/2011. At random I will cycle all of my batteries (Eneloops using my LaCrosse charger/analyzer, NiZn using a single cell flashlight with a .9 volt cutoff) so keep their capacities strong.
Today I grabbed my four NiZn cells and discharged three of the four. The fourth one had a reading of .1 volts. The charger wouldn't recognize it. I used my LaCrosse charger to bring the voltage up to .5 volts then tried charging using the Powergenix charger. All it does is get VERY hot.
That's so crappy because I loved the high output of these batteries.
I had 8 of them and finally just gave up and put them in the battery recycle bin. They were completely inconsistent and most were coming in WAY below rated capacity.
Just a little update: Just because I was able to get the voltage high enough to charge...doesn't mean I should have charged the cell.
I realized that the one hour charger had been charging for...a lot more than one hour. I pulled the battery off of the charger and nearly tossed the battery across the room. It was so unbelievably hot that I was worried that it might explode. It is cooling down now but definitely going to be taken to the battery recycling center next week.
You discharged them far to deeply and ruined them. 0.9V is for NIMH, and even that is questionably low for most newer chemistries. NIZN should not fall below 1.30V (which is at the end of their discharge curve) or you will quickly ruin them. The 16 powergenix I have are over 1 year old and they still perform well, albiet not as well as when they were new.
FlashPilot beat me to it. I have about 24 of these batteries and havent lost any so far in the 4 months Ive had them. I dont let mine hit 1.2V before I charge them back up. On a side note my friend bought 12 of these batteries and has lost 4-5 of them already. I have now drilled it to him about overdischarging them.
So 1200mAh is fine? Mine had never been run anywhere near dead and ranged from 1300 to 700mAh. That's not fine to me. Not to mention, that if I have to babysit them to assure they won't get over-discharged, I might as well be using a li-on and getting more energy density.
In CPF, I was perhaps NiZn's most vocal champion; I think I'm still promoting them in my CPF signature block. But my experience mirrors that of KLowD9x, even though I use only the maker's better charger: the white "quick" charger (1 hour, fast, 4 channels), not the black "fast" charger (3 to 5 hours, dumb, 2 channels). When fully charged voltage straight-off-the-charger ranged from 1.72V to as little as 1.57V. I never knew when a NiZn cell would fail to charge. I still use them over NiMH where I can see a difference. But yesterday I placed an order for 8 AW 14500 cells: 4 of them protected LiCo, 4 IMR. All my lights these days are 1-cell jobs that can take 14500s, and I felt like a chump cheating myself out of the rated brightness.
I use them in my Zebralight SC51. They're brighter and last longer than Eneloops. I charge once it won't go into H1 and drops to H2. I have had one fail as well, but I have 7 more. The only reason I use them over my 14500 is that I don't think it's designed for them, not sure if it would hurt it long-term.
Mine probably failed by being overdischarged in a multicell light that mixed AAs of different capacities. I eventually learned not to mix a 1.55V NiZn with a 1.78V NiZn. But by then, the damage was done. Partly from this experience, I became interested exclusively in 1-cell lights: It's easier to "see" when voltage is too low. And when the light grows weak, there's no doubt which cell needs charigng.
