I have several AW Black label and Battery Stations Yellow label 3.7v Protected RCR123's. I don't mix the two brands. Some are used as a set of 3 or 4 for the SF-V's, other 3 sets for the SF 9Z w/Turbohead sporting an 'ARC mania' TTM, some 2 pairs for Flashlights having a P60 LED drop-in and some used for single cell illumination tools.
During my play times and discharging several cells in a day, I use two of the UltraFire WF-139 chargers. At times I forget which batteries went to what Flashlight and have started to mix them up. Once I find the answer, I'll label them as sets 'A', B', 'C' and so on.
Question... Since most of my toys has different demands on the cells, and I get comboobberated on which cell went where... Is there a MAJOR concern of me mixing the RCR's AFTER they receive a full charge?
I am still going through the trial and error process to get the cells back to the proper sets. One cell's protection circuit kicks in too soon in my book on a 3 cell'd Flashlight and I have removed that cell from this 3 set.
Added question... If I start to use the cells in fixed sets and I discharge and charge them several times... will they eventually become somewhat of a match for each other regardless of past use? Most cells are of several months apart in age but I forgot how many discharge/charge cycles they each could have had.
Another added question... Do you think testing each cell on a single cell Flashlight to do a run time test and note the time to full charge then sort them accordingly? I'm sure as the cell degrades, those values would change.
If anyone here that reads this that can answer the questions with battery knowledge or actual experience, please post here. And if you are wrong and damage occurs... you owe me a new Flashlight, batteries and a charger

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Njoy...