My situation may be a little differ than yours, as my charger will charge two batteries or four batteries, but not three. So, I bought three four-battery packs giving me four sets of three batteries and rotate them sequentially. It is not perfect, but I did not have a better idea.
I didn't think to buy three. Then again, I don't see a 3-pack available. So I have the 3 which came with the unit, and the 4 Powerex I purchased, which I plan to swap back & forth. I'd have to buy 2 more sets of 4 Powerex to get me to 12 (and thus a factor of 3), which would be a total of 15 batteries, which is a bit much.
I guess I will mark them 1-4 and rotate them. I have the C9000, which takes 1-4. It's a terrific charger.
I do rotate mine. In addition, I carry the 'odd-ball' with me on short trips. When the low battery beeping starts, I replace one of the three batteries with the odd-ball. I also have the batts numbered.
Replacing just one cell with a charged cell might clear the beeping but it is a great way to ruin your other 2 cells. Rechargable cells do NOT like to be reverse charged, doing so will destroy the cell in a very short time.
Replacing just one cell with a charged cell might clear the beeping but it is a great way to ruin your other 2 cells. Rechargeable cells do NOT like to be reverse charged, doing so will destroy the cell in a very short time.