Some good info. on batteries and charging on Battery university and Candlepower forums. It seems that fast charging is not good even though some of the Panasonic Eneloop chargers are quite fast. One expert reckoned a charging rate of about 0.2C (0.2 X capacity) was about ideal which would equate to a 500mAh charge for about 6 hrs . 30 minute rapid charging is certainly not recommended.I try to keep my cells in pairs and try to avoid mixing them up.I put several through a break in cycle on a Maha Powerex charger analyser a couple of weeks back and there was some variation in capacity but the worst ones were still only about 200 mAh down on the best and some had seen a lot of use.It is the white Eneloops which seem to be the stuff of legend and I tend to use them in all my remote controls, clocks etc.