While ordering my Marantz PDM 660 with basic mod, Mr. Oade referred me to an “awesome battery recharger.” I read some more about it, and gosh, it is absolutely awesome. Among other things you can change the settings to discharge completely, switch between fast recharge mode (which apparently is harsh on battery life) and gentle recharge mode. Also, you have a display to let you know the relative charge level of each individual battery and the status of recharging. (How many sets of batteries have I thrown away just because one of the batteries might be run down or defective?).
(It’s called the LaCrosse Technology BC-900 AlphaPower Battery Charger and it’s available on amazon.com for less than $50).