Missileman - the wall wart chargers designed for 4.8 volts CAN charge 5-cell packs. I have done it many times. The wall wart chargers are current-limited devices. Here's one way to prove I'm right. Take an aileron extension. cut the red wire somewhere in the middle and strip off some insulation. Connect your ammeter in series with the charging circuit. When I do this I can measure that a 4-cell pack gets charged at 50 mA. Disconnect the 4-cell pack and connect a 5-cell pack. The charge rate drops to 40 mA but it is still charging. Charge the pack overnight and then discharge it using your discharger. You will discover that it has indeed been charged OK with the wall wart charger. After 7 cells, the charge rate drops off to 18 mA. I have done all my measurements and testing with JR wall wart chargers. But you should find similar results with any wall wart charger - they all work on the same principle.