I'd be leery of using a different power supply with the DSD. We don't really know how much of the charging "smarts" are in the charger and how much are in the adapter. If using a different power supply makes the batteries charge more quickly, it sounds like there is some current limiting going on in the power supply. You cannot rely on any old power supply to properly limit the current for the purpose of charging lithium ion cells. The charger was designed for some current level - higher currents may be outside the design criteria, giving unpredictable results. In my opinion the DSD charger should be treated as an immutable package, especially given the potential dangers of lithium ion cells.