[Namuna]

3 x 1.2v = 3.6v + 20% (because the actual voltage of a charged pack is higher than the rated) = ~4.3v

So, to properly get a full charge...You can use 3 FRESH alkalines (3 x 1.5 = 4.5v) or 4 nimh (4 x 1.2v = 4.8)