batteries

im just wondering how many amps and volts the piccoboard can take.
i have two sets of batteries.
the origional picco pack
it has 7 cells and they are 250mAh each and 1.2v each.
the other pack i have is an 8 cell sanyo twicell 700 pack these are 1.2 v each and are 700mAh each (i think?).

i have been looking in a copy of the maplin catalogue and there are lots of the AAA batteries.
so i was thinking of making my own pack and just wondering how may batteries i can use as not to overload the circuit board