Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

Is it this simple or would I need some electronics to regulate to
output voltage?

If its not just a case of batteries, box and a connecting lead, any
pointers to suppliers of the necessary kit would be appreciated.

dg