...
The E36-RE used NiCad batteries so I wonder how one would power one up today. i remember a two part battery pack in clear blue plastic shrink covering. Maybe sub-C units?
NiCd batteries have a 1.2V nominal voltage, you can exchange it with a NiMH battery which has the same nominal voltage (and more mAh per unit volume), or you can put in a Li-Ion (or LiFePO4 or whatever) as a replacement for 3 niCds, with two dummy batteries (essentially a cable pass-through, no power) + 1 Li-Ion battery
NiCd ==> 1.2 x 3 = 3.6V (nominal),
Li-Ion ==> 3.7V (nominal)
Li-Ions have even more mAh per unit volume, so you have room to host a Li-Ion battery pack inside a NiCd battery pack.
Ciao from Massimo