Far-seeker:
All the "Latin letter" sized alkaline batteries (AAA, AA, C, & D) are nominally 1.5 VDC so you can connect them serially to get higher voltages. In fact you should be able to find cases for 4 AAA or AA batteries wired this way fairly easily.
Note, rechargeable Nimh batteries are 1.2 volts, not 1.5 volts. Also alkalines start out at 1.5 volts, but they do drop voltage as the battery gets depleted.