1.5 volts is too small a voltage to do most things. AA, AAA, C, D batteries all put it 1.5v per cell because of the chemistry involved. Things that use lithium batteries actually do often just use 1 cell sometimes because the chemistry of them puts out about 3.7 volts. Same with things that use 9v batteries. 9v batteries are actually lots of little 1.5v batteries (watch battery size) stacked up inside that case.