In one respect, voltage is like water: you don't appreciate its value until your supply runs low. Low-voltage systems, defined here as a single power supply less than 5 V, teach us to appreciate ...
Assuming that they're in series, 6v nominally for alkaline, as low as 4.8 for NiMH. Batteries are specced in Amp-Hours, not amps--amperage is a rate, Ah is a quantity indicating the amount of energy ...