> but the inefficiencies in power conversion would probably be a major downside (you're losing some energy on the conversion even if the device itself is powere

> but the inefficiencies in power conversion would probably be a major downside (you're losing some energy on the conversion even if the device itself is powered off). You can get around this[0] by starting the power converter in series with the battery (so the load pulls current through it to start it up) although that's: a: complicated, b: more conversion overhead when it is running, and c: rather difficult when you only have 1.5 volts (or 1 volt) to work with initially, compared to eg a 9-volt or 12-volt battery, which exacerbates problems a and b. /-[starter]-+---\ ˍ˖ | | | | Ξ [regulator] [LOAD] | | | \----+----------/ 0: At least to the standards of the quiescent depletion being a rounding error compared to the battery chemicals breaking down over time.