On Tue, Jul 19, 2016, at 18:17, Marko Rauhamaa wrote: > I'd love it if batteries were priced per joule, or even per > kilowatt-hour.
Typically their capacity is labeled in amp-hours. You have to know your devices to know if the voltage difference between different battery types (Which ranges from 1.2 to 1.7 for nominal-1.5 AAA/AA/C/D cells, and may be lower under load) is significant or not, and in what direction. A lower-voltage battery in an incandescent flashlight will last longer but not be as bright. No idea how it shakes out for LEDs, motors, or complex electronics. Some devices may not be operable at all below a certain voltage, and of course the voltage reduces over time as the battery is drained. There are just too many variables, and even the nominal amp-hour rating assumes a certain discharge rate. And of course, for rechargeable batteries there are even more variables; but there what you're buying isn't power. -- https://mail.python.org/mailman/listinfo/python-list
