Relying on sources here and elsewhere, I had a hunch that the base charger could be powered from a 9v battery. I have a 9v attached to a type M barrel connector for an Arduino (another neat bit of kit), so I plugged it into the base unit. The LED went red, as if it had been plugged in to the wallwart. I dropped the UV-5R into the base, and the LED went out, as if under load.
– A 9-volt battery isn’t much of a power house, huh? –
(Seen on the UV-5R group)