On 20/12/2020 16:53, Max Demian wrote:
On 20/12/2020 14:42, williamwright wrote:
On 15/12/2020 15:42, Dave Plowman (News) wrote:

Think it's a very long time since I've had a radio that would run the
battery flat while stopped for half an hour or so?


Don't they have a row a little valves nowadays then, and an inverter?

An inverter would be rather posh. More likely a vibrator power supply.


AIUI there were valves developed to run off 12v HT specifically for
use in automobiles.