A useful thing for motorists and motorcyclists is a digital DC voltmeter with backlight. Due to the wide range of measurement values (from 2.5V to 40V), such a voltmeter can be used in charging for lithium-ion and other batteries with a small voltage.
Various protections are built into this measuring device, so it is extremely difficult to burn it (if without fanaticism of course: wink :).
It should be remembered that the backlight of the numbers starts working from 3V, a current of less than 30mA is needed to power the device.
Specifications:
Voltage range - 2.5-40V
Update rate - once every 200ms
Working current - <30mA
Operating temperature: -10 +65 degrees
Cost: ~ 25