Voltage Booster #NGVB-HC
It can supply,
3.5 amps with the engine off.
5.0 amps with the engine running at a fast idle.
10 milliamps current draw with no load.
Most, AM/FM CD/CASSETTE PLAYERS
Power source - 10.8v to 15.1v allowable
Maximun current consumption - 10 amps
To maintain radio station presets & clock time - 20 milliamps
Maybe a smaller rechargeable 12v battery would work?
Like a D size flashlight battery. If they make them that small.
