Would it consume more gasoline to run the generator or the car’s engine? In terms of convenience, ease of operation, and likely noise levels leaving the car running will come out ahead.

The cigarette lighter wiring is too small to do much with. For any serious system you’re going to connect directly to the battery.

The generator has a 12VDC output which could be used to charge the battery. Its capacity is unlikely to keep up with what is being drawn and the battery will eventually discharge.

A standard automotive car battery charger could be used to keep the battery charged. Don’t go with the small 1A model if you hope to keep up with a high powered amplifier. You will need a much larger charger, possibly one with a 70A engine boost feature. The charger may induce a hum on the car’s electrical system which may find its way through to the audio gear as well.

If you can find a large 12VDC regulated power supply with proper filtering it could be used to power the audio equipment. Plug it into the 120V outlet on the generator. Paralleled with the car battery it could also keep the battery fully charged. There would be no noise induced to the audio gear either.

actually most small Portable Generators have a 12V output. They vary in current output but are not usually very big. They have a special plug and harness that comes with them. Most have alligator clips or cig lighter adapter. Yours give 12V at 8A. You can’t charge a battery because it is not higher than a battery normally. What you can do is run your radio off it if you are less than 8 Amps.

Another idea is to put a normal 120Vac powered battery charger on the battery posts and let the generator run that so you don’t drain your battery completely. Unless you are talking about a high powered amped stereo system. Then you are out of luck.

You just charged the 12v car battery? BS! Someone involved here has got to have a problem to sort out

Not unless that generator has a 12 Volt DC output on it. Not saying it doesn’t but it would be rare. I’ve never seen a gasoline powered Portable Generator that put out anything other than 120/240 Volts AC.