Only for a relatively short time until your battery is dead. The 12V system while the engine is running is supplied by the alternator, the battery just buffers it.

As proof, you can jump a car without a battery and the electronics will all work.

When the car is off the power comes from the battery. The batt gets charged by the alternator when the engine is running.

No offense, but you should just google “what powers the radio in my car?” r/Rev_Creflo_Baller is right, it’s the alternator (when the cars on) and battery (when the cars off). Guess what powers the battery and alternator?

Because you have a small charged battery which is used to start the car.

Run the radio for a while without starting the car, and your battery dies, and needs to be jump started.

Because your car has a battery. The battery can provide power to the lights, accessories, but most importantly the starter, which is used to crank and start the engine. If you leave those accessories on while the engine is off, it will drain the battery (we're talking leaving these things on for hours without running the engine). Drain the battery enough and it won't have enough power to start the engine.

Your car also has an alternator, which is basically just a small generator turned by the engine. The alternator turns some of the engine's power into electricity to power various parts of the engine as well as the lights and accessories, while also recharging the battery.

The car has a battery that will run the accessories and be charged by the alternator when the engine is running.