How long will the average car battery last with an average 4 speaker car radio on aux. power with the car off?

I have a 1991 Toyota Corolla with a 4x50 Watt Sony CD Radio MP3 and 4 10 watt speakers installed. How long can I have it on aux./accesory power without killing my battery to the point where it won't start? Car works perfectly.

6 Answers

  • Favorite Answer

    Your situation depends on how good your battery is. A good battery running a Stereo and your stock speakers should be good for at least two hours. Your really consuming about a total of 60-Watts if you have the music at full volume. Most headunits dont put out what they claim, especially Sony units. I know I've had plenty. Turn your car on every 30 minutes just to make sure you dont get stranded with a dead battery.

  • Anonymous
    1 decade ago


  • 4 years ago

    I'd expect them to last at least 5. When I sold my old car, the battery was 7 years-old and it worked fine. I replaced the battery in my current car when it failed after 6 years.

  • 1 decade ago

    A long time. Take the CCA rating of your battery and divide it by the amps the sound system is taking. E.g.: 300 cold crank amps divided by 4amps (cranked up loud.) I'd say at least 2-3 days and still be able to start.

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  • 1 decade ago

    yes itll run like 2-4 hours.... but if your going to do this is suggest getting a capacitor so it keeps the battery charged that much longer....

  • Anonymous
    1 decade ago

    it ought to go 2 to 4 hours, but it is hard on your battery, they aren't made to be run down like that :(

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