Car audio second battery?

Can I buy a second battery for my car audio needs for my car and just connect it to my alternator so it can get a charge, or do I need a isolator?

5 Answers

  • 2 months ago

    You can have a 2nd battery parallel with the first one for more available current. If you use an isolator, that will keep the stronger (newer) of the batteries from being slightly drained back into the older one while the car is off. You can use 2 batteries without isolation, but it's better for the batteries to have an isolator. 

    That will not make your alternator into more powerful a power source, and it will have more work feeding two batteries and the stereo. Decide if you need the extra power to run your system, and if it might do better to get a stronger alternator so every appliance gets fed sufficiently. Get out your calculator and add up how much power everything uses, how much the battery has and if the alternator can keep up with the needs.

    You didn't tell us anything about your system, we're left guessing what needs you have- or not. Maybe you don't have a problem, but want more electrical power.  "Want", and "need" aren't always the same.

  • Anonymous
    2 months ago

    Connect in parallel to first battery.  Charge battery before using.

  • Barry
    Lv 5
    2 months ago

    Just connect it to the original battery in parallel. Positive to positive and negative to negative. That way the alternator will charge both batteries simultaneously. No other action is needed. But make sure the second battery is clamped down securely.

  • Anonymous
    2 months ago

    That depends on why you think you need a second battery. If it's because you listen to music a lot with the engine off, then yes, that will help. If it's because you have a powerful system, especially with a high power subwoofer amplifier that causes the battery voltage to get low with the engine running, then what you need is a higher output alternator. 

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  • Sure, you can use a second battery.

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