Second car electrical system?

I have an old mercedes (1974) and i want to put a new sound system into it, right now its got a new deck and some 300W 6X9's and its bad enough at normal listening volume that my lights dim. It used to have air conditioning but it was taken out and sold before i owned the car and i was wondering if i could get a second alternator and put it in where the a/c used to be and wire it to a second battery and just have a whole separate electrical system for my stereo so i don't need to worry about messing anything like wipers and lights etc. which run on the existing system. I'm just wondering if anyone else has done this or knows what i would need to make it work.

thanks for reading


could you include a list of parts i would need to get other than mounting hardware for the alternator. thanks

4 Answers

  • 1 decade ago
    Favorite Answer

    yes that is possible.

    if you are having dimming problems with just a deck and speakers then you have electrical wiring problems in your car that need to be fixed before you add anything else .

  • Anonymous
    1 decade ago

    I would suggest looking into a capacitor for your stereo system. Typically a 1 farad capacitor will take the edge off of the draw from the stereo and stop the dimming problems, they typically cost $40+. If you really must mess with the alternator i would suggest getting a larger alternator rather than 2, as well as a marine battery (which combines deep cycle with high current output).

    Hope that helps

    Source(s): 4 Years as Car Audio Installer
  • Anonymous
    1 decade ago

    i recomend upgrading the 3 main power wires first with thicker cable the ground from the battery to the chassi n the ground from the battery to the engine and the positive on the battery to the altenator with thicker wire i recomend something near 4 gauge and then if u still have problems upgrade to a high output altenator and if that doesnt work your car would need a rewire cos their is a short somewhere

  • 1 decade ago

    Yes it can be done, make sure your new belt is the right length and that the pulley is perfectly lined up

    make sure you have a good in-line fuse - Good luck

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