Resurection

Discussion in 'The Projects Forum' started by CRY&PRAY, Feb 20, 2014.

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  1. CRY&PRAY

    Thread Starter Member

    Jan 6, 2014
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    It's always me!, resurrecting this old post, how can i run this amp with a car battery? i would like to get a +-12 v or more from the battery to feed this amp, i'm going to build it in a small enclosure to drive my woofers in the car.

    http://forum.allaboutcircuits.com/showthread.php?t=94344
     
    Last edited: Feb 20, 2014
  2. Experimentonomen

    Member

    Feb 16, 2011
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    Havent you read the forum TOS ? No automotive modifications/enhancements allowed, this includes plugging a cellphone charger into the ciggylighter plug in the dash.

    *waits for thread closure*
     
  3. wayneh

    Expert

    Sep 9, 2010
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    My understanding (could be wrong) is that accessories that plug into the socket are not restricted unless they have other obvious safety problems. They do not modify the stock vehicle.
     
  4. tcmtech

    Well-Known Member

    Nov 4, 2013
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    I would have to agree that this does not sound like a direct modification of any part of an actual vehicle or its electrical system.

    By my reasoning its modification of something that can be put in a vehicle but then most every project ever discussed here could be put in a vehicle too.

    I say let the thread play out.
     
  5. CRY&PRAY

    Thread Starter Member

    Jan 6, 2014
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    okay, sry, well the question is: how to mod that amp for a 12 v power supply (12-15v swing). I've made that amp by myself but i cannot get ti running in single rail :(
     
  6. tcmtech

    Well-Known Member

    Nov 4, 2013
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    I would say that usings simple push pull power oscillator to make a DC to DC converter would be the simplest way to get the +- 12 VDC you need.
     
  7. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    OK . This time you SHOULD read this.
     
    Metalmann and RichardO like this.
  8. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    The simplest and cheapest way would be to buy a second battery.... they don't cost that much. You can get cheap motorcycle lead acid batteries for about $30 with about 15 A-hr capacity.

    Of course, an even simpler way is to buy a car amp which has a switcher built in so it only needs 12V to run on. They are dirt cheap too.
     
  9. Experimentonomen

    Member

    Feb 16, 2011
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    But a commercial caramp will be an automotive modification as you have to hack into the electrical system by drawing a fat cable from the battery, through a fuse, through a hole in the firewall and back to the trunk to the amp.
     
  10. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Installing car amps is in no way an Automotive modification.
    Drilling holes in the firewall is a no no!.
     
  11. CRY&PRAY

    Thread Starter Member

    Jan 6, 2014
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  12. tcmtech

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    Nov 4, 2013
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    Yep that's the sort of circuit I am talking about. Just wind your secondary to the voltages you need.
     
  13. Georacer

    Moderator

    Nov 25, 2009
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    Lighter plug circuits are allowed in an automotive environment in AAC, but we all know that a subwoofer amplifier draws much more current than what a car lighter plug can supply.
    You'll modify the car circuitry and we all know it. Prove me wrong, if you want.

    I'll probably close this thread soon, I'm just waiting for a convincing counter-argument.
     
  14. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Still Wiring a cable from battery to car amp is allowed.
    But no drilling holes any where.
     
  15. Experimentonomen

    Member

    Feb 16, 2011
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    If you are lucky enough that there is already a existing hole in the firewall to run the cable through.
     
  16. Georacer

    Moderator

    Nov 25, 2009
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    No, tapping onto your car battery is not allowed.

    As I said before, car-related circuits are allowed only if they don't tap onto the car electronics at all or merely plug onto the lighter plug.

    Tapping from the DC voltage of the battery directly is not allowed.
     
  17. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    The lighter plugs will typically handle upwards of 25A. I remember I had a rear window defroster that plugged in that sat in the back. Ended up getting the plug hot enough that the plastic deformed.:p
     
  18. bountyhunter

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    Sep 7, 2009
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    I really doubt that. Most cigarette lighter outputs are fused at 20 or 25A which is close to 300W continuous. Sub amps have ridiculously high (and often FICTIONAL) power ratings but don't operate anywhere near those numbers for average power. large caps near the amp would handle the peaks. IMHO, even ground shaking loud music would probably never exceed about 25W RMS (continuous) power.
     
    Last edited: Feb 21, 2014
  19. tcmtech

    Well-Known Member

    Nov 4, 2013
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    Easy way around that. Wink Wink Nudge Nudge. :p

    The OP just has to say he has a ex police car that came from the factory with the high current feeder line to the trunk that the some of the police package cars had for the additional high powered electronics they stuffed back there.

    A buddy of mine has a old highway patrol car of which he asked me what I thought the big wire was for he had in the trunk. Best guess was it was the power feed for the old patrol car electronics. That's my theory and I am sticking to it! :D
     
  20. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    A lot of them had a second battery in the trunk. They also had a high output alternator.
     
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