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Thread: Car battery voltage...

  1. #1
    Newbie
    Join Date
    Jul 2001
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    4

    Post Car battery voltage...

    While driving in the car last night, I noticed that the battery voltage dropped well below 12.5volts, (12.29 to be exact) and I was wondering if there is anyway to prevent it dropping so low??

  2. #2
    Constant Bitrate
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    Nov 2001
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    Dublin, CA
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    Post

    If it is normally higher than that, which it should be, was there another event that was occurring at the same time? Like playing your audio system really loud?
    Did it do this just once and then never again?
    If your car and anything in it is drawing more current than the alternator can supply, chances are than you will get dimming lights and a drop in battery voltage. A sure fire way to prevent this is to get a bigger alternator or have the stock one re-wound to a higher amperage.
    High output aftermarket alternators are availible from AAMP of America and Ohio Generator.
    Car computer and console.

    Shuttle FV-24, 100gig, DVD, 10.4 VGA TFT, 866MHz, 128MB Ram, Keyspan remote, DC-DC

  3. #3
    Constant Bitrate monger's Avatar
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    Nov 1999
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    Good ole Maine. Gotta love trees and deer.
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    Post

    there are a few options...

    -new battery
    -new alternator
    -LARGE caps which would only last for about 1/1000th of a second. And the caps would accually be a detriment to the system after they had disscharged as they would also be trying to take power from the car to charge themselves.


    This is the problem with the flat-pack regulators. they have that nasty .5 volt drop accross them.

    good luck either way.
    Monger
    ICQ-7207702
    UPDATE: I moved farther north. Now its even too cold for the deer; only moose now

  4. #4
    Newbie
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    Jul 2001
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    well, it really only dropped that low while the headlights were on, the car was in drive, the brakes were applied, and the indicators were on..
    BUT!!!
    after it dropped below 13volts, nomatter how fast you revved the engin, (2nd gear going 60kms/h) the voltage would not go any higher than about 12.9..
    Its a New battery, but is 100CCA higher than the original one that was in the car, its also the 2nd time we have had to replace the battery in less than 4 years!!!!!

  5. #5
    Variable Bitrate
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    Oct 2001
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    Post

    bad alternator...should be 14.4v

  6. #6
    FLAC
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    Apr 2001
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    Here, There, Everywhere
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    Post

    the CCA/cold cranking amps will have no real effect to the output voltage of the battery under load.

    and this is why we all keep telling u that linear regulators are bad for a DC-DC supply!
    Project - GAME OVER :(

  7. #7
    Newbie
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    Jul 2001
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    Post

    yeah, well,
    I am still waiting for this new, super duper supply..

  8. #8
    FLAC DodgeCummins's Avatar
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    Oct 2000
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    The battery when charged holds around 12 volts.

    The alternator, in order to charge the battery, runs around 14 volts...otherwise it couldn't fully charge the battery.

    Most car alternators only put out that 14v to around 60 amps.

    You start using ignition, lights, fan, etc. and you quickly use up that 60 amps.

    Therefore if you use up that 60 amps, it will start pulling juice from the battery...at 12 volts. As the battery loses juice, the voltage drops.

    So things that can help are clean your battery terminals, make sure your alternator is running correctly, get a bigger alternator like 120 amps, get a bigger (more storage) battery.

  9. #9
    Maximum Bitrate
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    Dec 1999
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    Post

    Dodge, how did you rebuild your dash surround? I have a 2001 Ram myself, and your install looks very clean.
    KG6OQD
    www.americansandassociation.org

  10. #10
    FLAC DodgeCummins's Avatar
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    Oct 2000
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    Luckily you didn't look too closely

    The '96 and the next couple of years had a flat dash with a big hole behind for the large Mopar radio.

    I actually need to cut the dash trim plate more and do some fiberglassing so I can tilt the screen up a bit for better visability.

    So the reality is my display just fit...and the head unit just fit up in the cupholder.

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