Alternators and batteries, general question

Discussion in 'Trucks [ Eighteen Wheelers ]' started by mickeyrat, Nov 11, 2013.

  1. mickeyrat

    mickeyrat Road Train Member

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    Nov 24, 2011
    on my 30 min break
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    Had/have an issue that set of new batteries didnt seem to address.

    So now I'm thinking alt going out? Question is , so they just quit or will they slowly fade in charging the batts? New set today started with 14v at speed. Drove the new set for 3 1/2 hours. Get to first stop come back out and voltmeter struggled to hit 13 v and fluctuated the rest of the day. Previous with old batts and including today with the new ones in, after about 20 30 min the power to cab cuts out. Bunk heater causes the same ,will run but no other power available. I use Cpap and I'd rather be rested and safer but still stay warm too.

    How long drive time til batts are fully charged after install and the above question on how alts go out.

    Thanks in advance. Company driver trying to learn from you helpful folks.
     
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  3. Heavyd

    Heavyd Road Train Member

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    Feb 4, 2009
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    Sounds to me like there is a bad connection somewhere causing intermittent problems. Too many variables in how long to recharge. Alternators usually work or they don't. They don't typically get "weak". Bad grounds, loose or corroded connection are more common.
     
  4. indspirit

    indspirit Light Load Member

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    Aug 17, 2013
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    I had the same sort of problem on a 2001 freightliner columbia it turned out to be a corrosive ground wire. Took my mechanic 2 days to find the problem.
     
  5. darkknight82

    darkknight82 Bobtail Member

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    Nov 8, 2013
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    check amps at the outlet of the alt. then amps at the batt. do that with the load (all acc) and no load. ur looking for low amps at the batt and the alt with acc off and higher amps with acc on if u have low amps with accessories on at the alt replace alt
     
  6. topitopi

    topitopi Bobtail Member

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    Nov 12, 2013
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    Check the ground wires, normally corrosive, or broken
     
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