2016 cascadia dd15 High charging voltage intermittent

Discussion in 'Freightliner Forum' started by IMSITTINGINYOURCHAIR, Dec 9, 2019.

  1. IMSITTINGINYOURCHAIR

    IMSITTINGINYOURCHAIR Bobtail Member

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    Sep 14, 2019
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    I've not done too much digging into it other than basics, wires all tightly connected at batteries and alternator. noticed a problem this morning rolling out of the rest area, my trailer abs light was on and then later my inverter cut out along with my hvac and abs module must have too as I got both abs lights with the trailer staying on after. knowing that all three live on their own power bus, I looked to the batteries and charging, I kept the volt gauge on and it spiked and held 15.6 for a minute, it did this about three more times today. I have a small parasitic drain that I think may be the alternator now but haven't had time to properly diag that, just keep it on a charger when I'm home and run a generator to power acc when i park overnight.

    addtnl information: I am not sure on the control side of the alternator, I tried something today while driving, 65mph, down hill some, i turned the key off and the alternator kept charging, so to stop that, clutch in, engine totally stopped, voltage reading on my inverter display settled at 13v then to 12.9, key off, i eased the clutch back out to restart the engine without getting the computers involved and the alternator immediately started charging back to 14.5 I'm prob wrong, but my understanding of automotive charging tells me that the alt needs power to get started and a computer controls that with the key on.
     
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  3. IMSITTINGINYOURCHAIR

    IMSITTINGINYOURCHAIR Bobtail Member

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    Sep 14, 2019
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    Well, the problem seemed to go away for about a month. Today it reached new heights. Literally. 17.5 for a couple minutes straight and ohhhboyy did I have bright headlights I started probing fuses and literally the first one I checked was the remote sense. 5 amps. Blown. Going to replace it and see what happens
     
  4. IMSITTINGINYOURCHAIR

    IMSITTINGINYOURCHAIR Bobtail Member

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    Sep 14, 2019
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    Seems like it is working better now. Charging at 14.0 instead of 14.5 - 14.9 I will probably need to investigate the sense wire to be 100% sure it's not touching anything but at the alternator and a few inches back, it looks okay.
     
  5. uncleal13

    uncleal13 Road Train Member

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    Humboldt, Sk
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    When my 2016 Cascadia was new, it was charging at 14.6 volts all the time. I found the same voltage sense fuse blown, now it reads 14.0 volts for over three years and never blew again.
    Must just be a cheap fuse from manufacture.
     
  6. IMSITTINGINYOURCHAIR

    IMSITTINGINYOURCHAIR Bobtail Member

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    Sep 14, 2019
    0
    Probably, it vaporized the link but there was no soot on the fuse to indicate a high amperage short, oh well. I think the high voltage might have de sulfated my batteries though. Standing voltage this morning with normal loads was better than the last couple weeks.
     
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