Voltage Low in 2016 International Prostar below 12v

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Datboijean954, Jan 16, 2023.

  1. Jan 16, 2023 #1
    Datboijean954

    Datboijean954 Bobtail Member

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    I have an 2016 international prostar Cummins engine i apparently was losing voltage below 12.v went to TA and told me i had dead batteries ok change all 4 of em, couple hrs later same thing happening losing voltage below 12.v…..i don’t understand he even checked the alternator it was fine what u think the problem is? Plz help
     
    Datboijean954, Jan 16, 2023
    Datboijean954, Jan 16, 2023
    #1
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  3. Jan 16, 2023 #2
    ducnut

    ducnut Road Train Member

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    Batteries off the shelf take time to fully charge. You can’t just install them and start pulling off them.

    With the truck running, what voltage at the batteries (or inverter if it’s directly connected) are you seeing?
     
    ducnut, Jan 16, 2023
    ducnut, Jan 16, 2023
    #2
  4. Jan 16, 2023 #3
    201

    201 Road Train Member

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    Bad ground to frame.
     
    201, Jan 16, 2023
    201, Jan 16, 2023
    #3
    ducnut Thanks this.
  5. Jan 16, 2023 #4
    DUNE-T

    DUNE-T Road Train Member

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    Can be bad signal wire
     
    DUNE-T, Jan 16, 2023
    DUNE-T, Jan 16, 2023
    #4
  7. Jan 16, 2023 #5
    Mr Bob

    Mr Bob Light Load Member

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    Sounds like your alternator is not charging and you got ripped off. A hard charging alternator will be hot.
     
    Mr Bob, Jan 16, 2023
    Mr Bob, Jan 16, 2023
    #5
  8. Jan 17, 2023 #6
    Goodysnap

    Goodysnap Road Train Member

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    Why would a brand new battery not be fully charged? It most certainly should be.
     
    Goodysnap, Jan 17, 2023
    Goodysnap, Jan 17, 2023
    #6
  9. Jan 17, 2023 #7
    201

    201 Road Train Member

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    Actually, a hot alternator indicates a bad ground. I drove a Mack, started going through alternators, the boss asked, "is the alternator hot?" I said, can't even touch it. They ran another ground to the motor, and viola! I think the whole world has a bad ground today,,,
     
    201, Jan 17, 2023
    201, Jan 17, 2023
    #7
    bzinger and ducnut Thank this.
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