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map40's avatar
map40
Explorer
Jul 31, 2017

National RV Dolphin not charging batteries

I have a 36 class A that sometimes it doesn't charge the coach batteries. Even when plugged in, the batteries get low. If I jump them with the engine battery, suddenly everything is OK, even after I take the jumper out, suddenly the 12v charging system works, and the batteries start charging again. Any ideas?
Class A

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  • MrWizard's avatar
    MrWizard
    Moderator
    Jul 31, 2017
    should Not be ANY relay between the converter and the batteries

    bad connection at post or cable

    converter is failing
  • enblethen's avatar
    enblethen
    Nomad
    Jul 31, 2017
    Charge relay contacts not closing or the control conductors could be corroded.
    Start by checking the control voltage to insure it is getting to the studs of the relay.
    Next when energized insure that the voltages on the large studs are the same when relay is energized.
    This could be the same relay energized by the Aux start switch if equipped. By operating this relay manual, the control circuit could be providing higher voltage to insure closure.

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