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4x4FF's avatar
4x4FF
Explorer
Apr 07, 2016

Question on power hookup

If I have my 5th wheel plugged in to the 110v power and also plugged into my truck at the same time does it hurt anything??
I realize some trucks have a relay that kills the 12v power to the 5th wheel unless it is running but am I hurting anything even if the truck is running for a few minutes?

Steve
  • valhalla360 wrote:
    Shouldn't hurt anything. If it's an older truck, it may actually top up the truck battery (not that it would typically be down after a drive)


    X2, should not hurt a thing!
  • Shouldn't hurt anything. If it's an older truck, it may actually top up the truck battery (not that it would typically be down after a drive)
  • I often hitch up the night before we leave with the trailer still plugged into 30 amp service to power the residential fridge as well as plugged into the truck. The hot lead on the Ram's 7-pin Pollak receptacle is hot with the truck on or off. No problems at all doing this.

    The battery isolation relay that some trucks use in the B+ (pin 4) circuit to the trailer is there to prevent the trailer from drawing down the truck's batteries if left connected for extended periods of time with the truck's alternator not running and the trailer not plugged into shore power. In my case, the net effect as far as the truck is concerned is that the power converter in the 5th wheel is keeping the truck's batteries topped up just like a battery tender would.

    Rusty