Wondering if anyone has knowledge of the amount of power that transfers through the 7 pin wiring harness to a trailer battery while attached. I have a 2021 Ram 2500 Cummins with a 220 amp alternator. There appears to be solutions to ship more power down the line to the trailer like Renology. But I would prefer to understand what i have now for charging batteries while towing. TIA.
Ram Heavy Duty Forum
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7 PIN Trailer Wiring Harness power
- Thread starter Danishgod
- Start date
H3LZSN1P3R
You're doing it wrong
Typically the battery + wire is fused at 30A so it should be around there i have not tested it though
CdnHO
Well-Known Member
The factory trailer wiring won't give you much charging current due to the gauge and length of wire. A meaningful charging current will require a heavy gauge wire to the back of the truck, a heavy duty connector at the back bumper and some sort of charge controling device on the trailer.
I've seen mention of 9-10A charge current max at the RV battery by the time it gets through all the wiring.