Renogy DC-DC house voltage

[critical367]

I have the 30A combo MPPT DCDC charger in my travel trailer. When connected to the car for DC-DC charging, it reads the trailer battery voltage as 14.4 and cycles on and off with the Renogy app reporting boost mode. Same thing with solar panels connected or not. With only solar input, it reads correct 13.2V as verified with multimeter, and shows bulk mode. So the DC-DC charge is not optimal. Everything is wired according to the manual. Appreciate any suggestions.

 

[fratermus]

A high-resistance connection (including undersized wiring) could make the house voltage read higher when charging currents are larger (alt charging) and lower under gentle charging (solar). If there's a long wiring run between the DC-DC and house battery I'd suspect that. I think this and teh 50A have a way to back down charging current. If so, you could do that and see if the readings normalize.

If this is the issue one might make use of the voltage sense ("Battery Voltage Sampling" #7 on the diagram in the manual). And make sure there is no loose connection or high resistance throwing things off.

 

[critical367]

Thanks. There is 4 feet of 6AWG from controller to the battery. But your tip led me to check voltages and the circuit breaker between it and positive bus seems to have drop across it so I took it out but still having the same issue. Waiting to see if Renogy support has an answer.