Renogy DC-DC Charger wiring diagram-compressed.pdf
We generally camp where we have electrical hookups but sometimes we want to live off the batteries for a couple of days. We do not have solar at this point but I may consider adding it in the future.
I have not been satisfied with the ability of the WFCO Converter Panel to properly charge the batteries. I have never seen a charging voltage of over 13.6VDC and generally it floats at 13.1-13.2VDC. Consequently my two deep cycle batteries never have a full charge and are probably closer to 70%. In the future I may replace the deep cycle marine batteries with AGM or lithium to gain more capacity.
I researched possible chargers and discovered that Renogy (known for their solar equipment) sells a 20 Amp DC-DC Charger which is intended for use on a Class A, B or C motor home to charge the "House Batteries." It is capable of charging lead acid, Gel, AGM and Lithium batteries depending upon switch selection. They are priced a little more than $100 on Amazon so I purchased one. I also ordered the optional temperature probe so that the Renogy Charger can compensate for the temperature of the battery. The description is "Renogy Battery Temperature Sensor Battery Temperature Sensor on-board Battery Charger."
Also I purchased a Battery Switch capable of handling 2 batteries with an OFF position. Mine is made by Blue Sea. I found it expedient to purchase 3 sets of 20-Inch Battery Inverter Cable Sets and a 8/10 Gauge AWG in-Line AGU Fuse Holder with 40 Amp Fuse.
I added a Charger Switch so that the Renogy can be set to not charge regardless of the Battery Switch position. This is technically not required as I wired it so that the Renogy will only charge when power is available at the input positive terminal of the Charger. The ignition switch in the truck controls the power going to the trailer connector. This means that when the truck is OFF that the Renogy likewise turns OFF.
The new system performs as I have always wanted,
1) When towing I leave the Battery Switch in the OFF position with the Charger Switch ON. The Renogy boosts the voltage from my truck to properly charge and maintain the batteries.
2) When camping and AC is available I set the Battery Switch to Battery 2 and the Charger Switch to ON.
3) When dry camping without external power I set the Battery Switch to Battery 1 and the Charger Switch to OFF.
4) When storing the battery I switch the Battery Switch to OFF and the Charger Switch to OFF.
There is a bright green LED on the Renogy Charger which shows when it is active.
I have attached my wiring diagram and several photos of the installation. The Inverter was already supplied by FunFinder on my model. The 4 AWG cables between the batteries and connecting to the Inverter were all OEM.
This project was an outgrowth of my investigation to determine why my Odyssey AGM batteries failed in my truck. I discovered that a normal automotive alternator will not properly charge an AGM battery unless the internal regulator is changed so that it charges to a higher voltage. This led me to understand why the deep cycle trailer batteries exhibited such poor amperage capacity.