How to Upgrade 2015 Fourwinds Coach Battery to LiFePO4

[CalifornioBill]

I have a 2015 Thor Four Winds 26A Model FC26A-15 Class C.
Trying to upgrade the old coach/house battery from lead acid (LA) to a new lithium /LiFePO4 battery.
Need to connect a DC-to-DC charger between the new LiFePo4 coach battery and the Ford E350’s chassis/starter battery;

• The RV has a WFCO WF-8955P Power Center w/ integrated converter & fuse/ckt-brkr panels. Where does the chassis battery 12V+ cable connect in the Power Center? Do I have to remove the Power Center to access it and install the DC-DC charger?

Any how-to or diagrams welcome.

 

[16ACE27]

The DC-DC charger goes between the house battery bank and the chassis battery. They cables for the current connection is probably in the BCC (Battery Control Center) under the hood as well as the latching relay controlled by the USE/STORE switch.

BCC info can be found in the RESOURCES area.

 

[Chateau_Nomad]

The DC-DC charger goes between the house battery bank and the chassis battery. They cables for the current connection is probably in the BCC (Battery Control Center) under the hood as well as the latching relay controlled by the USE/STORE switch.

BCC info can be found in the RESOURCES area.

Unless it's been modified, I doubt he has a latching relay. That's why I asked where his house batteries were. Under step battery setups on a class C usually have 2AWG cable between the house battery... through a resettable breaker... to a rotary disconnect in the entrance steps well... then runs back to the DC side of the power center... no latching relay needed.

 

[RVGeek-THOR]

I have a 2015 Thor Four Winds 26A Model FC26A-15 Class C.
Trying to upgrade the old coach/house battery from lead acid (LA) to a new lithium /LiFePO4 battery.
Need to connect a DC-to-DC charger between the new LiFePo4 coach battery and the Ford E350’s chassis/starter battery;

• The RV has a WFCO WF-8955P Power Center w/ integrated converter & fuse/ckt-brkr panels. Where does the chassis battery 12V+ cable connect in the Power Center? Do I have to remove the Power Center to access it and install the DC-DC charger?

Any how-to or diagrams welcome.

I have a 2015 Thor Four Winds 26A Model FC26A-15 Class C.
Trying to upgrade the old coach/house battery from lead acid (LA) to a new lithium /LiFePO4 battery.
Need to connect a DC-to-DC charger between the new LiFePo4 coach battery and the Ford E350’s chassis/starter battery:

• The RV has a WFCO WF-8955P Power Center w/ integrated converter & fuse/ckt-brkr panels. Where does the chassis battery 12V+ cable connect in the Power Center? Do I have to remove the Power Center to access it and install the DC-DC charger?

Any how-to or diagrams welcome.

Earlier this year I converted my 2015 (Chevrolet platform) Chateau 23U to LiFePo4s (two 100Ah Humdienks from Temu). Your setup should be similar. I am very impressed with the conversion for many reasons. The conversion required:

• Installing a Redodo DC-to-DC 40A charger which also served as a solar charger,
• Replacing the WFCO main board assembly with a Vevor WF-8955-AD-MBA assembly with a switch for the lithium batteries, rather than auto-sensing (which I don't trust) and
• Assorted fuses/breakers, cables and stand-off power studs.

I also installed a 100A battery monitor with shunt from AliExpress, as the lithiums have a rather flat discharge curve and estimating state-of-charge is difficult from voltage measured.

Basically, the AWG 2 cable from the battery isolator solenoid under the hood has to be fused (Mine had no protection.) and routed to the DC-to-DC charger. The solar panel was also routed to the DC-to-DC charger, per its instructions. The output of the DC-to-DC charger was fused and routed back to the new batteries. Obviously, the grounds have to be connected to a common chassis point.

The schematic is attached. Apologies for not CADing this drawing.

I paid about $500 (pre-tariffs - don't get me started) for all the parts to do it and took about one day, with much backside scratching on cable routing and component mounting.

The job takes some electrical skills, as several heavy cables are required and you’ll have to install connectors with a cable crimp tool for larger wires; I used an impact one for about $15. I’m an electrical engineer and had no problems, but I’d grab a geek to help, if you’re not versed in this. There are several pitfalls possible, and one could be hurt if done improperly.

Note that you will defeat the emergency start feature that bridges chassis and house batteries. I carry a jump-start pack for emergency starts.