Replacement Converter for a WFCO 8735-AD
Updated 09/29/2025 | Published 09/01/2025
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Question:
I have a 2022 Grand Design 22RBE with a WFCO 8735-AD controller/convertor. I switched to a 300Ah LifePO4 battery and it will charge for only 5 minutes or so and stop. The installed soler panel seems to charge the battery fine. I also have two 100Ah LifePo4 batteries I use for separate power. The WFCO will not charge that either. I have tried every trick that they suggested and no improvement. So, I and thinking I will disable the Buit-in controller and install the PD 9360 for better charging. I have the space and the outlet, so it looks like an easy install. So, the question I have is on the wiring. There are red and white out of the DC side that look like they connect to the battery. Do those simply get disconnected from the built-in converter the back of the new deck-mount?
asked by: Benjamin L
Expert Reply:
Hey Ben. It definitely sounds like your converter/charger has gone out. The Progressive Dynamics 9300 Series RV Converter Charger item # PD79RR is definitely going to be the easiest way to replace it. There isn't a way to just replace the converter section of a WFCO 8735 so you'd have to swap out your entire panel with the Progressive Dynamics Mini Panel item # PD4045KA.
As far as installing the PD 9300 item # PD79RR, you'll need to contact an electrician or trace those wires back to their source to identify them. I don't know how a WFCO 8735-AD converter/charger is wired up. I would pay more attention to what terminals those wires are connected to. The installation instructions for item # PD79RR focus on positive and negative. I have attached a screenshot from them below and linked the entire instruction manual.
(click to enlarge)
Product Page this Question was Asked From
Progressive Dynamics 9300 Series RV Converter Charger - 12V - 60A
- RV Power Converter
- Converter Only
- No Battery Mode Switch
- 12V
- 60 Amps
- AGM
- Lead Acid
- Lithium
- Single-Stage Charge
- Progressive Dynamics
more information >
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Jerred H.
9/29/2025
Hey Ben, did you have a chance to trace the wires or consult an electrician for the installation of the new converter? I'm asking because your experience could help others facing similar issues with their RV setups.