Looking For Direct Replacement For WFCO9855 Converter Charger

Updated 06/08/2026 | Published 05/26/2026

Question:

Good evening. I have a 2018 Airstream Flying Cloud 30ft with the stock WFCO9855 converter/charger. I recently replaced my two AGM batteries with a single 320Ah LiTime lithium battery. What converter would you recommend to maintain the same spacing in the enclosure? I would like to keep in the 55A range, and am most concerned about having plug and play wiring, and the same or smaller footprint. I also have a 50A DC-DC charger installed and run to the truck alternator, so in most cases will be pulling in to camp with a pretty full if not full battery. Thanks for any help!

asked by: Stephen S

Expert Reply:

Hey Stephen, thanks for reaching out. We do have a great converter replacement for you that will work great with your Lithium batteries. I recommend the following:

- WFCO Auto-Detect RV Converter Charger - Deck Mount - 12V - 55 Amp # WF38FR

This is a direct replacement for your WFCO9855 so it'll fit in the exact same space in your enclosure. It has auto detect which allows it to automatically recognize lithium batteries and provide them with a full charge.

expert reply by: Jesse M

WFCO Auto-Detect RV Converter Charger - Deck Mount - 12V - 55 Amp
(click to enlarge)

Steve N.

6/2/2026

The WFCO 9855 AD is a nearly identical sized converter to the WFCO9855. I made the swap and found the most difficult part of the job was removing the power panel, which turned out to be super simple. The wiring was the same as the stock converter. Unplug the old one, disconnect the 6 GA wires, reconnect to the new AD converter, plug it into the back of the power panel, screw it down to the floor, reinstall the power panel and you're done. 20 minute job, tops.

Jesse M.

6/8/2026

@SteveN Thanks for sharing that, Steve! It’s great to hear the WFCO 9855AD was such a straightforward replacement for the WFCO9855. Real-world details like the matching wiring, plug-in connection, and nearly identical size are exactly the kind of information that helps others feel confident tackling the swap themselves.

Gene W.

6/2/2026

I recently upgraded to the WFCO 9855AD. It was very easy to swap the old for the new and I have had no issues with it. I know that there are some who have issues with the auto detect function, but there is a very good video on YouTube put out by the National RV Training Academy that explains how it works and how to set it up. There are no switches or jumpers that need to be set, you just need to make sure that the Lithium battery is below 50% charged so that the unit will go thru a complete charging cycle. Highly recommend watching the video. The only concern I had in ordering this was the photo on the web site showed that this came with a different type of plug than the standard residential three prong. After talking with Ashley E. in customer service, I did order it and am happy to say that it does have the standard three prong plug.

Steve E.

6/2/2026

I did exactly what you are doing—upfront 320A 12V Lithium battery. I went with the same recommended WFCO Auto Charger and easy peazy. 100%swap out and working great for my 30 foot towable trailer. I’ve been on 2 trips over 3000 miles and the AD converter is working perfectly.

Jesse M.

6/8/2026

@GeneW Thanks for sharing that, Gene! It’s great to hear the WFCO 9855AD was an easy swap and has been working well for you. I also appreciate you pointing out the National RV Training Academy video and the standard three-prong plug, those are both helpful details that should clear up a lot of common questions for other RV owners considering the upgrade.