Solution to Replace WFCO 8735P to Charge Lithium Batteries

Question

Question:

I have just installed a 200Amp hour lithium battery in our 2019 Aliner. I need to upgrade the WFCO 8735P convertor the a model that will charge Lithium batteries. I am considering the Progressive Dynamics PD4135K. Will this unit charge the battery from the tow vehicle? If not what are my options? Is there a power control center that has this ability incorporated into it? By the way, I also charge the battery using solar. Thanks for your help

asked by: Russ S

0

Expert Reply:

I have a solution for you because as you know what you have now cannot charge Lithium batteries. You will need the Progressive Dynamics # PD4135K which is designed to replace your WF-8735P and is compatible with Lithium batteries. When this is connected to your tow vehicle power source it will help charge the batteries. This will not interfere with your solar charging setup either.

expert reply by: Jameson C

0

Steven

1/25/2025

You said the 8735 p doesn’t charge lithium batteries but that manufacturer says it will. I would like a straight answer on this as I am consider lithium batteries as a change.

Jameson C.

1/27/2025

@Steven At one point it did not but in recent years they have been updating the part numbers to have lithium profiles since the are getting more popular.

Sean

4/10/2025

@Steven - I have the WF-8735P in my trailer running a single 80amp deep cycle AGM and 200 watts solar. I recently bought two 100amp lithium batteries for it before knowing that the converter could be an issue. My 8735P converter manufacture date is Jan 2020. I spoke with a tech at Western WFCO yesterday. I can only relay what I was told in the phone call but what he told me was..... A- He said it would charge my Lith batt's but only up to 70-80% while plugged to 110. B- My solar would charge above the 70-80% though. C- 200 amp was the upper limit of the converters ability. D- He also said that unlike AGM batteries, Lith batt's can be drawn down further than the AGM 50% recommendation and that they have a built in range safety feature. Keep in mind, I'm only stating what I understood from the the phone call. @ Jameson and I forgot to ask about about vehicle charging. I plan to eventually swap out my converter but might do some trials at the house before our next trip. Most our trips are just 2-3 nights, light power use anyways. @jamesonc Please correct me if I am wrong in any of this. Thanks in advance.

Jameson C.

4/10/2025

@Sean did he say the reason it would charge past a certain point because it doesn't have the lithium profile? That would check out but figured I would ask. It is true lithium batteries can be ran down further and they will work super strong as well as will bounce back better. They really are great batteries.

See All (9) Replies to Steven ∨

Lee

7/17/2025

The converter has nothing to do with the tow vehicle. It is a 120V to 12V converter for running the camper and charging the battery. The reason the WFCO 8735P won't charge Lithium is because the lithium discharge voltage profile means the lithium battery voltage will be well above 12.8 v even when discharged, and the 8735P, thinking its a lead battery, will immediately go to float at 13.5 which will not charge lithium.

Jameson C.

7/17/2025

@Lee Yes this is correct.

Answer 1

Hey Mike, welcome back! Thanks for all of the info you listed from your Grand Design. Based on that and fact you have 5,200 lb axles the correct bearing kit would be the part #BK3-300 which comes with the correct bearings, races, seal, and a cotter…

view full answer...

Answer 2

I spoke with Progressive Dynamics and they informed me that you cannot replace just the converter section and you would need a new panel, the Progressive Dynamics Mighty Mini AC/DC Panel and Converter/Smart Charger part #PD4045KA. The Progressive…

view full answer...

Answer 3

Hey Nancy, yes the WFCO Auto Detect RV Converter and AC/DC Distribution Panel #WF96FR that you referenced is the correct replacement for your WF8735P that you have now and is compatible with lithium batteries like you need as well. This is same shape…

view full answer...

Answer 4

WF-8735P is a 35-amp panel model. To upgrade to a lithium ready system you will need the Progressive Dynamics #PD4135K Converter/Smart Charger rated for 35-Amp. this system includes a high voltage output to provide full, quick charge for your lithium…

view full answer...

Answer 5

Hello Vernon, Great question. I actually reached out to Coleman-Mach to make sure. Based on what they told me, if your Keystone Alpine 3220RL was equipped with the In-Command system and factory prepped for a third AC, the Coleman-Mach Mach-C Everest…

view full answer...

Answer 6

Hey Mark, the height of the etrailer Electric Trailer Jack #e23ZV that you referenced above the mounting plate is 20 inches. This is about the shortest dimension you'll get from a jack like this. Would that be enough clearance?

view full answer...

Answer 7

Hey John! Yes, a 65A converter/charger like the PowerMax #PM64VR will work well with this setup. Your 30A shore service can easily handle it, and 4 AWG over a 12' run is a solid choice to keep voltage drop low. Just be sure to install a properly…

view full answer...

Answer 8

Hello Ingrid, thanks for reaching out, and congrats on the new camper! The Velit 2000R Mini AC #VE69QV can only be installed horizontally. It can be installed on sloped roofs, but it must be less than 15 degrees. It cannot be installed vertically on…

view full answer...

Answer 9

Hello Pete; I'm sorry to say there are no replacement converter sections available for the 4135. Have you checked to see if you have the lithium switch on yourse? See the attached pictures which show the location of the switch. If you do not have…

view full answer...

Answer 10

Hey Lance, thanks for the information! I don't have just a lithium compatible replacement converter for your WFCO 8735. The best solution I have is the Progressive Dynamics Mini Panel item #PD4045KA. This 45 amp panel will replace everything you…

view full answer...

Answer 11

We have had this come up in the past and Firestone has confirmed that yes, the: -Firestone Coil-to-Air-Spring Conversion Kit #F2595 can lower your truck when compressed to the minimum 5 PSI, however they do not specify how much lower the truck will…

view full answer...

Answer 12

Hey Christopher, thanks for reaching out! You might actually have a lithium setting on your current model that will allow it to work with a LifePO4 battery bank. If you check out the linked photo you'll see what I mean. If you aren't able to…

view full answer...

Solution to Replace WFCO 8735P to Charge Lithium Batteries

Continue Researching