Two brands dominate the converters bolted into North American campers: WFCO and Progressive Dynamics, often shortened to PD. If you are going lithium, the first job is figuring out which family you have and whether it can charge the new bank properly.
The short answer is that some models are genuinely lithium ready, some can be coaxed close, and some really want a swap. Here is how to tell them apart without guessing.
Find your model first
Open the panel and read the sticker. WFCO units carry names like WF 8955 or the newer auto detect series. PD units show a model such as PD4645 along with a separate charge wizard designation.
Write down the full number before you do anything else. Everything downstream depends on it, and the difference between two similar looking part numbers can be the difference between a five minute setting and a converter swap. This is the same detective work described in the broader guide on whether your RV converter will charge lithium.
The WFCO story
Older WFCO 8800 and many 8900 series converters are three stage on paper, but their absorption boost only triggers when the battery voltage is quite low. A healthy lithium bank sits high and flat, so the WFCO often reads it as already full and never enters boost. The result is a lazy 13.6 volt trickle that leaves you at 85 percent.
Newer WFCO auto detect models solve this. They sample the battery and hold a higher voltage when they sense a pack that can take it. If your sticker says lithium compatible or auto detect, you may only need to confirm the setting.
Warning: Do not assume a three stage label means lithium ready. Plenty of three stage WFCO units still cap out at a lead acid float and quietly undercharge lithium for years.
The Progressive Dynamics story
PD converters pair with a charge wizard that steps through boost, normal, and storage voltages. Some PD models accept a lithium specific charge wizard, and Progressive Dynamics also sells a remote pendant that forces boost mode on demand.
The pendant trick works, but it is manual. You press it, the converter jumps to a higher voltage for a set time, and the bank charges more fully. For a lot of owners the better path is the dedicated PD lithium power center, which handles the right voltages automatically. The voltage targets behind all of this are covered in the right charge voltage for LiFePO4.
A troubleshooting walk through
Say your bank plateaus at 85 percent and the converter reads 13.6 volts. Work the problem in order.
- Confirm the model number and look up its published charge voltages.
- Measure the actual voltage at the battery terminals with a multimeter, not just the panel readout.
- If the reading sits near 13.6 volts under charge, the converter is stuck in a lead acid float.
- Check for a lithium jumper, an auto detect feature, or a compatible charge wizard.
- If none exist, plan a swap for a lithium charging section.
On a fifth wheel I worked on, the owner was sure the new batteries were faulty. The converter was a WFCO 8955 that never left float on the high resting voltage of the lithium pack. Swapping the removable charger module for the lithium version fixed it in about ten minutes, and the bank charged to full that afternoon.
Swap or setting?
If you have a modern auto detect WFCO or a PD unit with a lithium charge wizard, a setting or a compatible module gets you there. If you have an older single stage or a stubborn three stage unit, replacing the charging section is usually faster and more reliable than fighting it.
The good news is that both brands designed many of their power centers with a slide out charger section, so the swap is often just a few screws and three wires rather than a full rewire. The step by step for that job is in replacing an RV converter for lithium.
Match the converter to the chemistry and the rest of the system falls into place. A WFCO or PD that actually reaches 14.4 volts turns a frustrating 85 percent bank into the full capacity you paid for.
Measure at the battery, not the panel
The single most useful habit when diagnosing a WFCO or PD converter is to put a multimeter directly on the battery terminals while it charges. The panel readout can be optimistic, and voltage drop across long or thin wiring means the battery often sees less than the converter claims to send.
If the converter says it is boosting but the battery only reads 13.6 volts, you have found your problem, whether that is a lead acid profile or a voltage drop in the wiring. That one measurement saves hours of guessing and points you straight at the fix.
When a small charger is fine
Not every rig needs a big converter upgrade. If you mostly camp with hookups and rarely draw the bank down hard, even a modest lithium ready charger keeps you topped up overnight. The upgrade urgency rises the more you boondock and the faster you need to recharge on limited shore time.
Be honest about how you actually use the rig. A weekend camper with a single 100 amp hour battery and frequent hookups is in a very different situation from a full timer running a 400 amp hour bank off short generator sessions. Match the converter to your real pattern rather than the biggest number available, and you avoid both undercharging and paying for amps you will never use. The goal is simply a charger that reaches the right voltage and delivers enough current for the way you camp.
Keeping the old converter as a spare
If you do swap the charging section, hang onto the old one. A working lead acid converter is a handy spare, and if you ever sell the rig to someone running lead acid batteries, it goes right back in.
It is also worth writing down what you changed. A note taped inside the power center listing the new model, its charge voltages, and the date saves the next person, possibly future you, a frustrating diagnosis. RV wiring is often a mystery precisely because nobody documented the changes.
Where WFCO and PD leave you
Both brands make units that range from stubbornly lead acid to fully lithium ready, so the model number is everything. Read the sticker, look up the charge voltages, and measure at the battery to see what is really happening. If the converter reaches a proper lithium voltage, keep it. If it caps out at a lead acid float, a setting, a pendant, or a quick module swap gets you where you need to be. None of it is difficult once you know which of the two situations you are actually in.
