Replacing WFCO 8735 with Progressive Dynamics

[BarabooBob]

While reading this forum about the WFCO 8735 being broken when new, I doubted this claim. I have a new Viking 17RD with a WFCO 8735 installed.

I unintentionally let the battery run down to 12.0 volts due to forgetting to plug in after a recent trip and decided to test the WFCO output. I plugged the camper into a 30 amp outlet without using an extension cord to minimize variables and tested the voltage that was reaching the battery. My digital voltmeter got a reading of 13.6 volts and it never went any higher. The owners manual claims 14.4 volts. The next day it still read 13.6 volts.

I guess that people were correct in stating that the WFCO converters are broke when new and it is time to order a new Progressive Dynamics power center. Anyone know if a 4045KV would work better than a 4135KV? I can't see any reason to get the current converter replaced under warranty because they would just install another junk WFCO.

I installed a Progressive Dynamic 9245 in my old Toyota RV and it always charged the batteries up very quickly. I had a digital voltmeter installed and it would run up to 14.4 and then drop off after a few hours.

[MR.M]

never had issues with WFCO converters . replaced many progressive converters along with a few WFCO and i would not have a problem using either . according to some here 12v is still a well charged battery . lol i get 14.4 volts out of my 4 years old WFCO when the batteries are down

[ScottBrownstein]

WFCOs have two known issues. One is that some of them refuse to go into boost mode (>13.6) for very long or at all, and second is that some of them won't drop down to float and end up boiling electrolyte. Obviously this is not necessarily all WFCOs, but you seldom hear these complaints about PD converters.

You measured 13.6. Where did you do that? At the battery or at the converter output. On my rig, the cables between the two are very long and result in at least a 1 volt drop when charging with heavy current.

[pgandw]

Baraboo Bob

Your experience is the same as mine - with 2 different Rockwood/Flagstaff A-frames. Both purchased new, both with the WFCO 8735P converter. Neither ever put out a voltage other than 13.6V. Never went to 14.4V, never went to 13.2V.

The first one I replaced with a PD4135, which is listed a drop-in replacement. The PD 4135 is slightly smaller in width, but the trim panel may/may not cover the gap. I added some reinforcement behind the Forest River "plywood". I also added a bus bar because all the DC negative/ground wires were joined in a series of wire nuts. My write up can be found at Replacing my A-frame WFCO Converter in the A-frame forum.

My 2019 Flagstaff T21TBHW A-frame will also not go into float. I already ordered the PD 4135, and hope to do the replacement this weekend. As on the A122, I will install a voltmeter and switch for the voltmeter just inside the door so I can quickly check on what the converter and batteries are doing. I am also adding a switch to the stereo so I can rid of the parasitic draw and the annoying speaker "pop" whenever I plug in or use the battery disconnect.

The PD 4135 replaces the WFCO 8735 completely, so it's a matter of transferring the wires, circuit breakers, and fuses from one box to the other. Even though my GC-2 batteries could tolerate a higher charge rate than 30-35 amps, I don't have a generator so the time to recharge is not as critical (it's maybe a 30 minute difference out of at least 6 hours if I'm down to 50% on the batteries).

Other advantages of the 4135 are that the fan is much quieter than the 8735 (only heard the 8735 fan once in the year it was installed), and it will charge at bulk rate up to about 90% SOC (much faster than a working 8735).

hope this helps in your decision
Fred W
then 2014 Rockwood A122 A-frame
now 2019 Flagstaff T21TBHW A-frame
camping Colorado and adjacent states one weekend at a time

[TitanMike]

A good part of the problem with any converter not staying in bulk mode very long is the length and gauge of the wire between battery and converter. If the converter is more than 4-5 feet from the battery there is enough line loss that the voltage at the converter climbs to the point it switches to the lower charge voltage long before the battery is ready.

Two solutions.

Install a much larger wire than the #8 awg wire that seems to be standard on most FR products to at least a #4 awg.

Second choice would be to install a PD9200 series converter that is self contained (fully enclosed) and has a regular plug on the power cord. Locate it as close to the battery as possible, connecting it to the battery with a #6 or #4 gauge wire and just leave the factory wiring in place to the power distribution panel. Plug the converter into a nearby electrical receptacle or run the converter 120v wire from breaker to a new receptacle installed near the new converter location. If you use existing wiring be aware that that circuit will probably be unhappy if you plug in a heater on a cold night, especially if charging battery bank at full rate. Extending wiring for converter from old to new location is the best solution.

Voltage drop will be nominal and the various charge cycles will function as designed.

[pgandw]

I started replacing my WFCO 8735P on Sunday with the PD 4135. In removing the covers and mounting screws for the WFCO, I found two of the cover mounting screws stripped, the threaded receptacles for the screws were missing. I also found a #10 white wire running to chassis ground in the AC section of the WFCO. I believe it's the negative (ground) wire from the battery leads of the WFCO converter. I have no idea why it was in the AC section. But I didn't find any other DC negative coming out of the converter.

I saw no easy way to access and replace the converter section by itself. The PD4135 replaces the panel and the converter in one package. The PD converter module can be replaced by itself should it ever prove necessary.

Physically, the PD is about 3/4" narrower than the WFCO, and about 1/2" shorter, too. I added some 1/2" x 1/2" at the bottom and 3/4" x 3/4" pieces on the back side of the veneer plywood to frame the hole a little more accurately. I also have 3/4" wide trim to cover the gap in the veneer on the sides of the panel/converter.

Wiring wise, I was surprised to see the converter and AC portion (fridge receptacle) of the fridge were put on the same circuit breaker. Turned out this was listed as an available branch circuit in the WFCO diagrams. I replaced the single 15A breaker that powered the microwave with a dual 15A breaker, and moved the fridge AC (receptacle) to its own breaker.

I replaced the massive wire nut cluster used for DC grounds (negative) with a ground bus used in circuit breaker panels mounted on the dinette seat cross piece. WFCO has 6 different color wires for the DC circuits, and FR had a sticker with the fuse size and purpose of each color wire (not totally accurate on the wire's purpose). I cut the WFCO colored wires at the halfway point, so I had the color reference where it connected to FR wiring, and left the WFCO usable for anybody that wants to take it off my hands.

One by one, connected the DC circuits with waterproof butt connectors using the WFCO color code as a guide. For circuits that have more than one wire coming to the panel, I added a small bus bar rather than repeat the WFCO wire nut mess.

In the A-frame world, the converter/panel is located about 4ft from the battery, with about 8ft of wire. With the converter rated at 35 amps, Titan Mike's concern about the smaller wire sizes (#8, #10) are not as much of an issue as on larger campers. Before I finish the project, I will tie the 2 chassis grounds (one under the converter, and one near the battery box) together with some #10 wire just to reduce voltage losses at the ground points. The main reason for not going larger is that I don't have crimps or strippers for more than 10 gauge.

To finish out the project, I'm adding a small digital voltmeter with on/off switch by the door. This way, I can tell what the converter/batteries are doing at any given time without removing a cover to read voltage. I'm also adding an on/off switch for the stereo, which is annoyingly on at all times.

Fred W
2019 Flagstaff T21TBHW A-Frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time

[latner]

Originally Posted by TitanMike

A good part of the problem with any converter not staying in bulk mode very long is the length and gauge of the wire between battery and converter. If the converter is more than 4-5 feet from the battery there is enough line loss that the voltage at the converter climbs to the point it switches to the lower charge voltage long before the battery is ready.

Two solutions.

Install a much larger wire than the #8 awg wire that seems to be standard on most FR products to at least a #4 awg.

Second choice would be to install a PD9200 series converter that is self contained (fully enclosed) and has a regular plug on the power cord. Locate it as close to the battery as possible, connecting it to the battery with a #6 or #4 gauge wire and just leave the factory wiring in place to the power distribution panel. Plug the converter into a nearby electrical receptacle or run the converter 120v wire from breaker to a new receptacle installed near the new converter location. If you use existing wiring be aware that that circuit will probably be unhappy if you plug in a heater on a cold night, especially if charging battery bank at full rate. Extending wiring for converter from old to new location is the best solution.

Voltage drop will be nominal and the various charge cycles will function as
designed.

3rd solution:

Good, fully automatic, portable battery charger.

Since I didn't want to go thru the aggravation and cost of upgrading wiring/converter, this works real nice for me.

I should add that most of my camping is off grid, using a genny to recharge dual 6 volts.