I purchased the new two stage PD charger for two new Lion Energy UT 1300 lithium batteries. I also bought a Renogy DC to DC converter to protect the chassis battery. I have read that the PD can be installed as an auxiliary charger keeping the WFCO 8955 but I can’t find that information again. I have an outside outlet that I could extend inside to plug the charger in. But I’m unsure of the wiring from the WFCO. Seems I would need to connect the charging side to the batteries but keep the converter side connected to 12v load. Apparently it’s safer to run existing 12v through the WFCO at standard voltage instead of feeding 14.6v. The batteries are not in yet so I can’t experiment until they are delivered.

Get rid of the WFCO. The new charger is rated at 60A so place it as close to the batteries as possible with adequate wiring fused as needed based on the distance. This is the primary consideration, then wire in 120V as needed. Extremely doubtful that the wiring from the WFCO is adequate for the new charger.Suggestion: Research and understand wiring loss. At 14.6V and 60A inadequate wiring can easily result in excessive voltage drop. And this is directly related to the wire gauge size and distance.

EMD360, every RV we've owned has had the output of the converter, the input to the 12vdc fuse panel (located in the power center), and the batteries, all paralleled together. They are/were not isolated. If there's an inverter or dc to dc charger, they will also be paralleled with the batteries, too.A bit of debate whether 14.6v does any long-term harm to some 12vdc appliances. It will require a bit of work to isolate the 14.6v lithium charger voltage from the 12vdc panel. Not sure it's worth the hassle.

The new deck mount goes on the battery bank and the existing wires from the battery bank to the DC fuse panel stay as is. You can leave the "lower portion" converter part of the WFCO in place and just not use it.The DC-DC output also goes on the battery bank, as does any solar controller's output.You might need a positive buss bar to hold all the wires and just one fat wire from that to the battery. All the neg wires go to the shunt for your battery monitor including the wire that goes from the frame to the neg battery post now--it will go to the shunt and only one fat wire then goes from the shunt to the battery neg. If the shunt can't hold all those neg wires, then you need a neg buss for them and then a wire from it to the shunt and another from the shunt to the battery neg.(Of course you will have a monitor now to keep track of your new batts)The new two stage drops to 13.x once the batts are full? so no worries about long time 14.6.

So the recommendation is to just replace the WFCO charger with this one? I bought it because it does drop voltage after the batteries are charged. But it puts out 14.6 I believe on the converter side. Maybe not now that it’s a two stage. Might have to measure. If the existing negatives can be left alone then the new positive can wire to the old distribution system? If I wire this to the WFCO seems I would not need the plug I would cut it off and wire to the 120v side right? PD recommends this charger to replace WFCO8955 and I believe the wiring is adequate. Don’t have room in the battery compartment for this device but I could run a larger wire to the batteries. The existing wire just runs under the coach. It’s only a few feet away from the end of the bed to the stair battery case. I have to ground this charger separately anyway. I thought I’d put in a bus bar for negative and a fuse on the positive side. I was debating the fancy battery monitor. Will probably get it though. I just like these toys too much. I would like to see the wiring by someone who kept the WFCO charger though.

The two stage PD 14.6v lithium converter/charger should automatically drop down to a 13.6v - 13.8v float after a few hours of charge time (time varies due to SOC). Not sure if the PD Charge Wizard works on the new 2-stage PD lithium chargers. If they do, you have the option to manually force it down to the lower float voltage with the Charge Wizard.As for proper wire/cable size. What will be/is the length of the wire/cable run from the converter(s), dc to dc charger, etc. to the batteries? Here is an online Voltage Drop Calculator you can use that might be helpful (click on the Estimated Resistance tab). Ideally, you should strive for a 2-3% voltage drop under max load.

PD 9100 AL converter/charger. | Good Sam Community

EMD360
Explorer
May 08, 2021
Yes it sounds like disconnecting is the best option for the WFCO I think this has answered my questions. By the way the PD 9100 uses a 15 amp breaker but of course can use a 20 too.
BFL13
Explorer II
May 08, 2021
CA Traveler wrote:
OK 4' of 6ga wire, or 8ga with a little more voltage drop to the battery.

Plan on 8A AC draw and if an existing circuit can supply 8A then use it, otherwise install a new circuit and CB. I would not cut the AC cord for possible warranty considerations. Instead install a junction box or use a extension cord and cut it's male plug off.

The 60 amper will pull more like 11 amps at 120v. (PF 0.7 )
EMD360
Explorer
May 08, 2021
I can’t find the stamp on the existing wiring. I didn’t want to disconnect and peel off the protective wrap. It appears to be relatively robust. Here it is compared to #2. I probably have enough #2 to replace existing.
EMD360
Explorer
May 20, 2021
I need a bit more advice on this topic. I disconnected the WFCO charger and wired an extension cord end to the 120 volt side of the distribution panel. The converter shares a 15 amp breaker with the refrigerator. I used the same breaker for the new converter. I cut a hole in the panel and mounted the PD 9100 under the refrigerator and will plug the power cable to the WFCO 120v extension cord plug. The idea was to run the charger battery cables a short distance to the batteries. I have 3’ #2 cables for this. The wires from the new converter are run back to the DC side in the distribution box. This is the same way the old converter was connected.
My question is about attaching a wire set from the PD 9100 directly to the batteries and another set to the DC distribution panel at the same time. Does the existing distribution panel still have wires to the batteries that would have be used for charging?

I would be using both terminals from the Pd9100

The positive wire to the DC board from the batteries appears to be this wire on the breaker.
Labeled triangle 4-J. I believe this is the black positive on the bottom of the DC board.

The confusing part for me is the original converter had just one set of wires to the dc board and it’s not clear to me how the batteries were attached to charge.
Hope someone can clear this up for me. Tell me if the two sets of wires are correct.
BFL13
Explorer II
May 20, 2021
The WFCO had wires to the DC panel and the battery has wires to the panel. Either can run the Dc circuits on that panel and the WFCO charges the batteries down the same wires that the battery has going to the panel. Those wires (neg mostly frame is common) are a two- way street.

The new converter just needs wires to the battery. It will supply the DC panel up the same wires the battery uses to the supply the panel. The only diff is if the battery is removed, to run the panel from the new converter you will need to join the wire lugs together that were on the battery posts with vice grip pliers or something.
EMD360
Explorer
May 20, 2021
Thanks so much. No wires from the pd9100 to the DC panel just uses the same wires from the battery. These are small gauge but I guess not much power is needed at the dc panel.
If the batteries were ever removed the circuit would have to be closed between the positive and negative battery wires.
I had plenty of #2 wire but it does not fit in the pd9100. I guess they call for #4 so even better that the charger is closer to the batteries.
I’m still a bit confused by the wiring from the batteries to the panel. I think I have figured out the two disconnect switches though. One triggers when the starter is on and charges the batteries from the chassis. (solenoid) The other sends a start voltage to the generator if the starter is off it comes from the batteries if on from the chassis.
I was thinking one way street so knowing the wires are two way makes a big difference.
BFL13
Explorer II
May 20, 2021
You can still use the #2 if you use a step down connection to the PD. A short length of #4 or #6 will work or you can get those special step down lugs. The #4 might not quite fit in a set-screw hole, but you can shave some strands. Better to have proper lugs than set-screw on strands, which tend to slip out, hard to screw down on.

The short length of wire as an adapter is a "pigtail" will not choke off amps, being so short.
CA_Traveler
Explorer III
May 20, 2021
Best to use #2 and an adapter for the PD unit - ie minimize wiring loss. Directly to the battery both + and - with a fuse or CB on the plus cable near the battery.
EMD360
Explorer
May 20, 2021
I did not know these existed. Perfect.
BFL13
Explorer II
May 21, 2021
Good find! Here is how I had to rig a "strain relief" for stranded in set-screw terminals where there was heavy wire that would pull them out.

That was for using the converter a portable charger. Your set-up should be ok unless the #2 is that silky, millions of strands stuff that won't stay in a set-screw hole. In that case consider some sort of strain relief with those adapters.