WFCO AC/DC converter - disable charger

[Rob578]

First Post here so please be gentle.

I have a WFCO WF-8955pec in my Class C. I want to install an inverter and feed the output straight into the Panel. Is there a way to disable the battery charging component of the WFCO so it's not in the perpetual cycle of trying to charge the battery while being powered from the inverter?
I've looked at wiring diagrams and manuals but I haven't actually pulled it apart to see if there's a lead that I might be able to add a switch to.

I don't have room to add subpanels and split up loads so I'm going the easy route.

I'm sure this question has been asked a million times but I haven't seen any answers other than "just disable it"

Thanks for reading.

[twinboat]

Find the circuit breaker for it and switch it off. Sometimes the converter is on a breaker with something else. Remove the outer cover of the breakers and clip the black wire going to the converter. You can add a switch there.

[PS89]

As twinboat said, easiest is to simply turn off the circuit breaker to the converter.

Since I don't always remember stuff, I automated the process by adding a relay that, when the inverter is operating, it opens the normally closed contacts of a relay that is installed between the converter's AC input and its circuit breaker. Just automating the second half of twinboat's suggestion.

[Persistent]

Inverters can be installed in different ways.

1000 watt inverter
Small inverters are often connected directly to the battery and have 120 volt outlets on the device to power low current 120 volt devices.

2000 watt inverter
A 2000 watt inverter can be connected the same way. It can power one 120 volt heating or cooling device. The 120 volt output can also be connected to a sub-panel with branch breakers where 120 volt circuits can be connected. Of course you would not connect the WFCO to the sub-panel.

2000 watt inverter with transfer switch
A 2000 watt inverter with an internal or external transfer switch can be used. Connect using a sub-panel as described above. Also connect the input to the transfer switch to a branch breaker in the main circuit breaker panel. This will pass 120 volt shore power through to the sub-panel and disconnect the inverter.

Inverter/Chargers
These devices have an inverter, a charger, and a transfer switch built in. It will shut the charger "OFF" when shore power or generator power is not available.

3000 watt inverter or inverter/charger
These high capacity chargers may be installed with a sub-panel or they may be installed so all 120 volt circuits are supplied with inverter power. The built in charger is switched "OFF" when inverting from battery power.

A whole house system requires a new main breaker to protect the shore power wires. The old main breaker is connected to the inverter output.

[creativepart]

Imagine a day in the future when you sell that RV. This whole Converter circuit breaker routine will be real head scratcher and overall problem for anyone that owns the RV in the future.

I think it’s vastly better to have an electrician properly wire the new inverter into your electrical system not including the Converter. And while you are at it…unless you’re putting in a powerful inverter and lots of battery storage to have that wiring skip the A/C, water heater and microwave.

Factory inverter installs utilize an inverter sub panel with limited provisions for high load circuits that the inverter can’t handle.

[whybother]

If this is a proper inverter/charger with a built in transfer switch, then just remove the hot wire that leads to the converter to fully disable it. (There's a black wire that leads from one of the breakers to the built-in charger. Pull it, cap it, and add a able saying "converter disabled. see inverter/charger")

If this is just a plain inverter, then return it and get a proper inverter charger with built-in transfer switch, like the Victron 12/3000, and do it right from the start. (You could manually add a transfer switch, a contactor to enable the WFCO's charger when powering from shore, etc., but just... don't. And surely don't rely on manually turning off/on the charger when switching between inverter/shore.)

[Sunnyfalls]

Originally Posted by Rob578

First Post here so please be gentle.

I have a WFCO WF-8955pec in my Class C. I want to install an inverter and feed the output straight into the Panel. Is there a way to disable the battery charging component of the WFCO so it's not in the perpetual cycle of trying to charge the battery while being powered from the inverter?
I've looked at wiring diagrams and manuals but I haven't actually pulled it apart to see if there's a lead that I might be able to add a switch to.

I don't have room to add subpanels and split up loads so I'm going the easy route.

I'm sure this question has been asked a million times but I haven't seen any answers other than "just disable it"

Thanks for reading.

This is problematic but possible.

The battery is connected to both your DC distribution panel and your WFCO charger/converter. You will want to retain the connectivity between the battery and the DC distribution panel so you have 12VDC power when you don't have shore power.

The WFCO charger/converter is connected to your DC distribution panel so you have 12VDC power when connected to shore power without depleting the battery. So you will want to retain this connectivity too.

Using circuit breakers as switches is a bad approach as it wears them out prematurely. Finding a mechanical switch that can handle the DC amperage gets your into what is often used to disconnect a battery completely from the RV. We personally don't like mechanical switches or mechanical relays and instead use grossly amperage overrated solid state relays for long term reliability and to avoid long lengths of high amperage DC cable.

If I understand your goal, you simply want to use inverter power when you don't have shore power thereby avoiding the need of breaking up the inverter power and shore power on the AC distribution bus bar or having seperate AC distribution panels for each.

My suggestion would be to do what we did for our Renogy 3000 Watt inverter and 100AH LIFEPO4 battery. Just have the inverter power an independent and seperate 120VAC 20A circuit that you can use both with and without shore power. Bring both the inverter power and shore power into a standard 3-way 30A AC switch that then feeds this circuit. When you have shore power, toggle this switch to use the shore to power this circuit. When you don't have shore power, toggle this switch to use the inverter to power this circuit. If you have shore power, but you want even more power for some reason, toggle the switch to inverter power. We put our absorption refrigerator, microwave oven and toilet heated bidet seat on this circuit. All of our electrical receptacle outlets have green pilot lights, so it is obvious when we need to toggle this switch.

Using this approach and upgrading our trailer from 120VAC 30A to 120/240VAC 50A provides us with 2400 Watts capability when dry glamping and 14,400 Watts capability when we have shore power. When we have shore power, we use our electric (240VAC 6500 Watt)/propane tankless water heater, 240VAC 3500 induction cooktop and 120VAC 1500 Watt heater. This approach also avoids the need for expensive and failure prone transfer switches.

More photos and details of this Casita trailer modification and all our many other Casita trailer modifications may be found by Googling our below trailer name.

If any of this sounds complicated or confusing, hire an electrician.

Gayle & Bob
"Los Gatos Casita"

[Rob578]

Originally Posted by twinboat

Find the circuit breaker for it and switch it off. Sometimes the converter is on a breaker with something else. Remove the outer cover of the breakers and clip the black wire going to the converter. You can add a switch there.

The WFCO 8955pec does not have a breaker for the converter/charger AC input.

[Rob578]

Originally Posted by PS89

As twinboat said, easiest is to simply turn off the circuit breaker to the converter.

Since I don't always remember stuff, I automated the process by adding a relay that, when the inverter is operating, it opens the normally closed contacts of a relay that is installed between the converter's AC input and its circuit breaker. Just automating the second half of twinboat's suggestion.

The WFCO 8955pec does not have a circuit breaker for the AC input to the converter/charger.

[Rob578]

Originally Posted by Persistent

Inverters can be installed in different ways.

1000 watt inverter
Small inverters are often connected directly to the battery and have 120 volt outlets on the device to power low current 120 volt devices.

2000 watt inverter
A 2000 watt inverter can be connected the same way. It can power one 120 volt heating or cooling device. The 120 volt output can also be connected to a sub-panel with branch breakers where 120 volt circuits can be connected. Of course you would not connect the WFCO to the sub-panel.

2000 watt inverter with transfer switch
A 2000 watt inverter with an internal or external transfer switch can be used. Connect using a sub-panel as described above. Also connect the input to the transfer switch to a branch breaker in the main circuit breaker panel. This will pass 120 volt shore power through to the sub-panel and disconnect the inverter.

Inverter/Chargers
These devices have an inverter, a charger, and a transfer switch built in. It will shut the charger "OFF" when shore power or generator power is not available.

3000 watt inverter or inverter/charger
These high capacity chargers may be installed with a sub-panel or they may be installed so all 120 volt circuits are supplied with inverter power. The built in charger is switched "OFF" when inverting from battery power.

A whole house system requires a new main breaker to protect the shore power wires. The old main breaker is connected to the inverter output.

I appreciate your input, but I already have a plan for the inverter portion.

[Rob578]

Originally Posted by creativepart

Imagine a day in the future when you sell that RV. This whole Converter circuit breaker routine will be real head scratcher and overall problem for anyone that owns the RV in the future.

I think it’s vastly better to have an electrician properly wire the new inverter into your electrical system not including the Converter. And while you are at it…unless you’re putting in a powerful inverter and lots of battery storage to have that wiring skip the A/C, water heater and microwave.

Factory inverter installs utilize an inverter sub panel with limited provisions for high load circuits that the inverter can’t handle.

I appreciate your input but I'm a licensed electrical contractor. My plan is to automate this entire scheme so that my technology challenged wife can operate it by herself.

[PS89]

Originally Posted by Rob578

The WFCO 8955pec does not have a breaker for the converter/charger AC input.

It is the responsibility of the coach builder to install and connect the 120V circuit breakers for the branch circuits of which the converter is one.

If it didn't come with one, it is simple to add one.

[Bobby F]

Go to the back of the converter, find the incoming AC power leads, snip one, and run a line loop up to a wall-mounted indicator switch in the cabin, such that whenever you are running that converter, the red indicator light is lit.

That will stop the battery-charging-itself suicide loop.

[Rob578]

Originally Posted by whybother

If this is a proper inverter/charger with a built in transfer switch, then just remove the hot wire that leads to the converter to fully disable it. (There's a black wire that leads from one of the breakers to the built-in charger. Pull it, cap it, and add a able saying "converter disabled. see inverter/charger")

If this is just a plain inverter, then return it and get a proper inverter charger with built-in transfer switch, like the Victron 12/3000, and do it right from the start. (You could manually add a transfer switch, a contactor to enable the WFCO's charger when powering from shore, etc., but just... don't. And surely don't rely on manually turning off/on the charger when switching between inverter/shore.)

The WFCO converter is wired in parallel with the batteries and the wiring looks to be about a #4awg. If I take he converter out of the circuit then the 12v side is going to pull directly from the batteries and they will have to rely on Inverter's charger and Solar rather than the AC/DC converter source. I want to avoid that scenario.
I could take the WFCO converter out of the circuit and install a standalone AC/DC converter but I have very limited space and that seems to be adding needless complexity.
I intend to add a Victron Multiplus II for the inverter.