Getting the inverter correct!

[HarryWiggs]

A bit frustrated: I'm no idiot--well, not a BIG one!--but this has me stumped.

So, my 2016 Cedar Creek 5th wheel had an inoperative inverter: it was a Magnasafe 1000W, where the on switch was inop. I replaced it with a WFCO WF5220 2000W inverter, which hooked up the existing wiring *exactly* the same as the Magnasafe did.

The WFCO inverter itself, works: what doesn't is anything on the trailer!

It has the standard 12V input, a sensing plug that tells the inverter if grid power is on, and a feed line up to a breaker, marked "INVERTER."

Far as I can sense out (DVOM) that circuit is the one that goes to the outlet, powering the sensor line, into the electrical panel. You can drop grid AC, and the inverter switches over (confirmed by DVOM), but nothing works, on the panel.

The feed line goes under the vehicle, above the belly pans, and likely out of sight, due to the tanks. I have traced...I think...and I see no transfer switch, or any other interruption in the feed line from the inverter...and no joy.

I ran a bypass line from the inverter, directly to the breaker for the fridge, and the fridge works. I could simply bypass the buried line to the panel, but that would mean, when grid power is on, that bypass line to the inverter (which doesn't put out any voltage when it senses grid power) would be hot to the inverter AC output...not sure that is adviseable.

Advice?

Harry

 

[bikendan]

Moved thread from the Appliances and Electronics sub-forum to the Electrical and Charging Systems sub-forum.

 

[TacomaJoe]

I'm not sure what your inverter powered. The old 1000W unit probably only powered a couple of things (refrigerator and TV?).

Your main power panel should have a circuit (inverter?) that feeds the sense input to the inverter. While you have shore power available the inverter should pass that power on to the output circuit and feed the refrigerator. When shore power is lost (sense input dead) the inverter will take the 12V battery power to make 120VAC for the refrigerator.

 

[HarryWiggs]

Therein lies the rub!

I do understand that, and the inverter responds as it should, when it loses the sense voltage: what doesn't happen is, anything in the Rv working off inverter voltage.

I have checked that the inverter does indeed with and send 110 to the supply line to the RV, but seems to not make it to the main panel.

 

[TacomaJoe]

I would take a step backwards, down to basics. Take the inverter out of the circuit and wire the input and output together (should be only 2 romex cables). On shore power, check to see if everything is working.

If the refrigerator is working, determine which circuit breaker is feeding the power to it. That same breaker should be providing to power to the inverter when it is connected.

The inverter gets wired between the 2 romex. The cable that is hot with shore power is the inverter input. The other (dead romex) to the refrigerator would go to the inverter output. The inverter as a built in transfer switch.

 

[Aussieguy]

is trailer 50 amp?
then inverter may have to go between power center breaker and the appliance /circuits you want to power

the inverter has a pass though (transfer switch) but using it on 50amp trailer can be more complex

in theory you can possible use dogbones etc if it is a 50 amp trailer and send power to all circuits


I would consult ... friend or a RV tech with good electrical experience
RV tech should be able to fix your setup for you within a hour... probably best money you'll spend.


JUST remember you can't power a LOT of stuff and you may have to power share

 

[HarryWiggs]

Further information on Inverter Blues!

I would take a step backwards, down to basics. Take the inverter out of the circuit and wire the input and output together (should be only 2 romex cables). On shore power, check to see if everything is working.

> I have done the steps that ensure the inverter is working properly. On shore power, it cycles off, and does not output 110V AC; with shore power removed, it then outputs 110V AC.

If the refrigerator is working, determine which circuit breaker is feeding the power to it. That same breaker should be providing to power to the inverter when it is connected.

> I've not traced that out, but can tell you the fridge works fine with shore power: what I find puzzling is, when I wired up the new inverter *exactly* the same as the old one, nothing works. There is AC out, going into the Rome, headed forward, but it's almost as if there's an open in the line, for at the main panel, I see no AC output.

The inverter gets wired between the 2 romex. The cable that is hot with shore power is the inverter input. The other (dead romex) to the refrigerator would go to the inverter output. The inverter as a built in transfer switch.

> I might need a specific wire diagram on that: I have jumped from the inverter, to the fridge breaker, and it operates. My question is, if I restring that jumper, hook it to the fridge breaker, when it's on short power, with that connection cause an issue? I think not, but want to make 100% sure.

Appreciate all your help!

Harry

Hope all that helps!

 

[TacomaJoe]

> I have done the steps that ensure the inverter is working properly. On shore power, it cycles off, and does not output 110V AC; with shore power removed, it then outputs 110V AC.

On shore power the inverter should continue to output 110 AC. This is the pass through function. When you cut shore power, the inverter will continue to output 110 AC (making it by using battery power).

Here's my simple sketch.


Shore power feeds the panel via main breaker. A branch breaker sends power to the inverter input and the inverter output continues on to the refrigerator.

That's my simple take on it. I can imagine a panel with an isolated bus. In that scheme the panel feeds the inverter from one bus, the inverter output comes back to the panel to feed another bus which then feeds the refrigerator.

 

[TacomaJoe]

Here's a sketch with an isolated bus.


This might be closer to what you have.

I can also wire a non pass-through inverter and then use a transfer switch or relay but let's not go there yet.