Electrical/Inverter Question

[shursnap]

I have a '96 Safari Class A RV and I'm trying to figure out why only part of my electrical works at a time except when the generator is running. When the generator is running everything seems to work, but the dining area light flickers every 10 seconds. When the 220V cord is plugged in about half of the electrical in the RV works. When that cord is unplugged and just using the inverter, the other half of the electrical works, but not most of the things that work when the 220V is plugged in. Since it all works with the generator, but not when plugged into 220V is it an inverter issue? If so, why doesn't the 220V bypass the inverter to run ALL of the 110V stuff in the RV? Any help would be GREATLY appreciated. Seems like the answer is probably obvious to someone who understands, but I'm not figuring it out.

 

[B52Bombardier1]

Are you certain that your vehicle requires 220 volts? That would be shocking to me . . . no pun intended. Most only require 30-50 amps at 120 volts.

Rick

 

[shursnap]

Are you certain that your vehicle requires 220 volts? That would be shocking to me . . . no pun intended. Most only require 30-50 amps at 120 volts.

Rick

It has a big 220V 50A plug on the end of the electrical cord that came with the RV. I did a little research and found where many do require 220V. They wouldn't wire a 4 prong 220v outlet with only 110v would they? It does have a 110V adapter that I can plug onto the end of the cord to plug into 110V, but still does the same thing when I use that and plug into 110V. I believe it's either/or if that's possible?

 

[shursnap]

I don't know if it makes any difference, but this is my inverter. It's a Heart Interface Freedom 20D and has 2 separate circuits.

 

[Dona40]

You can plug into 220 but that's just how the receptacles are wired. 120 on each leg. Your RV uses both legs but do not combine them to make 220. 120 on each leg. Sounds like one side of the electrical system is a non contact. Main breaker or the switch over box. I had an older RV once and the points in the switch box were burned. A little filling on them and worked fine again.

 

[AbdRahim]

 

[Rich W.]

So clearly there is a little confusion here about how RV electrical works. As stated above you most likely do not have 220v (or 240v which would be fhe case these days with two hots and a neutral). I suppose it‘s possible, but very unlikely. What you likely have is what is normal for 99% of RVs with a 50a service: two 120v legs each running about half the stuff the breaker box. This gives you two 6kw power sources to run a lot of 120v stuff. So if everything is wired correctly and some things don't work when plugged in to shore power, then you probably have a breaker issue.

The reason some things don’t work on the inverter is because you can only get so much power from your inverter (in this case 2kw worth), and then only run so long off your batteries. Regardless of your battery bank capacity, a 2kw inverter it wont run an air conditioner, and probably not a electric water heater or any other high demand 120v appliance. It will run a microwave, toaster, coffee maker etc, but not all at once. So an inverter is only wired to supply those things that it has the capacity to run, such as 120v outlets, a converter, and a microwave.

I dont know how advanced your electrical system is, or if your inverter is OE or aftermarket (more likely) or how big your battery bank is, so its hard to say with any certainty what you can expect from the it. But with a 50a service I’m assuming it has at least two air conditioners, and maybe some ofher high demand stuff.

The way to figure it all out is to open up the breaker box and see how it was wired from the factory, ie: what is powered by which leg, and what is powered by the inverter. Then if you have stuff that isnt working, you know where to look for the problem.

 

[Rich W.]

Rereading your original post, I would say your generator is powering things properly, your inverter is powering the items intended to run off that part of the system, and one leg of your shore power isn’t functioning, whether that is in the power source, plug, cable, transfer switch (likely as stated above), or in the breaker box.

So those are the things to check starting with your 50a outlet, and then working up the line until you find the fault. Because everything works on the genny, I’d concentrate on the shore power source, and the connections on both ends of the shore cord, including the transfer switch.

The flickering dining area light is probably a separate issue - most likely a bad connection, and not part of the main issue of half the 120v stuff not working on shore power, but simply there to distract you and make this seem more complicated than it is - a typical situation with RV electrical issues.
.

 

[shursnap]

So clearly there is a little confusion here about how RV electrical works. As stated above you most likely do not have 220v (or 240v which would be fhe case these days with two hots and a neutral). I suppose it‘s possible, but very unlikely. What you likely have is what is normal for 99% of RVs with a 50a service: two 120v legs each running about half the stuff the breaker box. This gives you two 6kw power sources to run a lot of 120v stuff. So if everything is wired correctly and some things don't work when plugged in to shore power, then you probably have a breaker issue.

The reason some things don’t work on the inverter is because you can only get so much power from your inverter (in this case 2kw worth), and then only run so long off your batteries. Regardless of your battery bank capacity, a 2kw inverter it wont run an air conditioner, and probably not a electric water heater or any other high demand 120v appliance. It will run a microwave, toaster, coffee maker etc, but not all at once. So an inverter is only wired to supply those things that it has the capacity to run, such as 120v outlets, a converter, and a microwave.

I dont know how advanced your electrical system is, or if your inverter is OE or aftermarket (more likely) or how big your battery bank is, so its hard to say with any certainty what you can expect from the it. But with a 50a service I’m assuming it has at least two air conditioners, and maybe some ofher high demand stuff.

The way to figure it all out is to open up the breaker box and see how it was wired from the factory, ie: what is powered by which leg, and what is powered by the inverter. Then if you have stuff that isnt working, you know where to look for the problem.

So are you saying that the shore power is 220V at the outlet, but the RV splits it into 110V per leg and powers the two circuits that way? If so that makes more sense to me that the problem might be in the transfer switch, or a bad connection. That also makes sense that the things powered by the inverter would be limited so as not to overdraw on the batteries. The generator then must bypass the transfer switch since everything works when it's running? That would also prove that the breakers and everything else are okay, so the problem has to be between the outlet and wherever the shore power ties into the circuits, right? (transfer switch, or a connection issue), or am I offbase? I'll definitely do some metering and check connections.

 

[shursnap]

Rereading your original post, I would say your generator is powering things properly, your inverter is powering the items intended to run off that part of the system, and one leg of your shore power isn’t functioning, whether that is in the power source, plug, cable, transfer switch (likely as stated above), or in the breaker box.

So those are the things to check starting with your 50a outlet, and then working up the line until you find the fault. Because everything works on the genny, I’d concentrate on the shore power source, and the connections on both ends of the shore cord, including the transfer switch.

The flickering dining area light is probably a separate issue - most likely a bad connection, and not part of the main issue of half the 120v stuff not working on shore power, but simply there to distract you and make this seem more complicated than it is - a typical situation with RV electrical issues.
.

Makes sense. Then does the generator bypass the transfer switch when powering the RV? If so could that mean that the issue is likely between the outlet and the output of the transfer switch?

 

[Rich W.]

The generator goes through the transfer switch but has it’s own input contacts (it switches between shore and generator power), so the issue is likely the transfer switch contacts for the shore cord. Either that or on the cord, plug or power source.

 

[shursnap]

The generator goes through the transfer switch but has it’s own input contacts (it switches between shore and generator power), so the issue is likely the transfer switch contacts for the shore cord. Either that or on the cord, plug or power source.

Thank you! I'll start at the outlet and see what I can find. I'm hopeful. Just to confirm, am I correct in assuming that the outlet should be a standard 220V 50 amp service?

 

[Rich W.]

It’s two hots, a neutral and a ground. Normally two hots and a neutral would be all you need for 240v residentail stuff like a welder, water heater, dryer, table saw, compressor, etc. But for RVs we have to have both a neutral and ground. So your outlet should test out accordingly.

Here are some useful pics:

 

[Rich W.]

Definitely start at the power source, but as Dona40 reminded us, the problem is probably in the shore cord connections or contacts of the transfer switch. But it could also be in the source, plug, or cord.

 

[shursnap]

It’s two hots, a neutral and a ground. Normally two hots and a neutral would be all you need for 240v residentail stuff like a welder, water heater, dryer, table saw, compressor, etc. But for RVs we have to have both a neutral and ground. So your outlet should test out accordingly.

Here are some useful pics:
View attachment 15531View attachment 15532View attachment 15533

This is VERY helpful! Thank you SO much for all the good info. It was raining today so I couldn't test, but hope to start testing/checking tomorrow. I'll let you know what I find out.

 

[Rich W.]

I was going to get into the possible open neutral condition that may be at your power source and the cause of your issues, but found this article and it explains everything much better than I can. Good rainy day reading:

Open Neutral

www.myrv.us

So read this start to finish, then check everything in your power source if its at your own property, or if you are in a camp ground, ask the owners. I have a Precision Circiuts EMS and always thought that was enough, but before this trip I bought a Progressive Industries surge protector Progressive Industries SSP-50XL form Amazon for $109 (now they are $132) and while I don’t worry much about power surges, it also tests the outlet and verifys that it is delivering power properly (although not under load) and tells you the pedestal is good (or not) before you plug in. Note the first item on the “product features” list is open neutral and ground.

My son the all-knowing genius/inventor (police detective by profession) and sine-qua-non solar and lithium guru, would say these are a waste of money, but its not his coach, and I am glad I spent the $109 to have a little peace of mind.

 

[AbdRahim]

This forum is like going to college again. Thanks Rich W.
It would be horrible to have to test each pedestal with such a high load at each campground. On the other hand, the extra time could save a lot of headache and expense.

iIs there an adapter that goes from 50A to two plugs - one on each leg?

 

[Rich W.]

This forum is like going to college again. Thanks Rich W.
It would be horrible to have to test each pedestal with such a high load at each campground. On the other hand, the extra time could save a lot of headache and expense.

iIs there an adapter that goes from 50A to two plugs - one on each leg?

I’ve never seen an adapter like that but you could make one easy enough. Not sure what you’d normally use it for. It could be used if one leg of a 50a service was bad, although if that were the case I wouldn’t even try to use the outlet. 50 to 30 amp adapters just use one hot, the neutral and the ground from the 50a plug to power the 30a outlet.

 

[Rich W.]

This forum is like going to college again. Thanks Rich W.
It would be horrible to have to test each pedestal with such a high load at each campground. On the other hand, the extra time could save a lot of headache and expense.

iIs there an adapter that goes from 50A to two plugs - one on each leg?

Ok so they do exist as shown below. The first one (yellow) could be bad news because you could easily overload the 20amp outlet long before the 50a breaker would trip. The second one (orange) has built in breakers so it would be ok to use in about any application. Still not sure why you would need one, but there it is, available from Amazon (AC Works) for $65. Maybe to power a big deep fryer outside, or for boiling crabs? I guess any cooking or anything else you wanted to do electrically outside the coach.

 

[jagpot]

Try resetting your Inverter. I have 2 switches. Had this problem in a previous coach and that fixed the issue.