Inverter Transfer Function

[Jon Wehrenberg]

Just a piece of information about the automatic switching (at least in my vintage Liberty).

The way it has been set up, AC power defaults to the best source. In the absence of CG or generator power the switch allows the inverter power to pass into the AC circuit breaker panel.

If CG power is connected to the coach the relay closes so CG goes to the panel. If the generator is running, even if hooked up to CG power the transfer defaults to the generator in essence dropping the CG power off line and now generator power goes to the AC panel. This switching occurs because a relay "sees" power from a specific source and switches to provide that power source to the coach panel.

It is my understanding that if the inverter switches are "on" and in the case of Liberty coaches where the inverter battery charging circuit has its own dedicated AC circuit shore power flows to the refrigerator (for example) through a relay that closes essentially taking power away from the inverter. Because the battery charging portion of the inverter is separately powered it continues to function.

[VegasDogMan]

Greg:
When I said AC Breakers OFF I was referring to AC Distribution Panel Circuits not incoming AC.

Let me restate again. I have AC coming to Distribution panel from CG as I can turn on Air Cond, Water Heater, Battery Chargers and other "Non-Inverter Circuits". For simplicity these are all off.

Now, no Inverter Output AC Circuits are ON and Inverter panel shows no DC Load as expected.

Turn on Breaker for Fridge and DC Load goes to 30A approx which indicates to me that AC is not being passed through inverter. In this case it appears that AC is being produced by Inverter since we've got a DC Load being shown when Fridge is On.

I'm going to tear into inverters this week-end and see if Inverter Transfer Switches are being fed by AC from the outside world.

I'll let y'all know what I find out if I don't fry myself.

Lee

[garyde]

Being new to the electrical nightmare of owning a Liberty I have to ask a dumb question. Is there an electrical schematic that the converter electrical techs follow when wiring the coach. Somehow I think the converters owe us a complete explanation of the above questions you have previously expressed. A series of color coded schematics showing the on and off circuits during each position of switches would be helpfull. Gary D get on this will ya.

Liberty, I believe has designed the inverter system much like a UPS system in a office. If power fails you will automatically be switched to Battery power. That Battery power has a limited time value depending on what is on. For the most part, this is determined by the circuit breakers listed as being inverter controlled. However, there is 3-5 amps @ 120volt of parasitic loads as well. So, there is not a by-pass because that would leave the 120 volt circuits more vulnerable to outages.
All Liberty wiring is two wire with a hot and a nuetral. These are numbered at the start point(fuse or breaker) and at the end point(load). I don't know if I have schematics for this Coach but my previous Country Coach Lexa came with electrical and plumbing diagrams. I will look into it.

[gmcbuffalo]

Lee
My coach has a circuit breaker for each inverter on the main AC panel. So I only have one wire leading into the each inverter. The "invert and charge" functions are controlled by each inverters remote. Look at the different wiring examples in the Heart manual and determine which diagram matches what you see in your coach. Maybe the AC breaker for "battery charger" is really the main supply for the inverters and incorrectly labeled. So instead of having two AC circuits going into the inverter (pass thru and charge) you have one input lead and the inverter either directs some AC to pass thru and some to charge. look at your inverter and see if you have two romex inputs and one output to the inverter AC subpanel or are there only one romex input and one output. As you will see in the manual it can be wired both ways.

I keep my loadsharing at minimum level so most AC is passed thru and the charge at a mimimum.
GregM

[VegasDogMan]

Eureka!! I have the answer!

Looked at the wiring on Inverters (I have two). Each one has Two AC Inputs - One for Charger and one for Transfer Switch. On each inverter these are tied together and protected by the breaker on my power panel labeled "CHARGER".

If I turn off both CHARGER breakers I have no AC going into Transfer Switch and inverter reverts to INVERT mode thus drawing DC amps from batteries.

Both chargers supply same bank of batteries.

To make thing worse, I'm in a CG with 30A power so, I turned off one CHARGER to keep from blowing breaker. By doing so, there was no AC being supplied to one inverter so it was drawing power from batteries and other inverter was passing AC via Transfer but also charging batteries so I saw DC load on Both inverters. One as a drain and the other supplying charge current.

In conclusion.. with fully charged batteries and both "CHARGER" breakers ON my DC load is near Zero when running MicroWave, Coffee Pot, TV, Fridge and more.

I'm a happy camper now that I know how things work.

Ain't knowlege wonderful?

Lee

[garylstevens]

Lee, we couldn't have done it without you.

Glad you got her figured out.

Now that you got that problem solved, what happend to your signature file and avatar?

Gary S

[VegasDogMan]

Gary:

Moved to new computer and forum didn't recognize me. Had to create new Login and forgot about signature file. Never had Avatar - maybee will do something this week-end about it.

Regards,

Lee
(no signature file for now - wife says we can't afford it!)

[hhoppe]

Way to go Lee, I'm saving a copy of your results for future entanglements with the Liberty.

Harry

[jelmore]

I'm joining this thread very late. Hope someone is monitoring it. Or, this could move to a new thread.

We've been full time for a couple of months now and the electrical is still a puzzle. I've set up power sharing (took a month to even find out that (I think) it means power available to charge batteries) for 25 amps on one inverter and 5 amps on the other. When we have 50 amps shore power, all is well and we get by fine. This week we have 30 amps. So, for this 30 amp situation, if I turn off both inverters at the remote panel, it seems I get all 30 amps (sometimes more?) to use. The batteries don't seem to get used or charged, so their voltage seems to stay steady.

A curious thing that I do not understand is that when the inverters are on at the remote panel and I turn off the battery charger breakers, then there is no shore power coming through, though the circuits that the inverters can power still work.

Much is still not understood.

Any one interested in any more discussion on this?

Thanks. I sure enjoy all the help here.

Eureka!! I have the answer!

Looked at the wiring on Inverters (I have two). Each one has Two AC Inputs - One for Charger and one for Transfer Switch. On each inverter these are tied together and protected by the breaker on my power panel labeled "CHARGER".

If I turn off both CHARGER breakers I have no AC going into Transfer Switch and inverter reverts to INVERT mode thus drawing DC amps from batteries.

Both chargers supply same bank of batteries.

To make thing worse, I'm in a CG with 30A power so, I turned off one CHARGER to keep from blowing breaker. By doing so, there was no AC being supplied to one inverter so it was drawing power from batteries and other inverter was passing AC via Transfer but also charging batteries so I saw DC load on Both inverters. One as a drain and the other supplying charge current.

In conclusion.. with fully charged batteries and both "CHARGER" breakers ON my DC load is near Zero when running MicroWave, Coffee Pot, TV, Fridge and more.

I'm a happy camper now that I know how things work.

Ain't knowlege wonderful?

Lee