Inverter By-Pass

[Jon Wehrenberg]

Not exactly, but I think you are close. I'm still trying to understand more than just Liberty, but right now my best guess is the CC has you set up it that when shore power or generator power is available to your coach, it goes to the battery charger portion of the inverter, but by-passes the inverter to feed power directly to the circuits powered by the inverter when not connected to shore power and the generator is not running.

Right now I have no clue how many coaches already by-pass the inverter and how many do not. I do know this however. If you have a coach set up so that you can easily access the wires into and out of the inverters, and can join the two sets together easily if necessary, don't waste any more time on this issue. You do not need to waste time or money installing a bypass. But if your inverters are not easily accessed and you do not have a by-pass, stay tuned.

[Joe Cannarozzi]

Jon what you just described is exactly how our bus and Heart work. When the inverter is on w/o shore power and you introduce it the thing automatically stops inverting and starts charging, and visa-versa.

The switch happens so quickly that none of the a/c stuff that is running is even interrupted when it happens.

It sounds like you have a simpler solution to that switch but here is some pictures of the relay that Heart used for an automatic switch in ours.

My Bus 395.jpg

My Bus 393.jpg

My Bus 394.jpg

I have a few so your welcome to one if you like.

[bill&jody]

jon-
i'll start off with, "i'm not positive about how this works, but..."
i think if you install this bypass switch, you need to ensure that it disconnects the a/c output of the inverter when bypassing.
if you tie the 120vac (shore) to the output of the inverter (its obviously already tied to the input), and the inverter is only intermittent, when it "comes back on", it will be feeding itself. most if not all inverters really don't like to do this.

furthermore, if you disconnect the input to the inverter (and the output of the inverter is still tied to the shore power via your bypass sw), and the inverting function still works, the inverter will try to drive the appliances as well, almost surely at a frequency slightly unequal to the shore power, and the two phases will periodically be adding then differencing. tho you prob'ly won't add up to 220, you'll surely damage something. seems that way, anyway.


just a thought.

wmm

[Jon Wehrenberg]

Bill,

Once my by-pass switch is switched from the normal inverter position to the "failed inverter" by-pass position the inverter input power is disconnected from the inverter, and the inverter output circuit is disconnected from the inverter (back feeds will ruin the inverter) and connected directly to the inverter input, this going straight through from the source to the electric panel.

On inverters with separate battery charger inputs I am going to suggest leaving them connected so if that section of the inverter is still functioning I will not lose battery charging capability.

The switches should arrive this week and as I go through the process of installing the switches I will document it all and then rather than discussing theoretical solutions we can discuss specific matters.

Joe,

The issue I have with relays is if they fail, especially the relay that disconnects inverter output so there is no danger of back feeding, the "automatic" system has just ruined a perfectly good inverter all because a $15 relay failed. As I mentioned previously making a by-pass automatic is easy, but with that automation comes a degree of risk that comes with the failure of that by-pass. Joe, check your current requirements on those relays. I need to handle 30 amps and your relays will not handle that. Maybe you have lower current requirements.

My set up is strictly meant to be used as a temporary fool proof means of dealing with an on-road failure of an important component. Besides, if I wanted to go to automation I would have to run wires back to my inverters, and if I am going to that trouble I might just as well go to the trouble of relocating them so I can access their input and output wires and then I don't need the by-pass switches.

[merle&louise]

Jon,

This is how Newell handles the inverter by-pass situation. If the inverter fails you unplug the cord from the inverter outlet and plug it into the power outlet. Hope this helps.

[Jon Wehrenberg]

Good idea Tuga.

They recognize the need and have taken a different approach. I'm almost done with installing the first by-pass and I am documenting it along the way.

[merle&louise]

Jon,

The only down side to Newell's approach is that if the inverter fails I would have to use a separate battery charger (which I carry onboard) to charge the house batteries. I guess that is because there is a converter in the inverter????

[Jon Wehrenberg]

Yes, that is correct. Do you have one or two inverters?

I have the same type inverter as you, 24V, and it is wired so the battery charger (converter) has a separate input set of wires. I am going to leave them connected in my by-pass with the theory being that the relay that closes to automatically power the inverter circuits may fail, thus requiring me to by-pass the inverter section, but the charging circuits (converter) may still function.

With my second inverter I can still afford to lose the entire inverter including the charging section because the remaining inverter will still function as a charger.

[merle&louise]

I only have 1 inverter; it's a Freedom 2500. I can not run the basement AC units without running the generator. The dash AC is my only source of AC when the generator is not running. I wish that I had an auxillary generator that runs off of the series 60 like Bob/03's Millenium; that is one neat setup!

My inverter runs the refrigerator, TV, microwave, and a few electric outlets.

[Jon Wehrenberg]

That's a heavy demand for a single 2500 watt inverter. Worse, but recognized by Newell, when that inverter quits you lose your most important circuits. I am surprised they did not provide a back up battery charger. That is a serious failure mode you should address before it happens. Your alternative if the inverter fails, as you are set up now is to run the engine to keep the batteries charged.