Inverter settings

[bwalz]

What do I set my inverters to when I plug into 30 amp? Should it be 15 for each or 30 for each? They are Trace inverters.

[Kevin Erion]

I would set them at 14 per side just for a little safety.

[Jon Wehrenberg]

Here is a loaded question.

Some conversions or inverters have provisions to either sense the available shore power amperage, or to have that value inputted on a control panel. Then the inverters are self limiting so they do not draw more power for battery charging than is available.

Other conversions of inverters are not as capable or as sophisticated and the amount of load they will draw has to be set manually. I have mine set for 5 amps based on how we use our coach. Since we rarely dry camp or rely on auto-start our batteries are usually topped off, or if we sit overnight and do deplete the batteries we typically will be driving the following morning and the alternator will recharge the batteries.

But our inverter settings are not easily done because we have to remove the remote panel and change dip switch settings.

I think the answer to the question is based not as much on how much shore power is available, but how does the inverter and the converter's electrical system work, does it shed load, does it sense other loads or does power management have to be done manually.

30 amps is not much and if our coach is typical we use about 10 amps just because of key off loads ranging from clocks to alarm systems to all other power drains plus the refrigerator. Plus anything else we may want on such as TVs, or an AC or the hot water heater are added on top of that before we even consider the inverter current draw.

[phorner]

Just had an "interesting" experience. While using the microwave this evening, we popped what I believed to be the pedestal circuit breaker, as we had a lot of current draw on one circuit.

I reset the pedestal 50 amp breaker and returned to the bus to find that only "Line 1" was powered up. This did not have a good feeling....

So, I went out and shut off the "bus" main breaker in the first, driver side bay; cycled the pedestal breaker back off and on; turned the "bus" main breaker back on and still no power to "Line 2"..... only "Line 1".

Back outside to go through the same routine again and this time, all is well inside. Power to both "Line 1" and "Line 2".

Could the Line 2 inverter be going bad or is it possible that some sort of thermal protection kicked in for a short time? The inverters were getting a direct shot of hot afternoon sun.

And, just because it seemed like the right thing to do, I adjusted the dip switches on both inverters to allow 5 amp charging instead of 20 amp. Probably better for power management in any event.

Any comments or suggestions? Should I be figuring on trading some diesel fuel for new inverters?

[Jon Wehrenberg]

Paul,

I don't think you have an inverter problem. What may have happened is the combination of an overloaded shore power breaker combined with an overloaded inverter.

As our coaches are set up each inverter has 50 amps of input power going to two separate circuits on the inverter itself. One circuit is the power to the charging circuit and one is the power that is a pass through. In other words when shore power is available to the inverter the inverter uses that power to charge the batteries plus supply the 120V AC output to the circuits set up in your AC panel.

When shore power is not available your batteries via the inverter supply those circuits. Your microwave is one of those circuits. I don't know what other circuits are powered along with the microwave, but they are possibly front or rear outlets, the refrigerator or the TVs. Regardless of what they are it is possible whatever circuits had loads they exceeded the 2500 watt output of the inverter so when the shore power tripped, it was followed by the inverter which likely took a bit to reset itself.

I think. Try to remember what loads were on the inverter circuits and if they exceeded 2500 watts.

The sequence may be reversed, but regardless it sounds like you exceeded the limit and the built in circuit protection worked as intended.

[phorner]

Thanks, Jon. I appreciate the comments.

The inverter "loads" don't appear to be evenly split, according to the labeling on the main breaker panel. So, it would appear that I need to keep a better eye on this.

When the missus is without both her cup of tea as well as the air conditioning, well, things can get ugly.....

[Joe Cannarozzi]

Paul

I had a failure once where I initially noticed I lost power out of a kitchen circuit. I was plugged in on 50amp shore power and the inverter was on but a/c current was just going through the inverter, it was in battery charge mode.

First instinct was to check the breakers none were tripped. Upon further investigation I began to realize I had no power to quite a few other things and eventually came to the conclusion that everything that was wired through the inverters fuse panel was dead. Another check there found no breakers tripped

What I eventually found was even though I was on shore power and A/C current is going through the inverter to its fuse panel we still had to exercise conservation and keep the total combined amps below 25 (we have 1 2500 inverter) whenever using multiple appliances and or outlets that come out of the inverters fuse panel or we would trip a breaker that is on THE INVERTER ITSELF.

To avoid this problem I needed to shut off the inverter while on shore power when I needed power simultaneously that combined added up to more than 25amp, even though coming from multiple circuits coming out of that fuse box.

For example like the toaster and microwave and the outlet in the bathroom with Deb running the curling iron, all simultaneously (all of which are wired out of that inverter fuse box), if shore powered is coming in and we simply shut off that inverter beforehand, no problems.

If that were tried on shore power with the inverter switch on, again I'd be down in the belly pulling panels to acess that breaker on the inverter itself.

I incorrectly assumed that because we were on shore power that each circuit coming out of that inverter fuse panel was capable of the rated amp per circuit simultaneous. We still could only pull 25amp max. COMBINED (2500 watt inverter) while on shore or gen. but with that inverter switch on. Otherwise I was down in the belly of the beast accessing the inverter to reset the breaker that resided there.

Is there any one else with a breaker located directly on the inverter like ours or that has experienced this?

[phorner]

Thanks for the comments, Joe. We used to have the same problem that you described in a Safari coach several years ago.

For some reason known only to the manufacturer, they had all the "heavy" loads on one side of the inverter circuit, and we were constantly having to go outside to reset the breaker on the inverter. This included all the kitchen outlets, the refrigerator and microwave oven plus the TV. I think that there were 2 breakers, a 15 amp and a 35 amp. Thanksgiving dinner was always a particular challenge....

We have succeeded in tripping the 50 amp pedestal breaker a couple of times with the Liberty, but usually I've been able to identify an obvious mistake on our part.

[Jon Wehrenberg]

Paul, I do not know why our pair of inverters does not alternate which one is charging the batteries, or why they do not equalize the battery charging duties, but they do not. I figured this out when I did the inverter by-pass.

But i can tell you that if you shut one off, the other picks up the charging load and will retain it even if you turn the other back on. On my coach it is a toss up which one is the battery charger. But....we have two separate pairs of #10 three wire cables going from the inverter circuit breakers to the inverters. One is connected to the wires that will by pass the inverter back to the CB panel, and the other is dedicated to the charger circuit. The only time that becomes an issue is if you have one leg of the 50 amp circuit heavily loaded and that also becomes the leg powering the inverter charger. That is something we do not have control over.

[0533]

Paul, I do not know why our pair of inverters does not alternate which one is charging the batteries, or why they do not equalize the battery charging duties, but they do not. I figured this out when I did the inverter by-pass.

But i can tell you that if you shut one off, the other picks up the charging load and will retain it even if you turn the other back on. On my coach it is a toss up which one is the battery charger. But....we have two separate pairs of #10 three wire cables going from the inverter circuit breakers to the inverters. One is connected to the wires that will by pass the inverter back to the CB panel, and the other is dedicated to the charger circuit. The only time that becomes an issue is if you have one leg of the 50 amp circuit heavily loaded and that also becomes the leg powering the inverter charger. That is something we do not have control over.

I'm not at all certain about the Liberty, but I believe The Marathon's Inverters are setup to operate in following way. Inverter 1 goes along with the main breaker, and inverter 2 with the Aux breaker. The Aux system runs the galley stuff, micro etc and if the system gets overloaded the Aux will shut down first as the Main has the refrigerator on it. Does this notion square with other Marathon owners?

Marathon gave me this rule of thumb when setting the inverters for power less than 50 Amps. 30 Amps set the inverters at 14/14, 15 amps 7/7, giving a small window for overloads I guess.