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Inverter On or Off?

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I'm following an interesting discussion on another forum re the subject. Some say "on" never turn it off. Others say "off" never turn it on (except to use it). I don't see why you would leave it on and subject it to all that wear and tear for nothing. On the other hand, I can see leaving it on if traveling or if expecting to lose shore power.

What's the consensus here?

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The "leave the inverter on/turn it off" discussion really revolves around how you are using the coach. The main "turn it off" is that while dry camping and not using inverter-powered appliances you do NOT want to leave it on-- it uses valuable 12 VDC power to just be in stand-by mode.

Other times, the on/off decision becomes less relevant.

But, here is an answer based on our situation. We have a residential refrigerator (factory option) and MSW inverter. Rather than run the refrigerator on MSW (may be OK, or may not) we turn off the inverter when driving, BUT monitor refrigerator internal temperature and if necessary either turn on the inverter or start the generator. Here is what we use:http://www.acurite.com/indoor-outdoor-thermometer-00380.html

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If the inverter is an inverter only, then I would only turn it on while inverter power is needed. If it is like most of the newer ones that inverts and converts, then most likely there is not another converter on board the coach, you would need to leave it on when shore or generator power is present for the purpose of keeping the house batteries charged.

The newer technology PSW "pure sine wave inverters" are fine for powering almost any appliance, while the MSW "modified sine wave" inverters can power many appliances, but not all.

As Brett points out, his residential fridge may not be good on MSW, I use a Samsung French door residential fridge, mainly because when I installed, it was the only one that I could find that the manufacturer stated that I would be fine on MSW. I still use a MSW 3000 watt that runs the fridge and other appliances.

But have since installed a 5000 watt PSW that I power off my chassis batteries, they are 24 volt, with 24 volt alternator 210 amps, plenty enough to run the bus and the 24 volt inverter for the roof air while traveling.

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Ours is in the "off" position unless we need to use it. If traveling down the road and one of us wants a fresh cup of coffee, it is easier for us to start the generator for a few minutes. So we do that.

When boon docking at Wally World, we'll also run the generator. We try to park further away from the crowd but there are usually big rigs nearby that are running refers and other campers running their gen sets. At lights out.....we turn the generator off.

When really dry camping, out in the woods, we'll run the inverter in the evening, and set the generator to come on automatically at about 45% - 50% battery power.

Blake

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Many good points brought up here. I hadn't thought about shutting off some dual units and not charging your batteries because of it. My on/off switch on the RC7 GS panel if you tap it quickly will turn just the inverter side of the dual unit on or off, if you press and hold the same switch generator will start.

Driving down the road I run the inverter for the refrigerator its a MSW and my refrigerator can handle MSW. Depending on the time of year we often travel with the generator on for additional A/C throughout the interior, same if parked for the night with no shore power, plus the generator drowns out some of the exterior noise at truck stops.

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I called Magnum this morning and asked the tech this question. Bottom line is it makes no difference...leave it on or off until you need it. The only thing she emphasized was that it should not be left on when in storage. If the power should go off and the inverter start working, eventually it would run down the batteries. I leave mine off, until we need it.

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Our inverter is on 24/7. Our refrigerator is on the inverter and we are plugged in when home. We have stayed several times at WalMarts with no problems. We do have auto start but I am not sure if it works because the batteries have never gotten low enough to need it.

Herman

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If our inverter is off it is because something is broken! We use 120V AC current all the time and keep it handy. It runs our residential refrigerator while we are on the road. We frequently have our electronics (computers, cell phones, tablets, two way radios, etc.) plugged in, charging, while traveling. When we stop driving for lunch or a rest stop, we can flip on the TV and check the weather or news. It is just like living at home, the AC electric is always there.

We have automatic generator start function on the inverter and it turns on the generator when the battery charge drops too low. With this function, I never have to worry about damaging the batteries by letting them discharge below the recommended limit. In fact, Louise frequently uses the auto gen start in the morning when we are boondocking. She turns on the coffee pot. The draw on the batteries will trigger the auto gen start and we up and running for the day. The generator will run until the batteries have reached full charge and then the auto gen start function automatically shuts down the generator and we're back drawing on the batteries through the inverter.

When the coach is in winter shut-down, parked next to our house, it is plugged in to 50A. The inverter is on then because it keeps the batteries charged. The auto gen start function is still active and I didn't realize there is an additional benefit until recently. If the generator is inactive for a month, it will automatically run the generator for it's monthly exercise. That isn't the best situation as the generator is running in a low load condition but it does take care of the generator if I've missed the monthly exercise schedule.

So I view the inverter as the heart of the electrical system in our motor home. I also realize that not all inverters are created equal. Without many of these functions and how they are integrated into the electrical system the value of keeping the inverter on may be much less.

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Ours is off when parked at our home as we have shore power, but the charger is left on. When we hit the road, the inverter stays on till we get home again.

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I leave mine on continuously unless I take it into the shop or otherwise leave it not plugged in while not in use.

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I am with the "on all the time guys" unless I am really needing to conserve power due to limited generator time limitations and then off only rarely. Even boon docking the inverter is on even when we are not as it avoids loss of power to electrics that don't have battery back ups on clocks and timers. Likewise when parked at home, i am on 50 amp service and so far no issues.

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Just going to add a little item to the thread regarding the Inverter / Charger.

On the way North from the Southern part of the country, where we went to find some warmer weather for a time. The charger portion of our Inverter / charger failed.

Took me some time to figure out that the charger had indeed failed. The only indication in hindsight was the presents of noise in the video display for the rear view camera.

When driving, generator off, there where dark and light streaks present. After removing the positive feed between the charger and the battery bank's, I restarted the Coach engine and no more noise on the screen. INTERESTING !!!

It's been an ongoing issue that would come and go. But the charger diodes are shorted and I need to check for other items that could have failed yet.

The second item that told me something was wrong, was the fact that the coach batteries would read 13.5 volts after shutting down the engine and starting the generator the voltage would drop to 6.25 volts.

Remember! the battery charge was 13 plus volts and as soon as the generator was started - the battery level dropped to 6.25 volts. RED charge LED and a hot smell coming from the Xantrex unit. Not Good !

Now to replace or rebuild question as this issue falls into one of my skill sets. LOL

Rich.

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Our inverter is also a converter, so we leave it on all the time. When connected to shore power it is charging the house batteries.

I am not sure if the generator when on charges the house batteries and if the converter charges the chassis battery. Anyone know for sure?

Tim

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It all depends on your needs. If you have no equipment needing AC power all the time, even when/if the grid goes out, then leave the inverter section turned off and let the battery charger do it's work. Most inverters are also "converters" and supply the extra current needed to run your DC power system(lights, pumps, etc) so leaving the charger section on also leaves the converter section operating.

But if you have some electrical devices which you don't want to turn off when/if shore power goes out then turn the inverter section on so it's ready to pick up when shore power is out or disconnected. You will have to either make sure your generator is wired to kick in when the batteries get too low if the grid is out for too long. Or be aware of how long your batteries can go with the grid off and the particular AC load connected so you don't run the batteries down.

The large inverter/chargers(Freedom 458-what I have) are designed to work in tandem with the shore power and some even have ways to use limited shore power to augment(share) the AC load. But it's really up to your needs as to if you want the inverter ON or OFF when stowed. The electronics won't wear out because it's left on.

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Our inverter is also a converter, so we leave it on all the time. When connected to shore power it is charging the house batteries.

I am not sure if the generator when on charges the house batteries and if the converter charges the chassis battery. Anyone know for sure?

Tim

Tim,

Welcome to the FMCA Forum.

The device (sounds like you have an inverter/charger) works exactly the same on generator as it does on shore power. All it knows it that it has an "external source of 120 VAC".

Yes, all coaches (at least all I have ever seen) do charge the house battery bank from shore power or generator.

Chassis battery charging is a LOT more "some do, many do not". Easy to tell with a digital voltmeter.

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Thanks Brett,

I am trying the Forum out for the first time and already helpful. I am not sure I will every understand it all...but trying. So if I test the voltage of the line into the battery I should be reading 13+volts like I do with the line leading into the house batteries?

Inverter/converter question, what are the most common reasons for the inverter/converter to trip a breaker? My has been tripping over the last 3 or 4 days about 3-4 times daily. A reset works, but again only lasts 5 or 6 hours. I have a good EMS system and nothing is tripping there from low voltage, high voltage, etc.. I am connected to 50 amp shore and have been at this spot for about a month. Would a faultyish transfer switch cause it? It is working, but it has thumped a couple of times when I turn on the heat pump. I thought I would open the box and at least check that everything is torqued down as it should be.

Tim

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Tim,

My reply in SOLID LETTER CAPS.

Thanks Brett,

I am trying the Forum out for the first time and already helpful. I am not sure I will every understand it all...but trying. So if I test the voltage of the line into the battery I should be reading 13+volts like I do with the line leading into the house batteries? YES, IF YOUR CHASSIS BATTERIES ARE BEING CHARGED, THEIR VOLTAGE WILL READ IN THE SAME RANGE AS YOUR HOUSE BANK WHEN IT IS BEING CHARGED-- 13.2-13.5 VDC IN MOST CASES.

Inverter/converter question, what are the most common reasons for the inverter/converter to trip a breaker? WHAT BREAKER IS BEING TRIPPED, AND WHAT INVERTER/CHARGER DO YOU HAVE?

Would a faultyish transfer switch cause it? It is working, but it has thumped a couple of times when I turn on the heat pump. I thought I would open the box and at least check that everything is torqued down as it should be. YES, CHECKING THAT ALL CONNECTIONS IN THE ATS, AS WELL AS WHERE SHORE POWER COMES INTO COACH AND ALSO AT THE MAIN 120 VAC BREAKER PANEL ONCE A YEAR IS A VERY GOOD IDEA. OBVIOUSLY WITH SHORE POWER, GENERATOR AND INVERTER/CHARGER OFF!

Tim

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...The inverter is on then because it keeps the batteries charged...

The inverter does not charge the batteries...the charger does. Therefore, unless you have one switch that controls both functions, you do not need the inverter on. I have two sets of switches...charger on/off and inverter on/off. The charger is on all the time, the inverter is turned on when we need to to "invert" something. :D

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The inverter does not charge the batteries...the charger does. Therefore, unless you have one switch that controls both functions, you do not need the inverter on. I have two sets of switches...charger on/off and inverter on/off. The charger is on all the time, the inverter is turned on when we need to to "invert" something. :D

Five, same way I operate ours. I will turn the inverter on 10 minutes prior to unplugging the shore power, when we arrive at our destination after I connect to the CG power I turn it off, again if I remember. Usually its the next morning when I check the state of the battery charge I realize I left the inverter on standby.

Ours operates the same, the on/off switch only controls the inverter, not the charger portion of the unit. After we purchased the unit I couldn't figure out how to turn the inverter on (button not labeled) I would press it until the light would blink and the generator would start, we ran 3 months with no inverter until I called Xantrex. Quick push of the button controls the inverter, press for longer than 3 seconds the generator will start/stop. DW reminds me of that day often :blink:

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The absolute truth is there is no standard as to where anything is located or routed.

I was tasked this last fall to go get a friends coach ready for the road. There had been a medical emergency and I was asked to get it secured so FMCA Assist could pick it up. The outside was pretty easy but I had never been in this coach and finding all the switches was a challenge.

Bill

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