No AC Power, Dead Inverter? Need Diagnosis Help & Recommendations

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SunFun

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Oct 24, 2021
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Texas
Hi All,

I just bought an RV, and I think the Inverter might be out:

Diagnosis Steps Taken:
  • DC 12V Power Works fine (lights, water pump, etc).
  • AC Power worked, when hooked up to house power, including Air Conditioning, Microwave, Plugs, etc. This is how I bought the RV about 1-week ago.
    • I now suspect the seller knew the AC power didn't work, when not hooked up to external power, and obscured that by not showing anything AC working while not hooked up. He ignored my text asking if I was flipping the correct switch... You live, you learn I guess. I still think I got a good deal, even if the inverter is dead.
  • It seems like everything on the fuse-box should theoretically be working fine, if everything powers up when hooked up to external AC power.
  • Flipping the red switch next to the battery-power switch appears to do nothing (with battery power on), and that switch doesn't light up.
  • I flipped all of the breaker switches under the bed.
  • 12.1v of power is going to the wires, in the inverter (tested with electric meter).
  • Unknown if any AC power is going out of the inverter; I can't access the back without removing the inverter.
  • I replaced both 25amp fuses on the inverter to be safe. Neither fuse appeared to be blown, which I guess is what it's supposed to do if +/- is hooked up backwards.
  • Unknown if any AC power is going out of the inverter. I might be able to check late tomorrow, when the contactless AC Power Detector (this: Southwire Tools 40116N NCV Detector 100-600V AC - - Amazon.com) arrives tomorrow.
  • I plugged into 3-prong outlet in back of the breaker-box, and no power there.
  • Photos of Inverter, Fuse Box, etc below.
Questions:
  • Is there anything else I should check? Other than using the voltage detector?
  • Is there an AC fuse somewhere? Could the 30A breaker be blown?
  • Am I possibly doing something stupid like flipping the wrong switch to turn on AC power?
Inverter Recommendation: (I might need a more powerful one anyway).

  • I may eventually add solar. RV has a 5k watt generator.
  • Almost certainly will add about $2000 to $3000 in lithium batteries soon. I have the budget, just haven't done the complete research yet.
  • I know some people switch to 24 or 36v. Is that worth it? Does that require a different inverter? (This isn't high priority, I'm just thinking ahead).
  • I might wish to sometimes run at once: refrigerator, 1x A.C. unit (in Texas), Power-hungry Desktop Computer, Dual Monitors, Wireless booster, Water Pump, and small electronics at once. It's probably better if I can mostly run off extrenal power, but lets say this is possible. Am I likely to need an inverter with certain specs?
  • The RV is a 2006 Forest River Sunseeker, 30-amp input, Currently has an Inteli Power Model PD9140A.

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donn

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Are you positive you have an INverter and not a CONverter?
Typically IF you have an inverter it will lock out high amp devices like the AC. A typical battery bank would not support those things more than a couple of minutes.
As a rule of thumb those items that work when connected to AC will only work on shore power.

Your PD9100 is a stamdard CON verter. There is nothing wrong with your system. You just do not yet understand you have 2 electrical systems in your trailer.
 

DonTom

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I know some people switch to 24 or 36v. Is that worth it? Does that require a different inverter? (This isn't high priority, I'm just thinking ahead).
IMO, keep it at 12V. Yes, both the inverter and converter will need to be changed and much more.

The way my new RV works:

The genny or shore power goes to every AC outlet inside or outside the RV.

But if using the inverter, none of the outlets in or near the kitchen will work. All the others will. This is because most kitchen items draw more than the inverter can handle. Stuff such as coffee makers and MW ovens draw more than the stock inverter is cable of (1,200 watts). The MW oven needs 1,550 watts.

BTW, a CONverter charges your house battery. Maybe also your engine battery (some do and some don't).

An INverter makes 120 VAC from your house battery. But usually at much less capacity than your genny.

Your top photo is a CONverter, not an inverter.

-Don- Reno, NV
 
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Henry J Fate

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The PD9140A is a converter charger and will not provide 120 volts of AC power from the batteries. You will need to install an inverter charger.

Selecting an inverter charger size will depend on how much power you desire. You can size it to power all your appliances except for the air conditioning system which will only run if you are plugged in or running the generator.

To size the inverter, figure out what appliances you would like to operate with the inverter then check the power requirements of those appliances. Look at the power consumption of the appliance that uses the most power (probably the microwave) and add another 25%. That will get you at the minimum size.
 
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SunFun

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Texas
Are you positive you have an INverter and not a CONverter?

Ohhh! (Face-palm) Seems all of you are right!

Seems I need an inverter then, or just figure I won't be running much when off-the-grid. I suppose next on my list is a wattage meter, so I can figure out how much I'm actually using. It's also possible I'll just be unable to run most of my stuff when "off the grid."

I didn't test EVERY plug, but maybe I'll do that tomorrow, to see if any of them work. Also see if there is any inverter at all in the unit.

edit: Seems inverter-generators might be another option. They don't appear to cost significantly more than an inverter itself (based on about 5 minutes of research, I might need to shop around).


vs $250 for 2kw inverter.
 
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Henry J Fate

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Ohhh! (Face-palm) Seems all of you are right!

Seems I need an inverter then, or just figure I won't be running much when off-the-grid. I suppose next on my list is a wattage meter, so I can figure out how much I'm actually using. It's also possible I'll just be unable to run most of my stuff when "off the grid."

I didn't test EVERY plug, but maybe I'll do that tomorrow, to see if any of them work. Also see if there is any inverter at all in the unit.

edit: Seems inverter-generators might be another option. They don't appear to cost significantly more than an inverter itself.


vs $300 for 2kw inverter.

You will need a transfer switch to go with the inverter or buy an inverter with a transfer switch built in (a little more expensive than your $300 estimate).

You will also need someone technically able to wire and install the inverter which must be done safely and correctly.

A less expensive way of inverter power is to buy the 2000 watt inverter only (not an inverter charger) for $300 and mount it in the living area which allows you to plug into the inverter directly. This method does require some precision wiring.

An inverter charger would provide 120 volts ac, charge the batteries and most have a built in transfer switch. This would replace the PD9140A.
 
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Pgh_AL

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Ohhh! (Face-palm) Seems all of you are right!

Seems I need an inverter then, or just figure I won't be running much when off-the-grid. I suppose next on my list is a wattage meter, so I can figure out how much I'm actually using. It's also possible I'll just be unable to run most of my stuff when "off the grid."

I didn't test EVERY plug, but maybe I'll do that tomorrow, to see if any of them work. Also see if there is any inverter at all in the unit.

edit: Seems inverter-generators might be another option. They don't appear to cost significantly more than an inverter itself (based on about 5 minutes of research, I might need to shop around).


vs $250 for 2kw inverter.
That's exactly how my RV is nothing AC works off grid only when generator is on or plugged in to shore power. I have the exact set up as you have .

So your seller didn't fleece you after all 😆
 

Edd505

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Elephant Butte, NM

Ohhh! (Face-palm) Seems all of you are right!

Seems I need an inverter then, or just figure I won't be running much when off-the-grid. I suppose next on my list is a wattage meter, so I can figure out how much I'm actually using. It's also possible I'll just be unable to run most of my stuff when "off the grid."

I didn't test EVERY plug, but maybe I'll do that tomorrow, to see if any of them work. Also see if there is any inverter at all in the unit.

edit: Seems inverter-generators might be another option. They don't appear to cost significantly more than an inverter itself (based on about 5 minutes of research, I might need to shop around).


vs $250 for 2kw inverter.
Your link is not an inverter generator, it's an open frame work gen. Inverter Generator << That link you will see inverter generators, if it does not say inverter it's a loud work unit. You will need at least a 3500 watt to run a single A/C. You might also check Harbor Freight for a Predator inverter Generator, they are getting good reviews. From you posts it's clear you are new to the RV world. Asking questions is good and there are many RV forums to just read through, your not the first with most questions. Google is your friend.
 

SunFun

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Texas
That's exactly how my RV is nothing AC works off grid only when generator is on or plugged in to shore power. I have the exact set up as you have .

So your seller didn't fleece you after all
Yeah, seems my ignorance got the better of me. ;)

I'll have to double-check whether AC (and Air Conditioning) works when the generator is running. It would seem silly to have a 5kw generator that only charged the batteries, but who knows.

A less expensive way of inverter power is to buy the 2000 watt inverter only (not an inverter charger) for $300 and mount it in the living area which allows you to plug into the inverter directly. This method does require some precision wiring.
I think that would work & probably the right call. Based on replies, I assume the inverter works, I was just ignorant.

What I'm thinking is have the inverter next to a wall-plug. Then run a power-cord that I can easily swap between either the inverter or wall power, depending on whether I want to power off of the batteries or camp-power.

There might even be a dual-plug-power-input-switch thing which does that, but I can't seem to figure out the right search-term. The idea being it plugs into two outlets, and you can flip a switch to change input.
 

Mark_K5LXP

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Generally when away from shore power and you want to run AC devices you fire up a generator. Does your RV have a generator?

Mark B.
Albuquerque, NM
 

Rob&Deryl

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That's exactly how my RV is nothing AC works off grid only when generator is on or plugged in to shore power. I have the exact set up as you have .

So your seller didn't fleece you after all 😆
Most RVs are like yours. My 5th wheel has no inverter. Ok, no TV when boondocking (oh no tv stations or cable either, duh), have to do without toaster or microwave. Hmm, seems to me there was a time before those and people survived.
 

SunFun

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Texas
Your link is not an inverter generator, it's an open frame work gen. Inverter <<<< That link you will see inverer generators, if it does not say inverter it's a loud work unit. You will need at least a 3500 watt to run a single A/C. You might also check Harbor Freight for a Preditor inverter Generator, they are getting good reviews. From you posts it's clear you are new to the RV world. Asking questions is good and there are many RV forums to just read through, your not the first with most questions. Google is your freind.
There's a Harbor Freight down the street & I have one of those paid-accounts with them. I'll have to check there to see if they have a Predator Inverter Generator & their price.

Google is not your friend ... but I'm maybe drifing a little off topic, hah. Yes, I did search. However, you might have noticed I made a critical mistake in the OP that was causing me to get bad results. It only took a few seconds for many people here to spot the mistake, and save me a giant headache.

Generally when away from shore power and you want to run AC devices you fire up a generator. Does your RV have a generator?

Mark B.
Albuquerque, NM
It does have a generator, but I don't know if it is producing AC or not. I'll check tomorrow, when I'm back at the RV.

Most RVs are like yours. My 5th wheel has no inverter. Ok, no TV when boondocking (oh no tv stations or cable either, duh), have to do without toaster or microwave. Hmm, seems to me there was a time before those and people survived.
My plan is to full-time the RV and work. I'll survive, but can't work without my computer. So it would actually be worth (to me) a few grand to get setup properly.
 

DonTom

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I'll have to double-check whether AC (and Air Conditioning) works when the generator is running. It would seem silly to have a 5kw generator that only charged the batteries, but who knows.
It's an overkill for sure, but it will use a lot less gas with a small load than it will with a larger load, so it's just not that big of a deal. Genny's need to be exercised a bit, especially in the rainy winter time. The parts inside need to be dried out every few weeks or so. Best to use a heavier load, however. I use a 120 VAC heater and run the genny for about 30 minutes or so.

The most use my genny gets is such exercise. It is rarely used, except when I boondock for a few weeks straight at Organ Pipe Cactus Nat'l Monument,. Usually every year around December.

It's best to NOT use the genny when cold to heat a meal for a minute or so. That's one of the reasons I did this in message number 59 there.

-Don- Reno, NV
 

SunFun

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It's an overkill for sure, but it will use a lot less gas with a small load than it will with a larger load, so it's just not that big of a deal. Genny's need to be exercised a bit, especially in the rainy winter time. The parts inside need to be dried out every few weeks or so. Best to use a heavier load, however. I use a 120 VAC heater and run the genny for about 30 minutes or so.

The most use my genny gets is such exercise. It is rarely used, except when I boondock for a few weeks straight at Organ Pipe Cactus Nat'l Monument,. Usually every year around December.

It's best to NOT use the genny when cold to heat a meal for a minute or so. That's one of the reasons I did this in message number 59 there.

-Don- Reno, NV
That makes sense, that the generator would adapt to load.

The RV came with 2x Continental Batteries Part#: TM-27 CCA: 625 RC: 155 . https://www.continentalbattery.com/assets/Marine_ZFold2017.pdf Apparently, the "RC" is minutes at 25 amps, so if I understand correctly I have 25*155/60 = 64.5AH/each, or 130AH total, but these aren't deep-cycle. So, probably not a great idea to run much at all off the house-batteries.

I'm currently estimating I'll buy about 600AH to 800AH in lithium batteries.

It seems most of the inverters above 2kw are rather expensive and with few or fake reviews. So my idea is to perhaps run more than one inverter. One for my computer, monitors/tv, small accessories (1kw to 2kw). Another 2kw for the Air-Conditioning (need to check it's specs), or only 1x 1500w item at a time, perhaps hooking that up to house-power. That way I'm less likely to trip the inverter my computer is running off of.

Short-term, I'll be running off camp-power for the next 2-months, so I have some time to plan this out.
 

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Pgh_AL

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Yeah, seems my ignorance got the better of me. ;)

I'll have to double-check whether AC (and Air Conditioning) works when the generator is running. It would seem silly to have a 5kw generator that only charged the batteries, but who knows.


I think that would work & probably the right call. Based on replies, I assume the inverter works, I was just ignorant.

What I'm thinking is have the inverter next to a wall-plug. Then run a power-cord that I can easily swap between either the inverter or wall power, depending on whether I want to power off of the batteries or camp-power.

There might even be a dual-plug-power-input-switch thing which does that, but I can't seem to figure out the right search-term. The idea being it plugs into two outlets, and you can flip a switch to change input.

The Generator will run everything including the AC when running charge your house battery while doing so . That's the way mine is. Im totally satisfied with this set up . The only time it get a little difficult is when it's extremely hot out.

With out shore power for constant operation of the AC . But other than that it's fine . I just want to add another house battery for added amp hrs. I do a lot of off grid Boondocking and the TV and fridge are the only constant drain .

But i can run the best part of 24hrs before I need to charge with just the single house battery.
 

DonTom

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So, probably not a great idea to run much at all off the house-batteries.

I'm currently estimating I'll buy about 600AH to 800AH in lithium batteries.
And you will also need a high power lith converter. At least 80 amps. And perhaps thicker wires. 600 AHs of lith will cost you several thousand bucks, add about another thousand bucks to get to 800AH in lith.

That's a lot of AH in a lith battery. They are still around 13.0 volts when 95% discharged. They don't compare well to the same amount of AHs in a L-A battery because of the big voltage drop near the end of the L-A discharge.

But yeah, you do NOT want to see a "CCA" or even a "MCA" rating on a house battery. That's a major clue that it is not a true deep cycle battery even if it says "deep cycle" all over it. Same goes for the word "Marine". The Marine so-called "deep cycle" is only a little bit better than using an engine starting battery.

With batteries, an AH is not an AH unless the spec is at a certain current draw. That is what RC (reserve capacity) is. House batteries are designed for low current draws for a long period of time. Engine starting batteries are the opposite, very high current for a very short time, such as starting an engine.

"Marine batteries" are somewhat in-between the two as they are designed to start an engine as well as run some other stuff on the boat that draws much less current.

But that doesn't mean you cannot use one in place of the other, just won't work as well or last as long. Besides, I think the norm is to use the house battery to start the genny. At least my Y2k RV does. Not sure about my new RV yet.

But how much lith battery you need really depends on how you use your RV the most. If you need 800AH of lith, you must have a very large RV and want to run a lot of stuff for a long time boondocked.

-Don- Reno, NV
 

Mark_K5LXP

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Batteries don't create energy they just hold it. No matter what kind of Ah bucket you have - lead acid or lithium - that bucket needs to be refilled with something. So even if one were to deploy a battery and inverter system large enough to run A/C for some number of hours, at some point those Ah will need to be restored, plus conversion losses. So while one might gain some ability to run A/C off battery for a period of time, it's only a matter of time before a genset needs to be run no matter what.

Mark B.
Albuquerque, NM
 

JayArr

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You can't run Air Conditioning on an inverter. It's a heavy inductive load, it will deplete your batteries in less than an hour if it works at all and it is prone to blowing the power transistors right out of the inverter (I repair inverters). :)

If you want AC you need shore power or you need to run a generator.

If you can live without a microwave you can make do with a small inverter, (500W?) to run your computers and/or TV. If you want to run your microwave without starting your generator you will need about a 2000W inverter.

There is savings to be had with a large inverter because larger inverters have integrated transfer switches AND they can also include heavy duty three-level chargers. You want this! a 2000W inverter with a 75A charger will bulk charge your batteries to 80% in a couple of hours. This keeps your generator run time low. You get everything you need in one box and that simplifies wiring and reduces installation costs.
 

Gary RV_Wizard

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You stated the RV already has a 5KW generator. It produces 5000 watts of 120v power and all your 120vac stuff will run fine off it - doesn't need to be an "inverter generator" to do that. There are some advantages to an inverter-generator, but the output power is the same with a non-inverter type. One of the things the generator powers is that 9140 converter, so your batteries get recharged while the generator runs.

Your laptop probably has a 12v power module available so you could plug it to a 12v outlet for charging rather than 120v, but an small & inexpensive portable inverter will also handle it nicely. A simple model like the one below would do the job for laptop and phone charging. You would need to add a 12v outlet capable of delivering 30-35 amps to supply power to the inverter.

 
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Mark_K5LXP

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JayArr is correct but there is an efficiency penalty for running small loads with a large inverter. The large inverter is a must have for the microwave but is swatting flies with a hammer running lesser loads. Maybe not a huge consideration if replenishing with genset power but if boondocking with solar, you're peeing away a percentage of that fleeting power. No right or wrong way to do this, but there is a sweet spot that makes taking cost, value and capability into consideration.

Mark B.
Albuquerque, NM
 
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