Inverter reset when AC is running

[NOBOCO]

Hi everyone,
Did an inverter/charger install on my 19.5 and everything works perfect except when I’m running my AC on shore power it will run for about 10 mins then cause the inverter to reset. Inverter will reset and go on for another 10 mins and the same thing will happen. It’s only 1000w but when we’re on battery power we turn off most things at the breaker so it won’t overload the inverter. I thought that when on shore power the inverter was just a pass through and would overload when the AC is running. Any ideas?

[NavyLCDR]

Do you think it might help if you posted the exact make and model of inverter? Also, it sounds like you wired its output to the main input of your power panel?

My guess is that you are exceeding the limits of the built in automatic transfer switch because you wired it to main input of your power panel.

[NOBOCO]

It’s a Magnum 1000w MMS, I did buy it off Craigslist so I’m not sure how old it is. I did wire it straight to the 30amp main input. Is there a better way to do it?

[Bob K4TAX]

Originally Posted by NOBOCO

Hi everyone,
Did an inverter/charger install on my 19.5 and everything works perfect except when I’m running my AC on shore power it will run for about 10 mins then cause the inverter to reset. Inverter will reset and go on for another 10 mins and the same thing will happen. It’s only 1000w but when we’re on battery power we turn off most things at the breaker so it won’t overload the inverter. I thought that when on shore power the inverter was just a pass through and would overload when the AC is running. Any ideas?

The AC is pulling some 1800 watts. Likely the inverter sees this as an overload condition and shuts down. It cools down and then resets.

I'd say one needs to review the wiring and installation of the system. FYI - the 1000-watt inverter won't start or run the AC.

Bob

[NOBOCO]

I get that the inverter won’t run the AC when I’m not on shore power and didn’t plan to use it that way. I just thought that when I’m on shore power the inverter would basically act as a pass through for the 30amp and run everything as if I didn’t have an inverter.

From what I gather from the LCDR is that maybe I need a transfer switch in between the pedestal, battery and inverter? Wire the inverter as generator power?

[NavyLCDR]

Originally Posted by NOBOCO

It’s a Magnum 1000w MMS, I did buy it off Craigslist so I’m not sure how old it is. I did wire it straight to the 30amp main input. Is there a better way to do it?

https://www.magnum-dimensions.com/pr...rter-charger-0



You have a 20 amp automatic transfer switch connected to a 30 amp shore power distribution panel. The inverter/charger needs to be on a branch circuit feeding a single string of outlets, not your entire 30 amp power panel.

[Aussieguy]

Longshot....

is there good airflow so that the inverter can keep cool?
make sure cooling fan is working and clean.

[NOBOCO]

Aussie - good thought but I did make sure to cut holes in the sides of the bed so that it gets good air. The first time it fired up to charge the battery it was working it’s ass off and got hot so I did that immediately.

LCDR - that makes perfect sense. That will also eliminate the need to manually turn off the breakers when on battery power. Looks like I have a little research and work to do today. Thanks!

[NOBOCO]

Follow up to the previous response. Trying to wrap my head around how to do things. Do I need to just split the shore power and run one to the inverter like I have already and the other straight to the 30amp power for the 120V? Would this take care of the issue? Or do I need to isolate the breakers that I want to work only on shore power and remove those from the current block that is fed by the inverter?

[5picker]

1st, for the 120v side of the inverter to be protected, (and the rest of the output circuit) it needs a circuit fed from an appropriate breaker in the power distribution box in your R/V, not just split off the 30a main feed.

2nd, think in terms of what you want the inverter to provide power to and supply that circuit with the inverter output. That way, when on shore power, the transfer switch will provide shore power to that circuit and when no shore power, the inverter will.

In many R/Vs, the breaker that would feed a residential refrigerator feeds the inverter 120v input. The inverter output then feeds back to the outlet the refrigerator is plugged into. The inverter is inline with the circuit and everything is aptly protected.

[NOBOCO]

5picker - That makes sense. I had a question about your first point, before I got my hands on it and started screwing things up, the shore power ran directly to the 30amp main breaker. Are you saying this should have an inline breaker as well? I did install a 30amp breaker inline from the shore power to the inverter.


Second - Can I eliminate all of this by getting a larger inverter with a 30amp transfer? Would this be the "right" way to do it? Or would it still be recommended to use the inverter to only feed the circuits I want off-grid and not just the 30amp main?

[5picker]

Feeding the entire R/V with an inverter isn't the conventional way of installation. Sure you can do it, but without a properly sized inverter and a HUGE battery bank, it is an impractical method to follow.

Protecting your pass through circuits with a 30a feed breaker isn't a good plan either. Many circuits are rated for less and feeding them with 30a of power (if your inverter could sustain it as someone mentioned the transfer switch is rated at 20a) is asking for trouble.

You need to feed YOUR inverter for whatever it is rated for and BE SURE the output circuit wiring can handle that current load. Meaning, you can't output 20a of power into a 15a circuit and expect the wiring to be properly protected.

[NOBOCO]

First, thank you all for sharing your knowledge with. This is my second year camping in an RV and electrical isn’t my area of expertise. After looking at it a little more, my main drive to install the inverter was so that we would have power to the outlets while off grid and these run off the 30a main. We won’t run the AC off grid nor the microwave, fridge and water heater can run on propane which I expanded the system to be able to accommodate 2x30lb tanks which would last us weeks.

So long story short, safest and only correct way to be able to run the 30a main from the inverter will be to upgrade inverter to 30a pass through? I’ll post a drawing of the current system, circled items are changes.

https://imgur.com/a/7BL8PkG

[NavyLCDR]

Originally Posted by NOBOCO

After looking at it a little more, my main drive to install the inverter was so that we would have power to the outlets while off grid and these run off the 30a main.

The outlets do not run off the 30 amp main. The outlets run off a branch circuit breaker which is probably 15 amps. What you should have done is remove the outlet circuit wire from its 15 amp branch circuit breaker (and the corresponding neutral and ground wires) and ran that to the inverter output. Then run the AC input wire from the inverter back to the same locations that you removed the outlet circuit wires from.

The inverter needs to be inserted into a single branch circuit and should never be in the shore power inlet wiring. Unless you get a 4000 watt or larger inverter. But a 4000 watt inverter would be pulling about 350 amps from the battery at full load.

[5picker]

X2 everything NavyLCDR said plus installing a HUGE inverter and an appropriately sized battery bank is going to be crazy expensive just for the convenience of having ANY outlet powered when shore power is not available. And when only using one or a few outlets, the 12v power draw on that big inverter is going to be tremendous just having it on.

Pick a convenient circuit, wire your inverter to that circuit and enjoy camping.

[NOBOCO]

Understood. Would the outlet branch circuit breaker be located in a different location than the main box? Everything your saying tracks but the breaker for the outlets is not located on the main panel. I should be able to easily correct this with the wiring that currently exists. Again, thank you both for your patience dealing with newbie like myself.

[DES-1]

Originally Posted by 5picker

X2 everything NavyLCDR said plus installing a HUGE inverter and an appropriately sized battery bank is going to be crazy expensive just for the convenience of having ANY outlet powered when shore power is not available.

It doesn't have to be crazy expensive. Check out the sales on the Renogy 3000w pure sine inverter. Quality standalone auto transfer switches are under $100. And, I disagree, it is very nice to have all the 110v working, including coffee pots and microwave. You can decide what to use based on your battery capacity. If you get the itch to run the A/C off batteries, you're prepped and it just a question of adding 400+ AH of batteries to support.

[NOBOCO]

Yeah, we definitely don’t need the AC, and we run fine without 110v power. We tent camped for 20 years so any thing more than a lantern we consider a plus. Honestly I think I want the system mostly for a long term SHTF type situation. Im becoming less and less confident in the stability of society by the day and would just like to be prepared. I use a CPAP at home but don’t usually take it camping but if we were to stay off grid for more than a week my wife might kill me due to my snoring so I’d like the ability to use it if I needed to. So far Ive bought everything on Craigslist and spent around $500 for the entire system. And the only problem I’m having at this point is that the inverter is resetting while running AC on shore power, and I think the LCDR hit that on the head by pointing out that the inverter I currently have has a 20a transfer switch. I found a Renogy 2000w with 30a transfer for $180 on Craigslist so I’m going to pick that up and see how it does. Also going to throw in some more 30a breakers.

[NavyLCDR]

To both DES-1 and NOBOCO:
What size wire do you have running from the battery(ies) to the inverter? A 2,000 watt inverter can draw upwards of 185 amps. A 3,000 watt inverter can draw upwards of 275 amps. You are looking at 2/0 (00) awg wire guage. In addition, you are not going to pull 185 amps from a lead-acid battery for very long without killing it.

[Larry-NC]

Originally Posted by NOBOCO

Understood. Would the outlet branch circuit breaker be located in a different location than the main box? Everything your saying tracks but the breaker for the outlets is not located on the main panel. I should be able to easily correct this with the wiring that currently exists. Again, thank you both for your patience dealing with newbie like myself.

The outlets in a travel trailer are all on either one or two branch circuits. On the bigger trailers, most of the outlets are on a 15 amp branch circuit labelled General (or GEN'L), except for lavatory, kitchen sink, and outdoor, which are on a 15 amp branch circuit labelled GFCI.

In a smaller trailer, they are probably all on one branch circuit. Easy for you to test. Then all you have to do is:

1. Remove the hot (black) input wire of your inverter from the 30 amp breaker.
2. Remove the hot (black) wire from the breaker and connect it to the output terminal of the inverter.
3. Connect the input hot (black) wire of the inverter to the just-vacated breaker terminal.
4. Leave the neutral (white) and ground (green or bare) wires where they are.