inverter circuit breaker panel question

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inverter circuit breaker panel question

August 14, 2019, 04:19:58 pm

I am about to install a small inverter for the refrigerator and realize I have power at the inverter panel while connected to shore power. I thought we had a transfer switch that only put power to that panel when there was no other power source. Am I misunderstanding the purpose of that ATS?

Re: inverter circuit breaker panel question

Reply #1 – August 14, 2019, 04:33:54 pm

The inverter breakers take power straight THROUGH the inverter when plugged in. In the event you don't have shore power you can turn on the inverter and ONLY those inverted breakers will have power.

Re: inverter circuit breaker panel question

Reply #2 – August 14, 2019, 04:36:35 pm

Do you still have the original inverter? You have two transfer switches under the bed, one for shore and one for the inverter/generator.

Re: inverter circuit breaker panel question

Reply #3 – August 14, 2019, 04:39:23 pm

The original inverter didn't have pass through capabilities, hence the need for the second ATS, power at the inverter was only used to activate the internal charger/converter.

Re: inverter circuit breaker panel question

Reply #4 – August 14, 2019, 04:57:47 pm

The inverter is a Xantrex sw 3012 but the factory transfer switches are under the bed. I thought the inverter panel was cold until the inverter came on. The inverter is wired the way I bought the coach. If they were pass through from the factory that would explain the power at the panel.

Re: inverter circuit breaker panel question

Reply #5 – August 14, 2019, 05:08:10 pm

The SW3012 does have pass through capabilities unlike the original, either way the main transfer switch powers all your circuits when on shore power.

Regardless, you can add a small inverter for the fridge with a built in ATS, or just put the fridge on a dedicated circuit that always runs off the smaller inverter. Several members have added a dedicated inverter for the fridge, I just run mine off the main inverter.

Re: inverter circuit breaker panel question

Reply #6 – August 14, 2019, 05:23:26 pm

Not my fridge, but all my electronics are are a small inverter wired directly to battery. I figure when running down the road, alternator and solar will keep batteries charged, when parked and on SP/GEN, inverter/charger, and solar will keep batteries topped off. Don't have to worry about ats problems.
If a problem with small inverter can just move electronics plug to big inverter and use it.

Re: inverter circuit breaker panel question

Reply #7 – August 14, 2019, 05:30:55 pm

I agree Jim, I eliminated (bypassed) my secondary inverter ATS when I upgraded the factory inverter as well.

Re: inverter circuit breaker panel question

Reply #8 – August 14, 2019, 05:38:23 pm

Quote from: jcus – August 14, 2019, 05:23:26 pm

Not my fridge, but all my electronics are are a small inverter wired directly to battery. I figure when running down the road, alternator and solar will keep batteries charged, when parked and on SP/GEN, inverter/charger, and solar will keep batteries topped off. Don't have to worry about ats problems.
If a problem with small inverter can just move electronics plug to big inverter and use it.

That is the plan other than adding a DPDT switch suggested by Roger so just flip a switch with a problem with the small inverter, which isn't so small after all. The Victron Phoenix 1200 came yesterday much larger than I expected, but does fit under the bed.

Re: inverter circuit breaker panel question

Reply #9 – August 14, 2019, 05:54:24 pm

Quote from: craneman – August 14, 2019, 05:38:23 pm

That is the plan other than adding a DPDT switch suggested by Roger so just flip a switch with a problem with the small inverter, which isn't so small after all. The Victron Phoenix 1200 came yesterday much larger than I expected, but does fit under the bed.

Switch is good idea, mine is manual. Cut line from inverter subpanel to coach fwd [electronics] receptacles, and put plug on it, and plugged into small inverter. On fwd receptacles breaker on subpanel, put receptacle on it, so will have move plug from one to the other in case of problem. I have an east west bed so have a bit more room.

Re: inverter circuit breaker panel question

Reply #10 – August 14, 2019, 06:06:59 pm

Cman,

We also use the DPDT manual switch for our small inverters that drive each independent appliance. This lets us switch from shore/generator to inverter, simple and dependable the KISS theory.

Mike

Re: inverter circuit breaker panel question

Reply #11 – August 14, 2019, 06:19:18 pm

I did mine with the plugs, because I did the same mod with the fwd ac on the main panel. Normally leave ac plugged in main panel, but when I want to run it off inverter, just plug it into inverter sub panel receptacle.

Re: inverter circuit breaker panel question

Reply #12 – August 14, 2019, 06:22:24 pm

I know of no one other than here running smaller inverters to invert local loads. The bigger inverters have a max efficiency that is higher and over more watts output.

If you are trying for max efficiency a smaller transformer Victron at some output level shows more efficiency than the bigger transformer American made brands,

Each foot of 12 volt wire consumes power.

That's why Foretravel located the batteries next to the inverter with large cables then distributed the 110 volt power.

So does every other rv made as far as I know.

Re: inverter circuit breaker panel question

Reply #13 – August 14, 2019, 06:31:00 pm

Quote from: Caflashbob – August 14, 2019, 06:22:24 pm

I know of no one other than here running smaller inverters to invert local loads. The bigger inverters have a max efficiency that is higher and over more watts output.

If you are trying for max efficiency a smaller transformer Victron at some output level shows more efficiency than the bigger transformer American made brands,

Each foot of 12 volt wire consumes power.

That's why Foretravel located the batteries next to the inverter with large cables then distributed the 110 volt power.

So does every other rv made as far as I know.

The smaller inverters are to get rid of the high idle amp issue. My Xantrex SW 3012 will eat up 24 ahrs during 8 hours of sleep just at idle. Can't turn it off or it will screw up the timing on the residential ref. The efficiency level doesn't come into idle conditions.

Re: inverter circuit breaker panel question

Reply #14 – August 14, 2019, 06:35:14 pm

Quote from: Caflashbob – August 14, 2019, 06:22:24 pm

I know of no one other than here running smaller inverters to invert local loads. The bigger inverters have a max efficiency that is higher and over more watts output.

If you are trying for max efficiency a smaller transformer Victron at some output level shows more efficiency than the bigger transformer American made brands,

Each foot of 12 volt wire consumes power.

That's why Foretravel located the batteries next to the inverter with large cables then distributed the 110 volt power.

So does every other rv made as far as I know.

I guess most Foretravel owners are smarter than owners of SOB! The distance between my small inverter to the 3/0 coach battery cable on the boost solenoid is about 18 inches. Really do not think much voltage drop or resistance when running 200 watt load through 3/0 cable.

Re: inverter circuit breaker panel question

Reply #15 – August 14, 2019, 06:41:20 pm

Bob,

Do what makes you happy and we will do what makes us happy.

Mike

Re: inverter circuit breaker panel question

Reply #16 – August 14, 2019, 06:43:26 pm

Craneman go to Beamalarm.com then to rv technical help then to adding an additional inverter. I got power for mine from the isolator, and put the inverter under the bed with the rest of the electrical. Been working for 3 years now wit a cheap 1000watt inverter.

Re: inverter circuit breaker panel question

Reply #17 – August 14, 2019, 06:52:43 pm

Quote from: bbeane – August 14, 2019, 06:43:26 pm

Craneman go to Beamalarm.com then to rv technical help then to adding an additional inverter. I got power for mine from the isolator, and put the inverter under the bed with the rest of the electrical. Been working for 3 years now wit a cheap 1000watt inverter.

That is where it is going and hooked up to the house side of the boost solenoid at this time. I had to get an inverter that could power a 22.6 cu. ft. refrigerator so the cheap one I had previously bought will get repurposed some how.

Re: inverter circuit breaker panel question

Reply #18 – August 14, 2019, 09:47:44 pm

Mine is an older unit and it does shut down. Once morning comes the 1450 watts on the roof make efficiency moot. I can run the microwave while still putting 500 watts into the battery. My only issue is getting through the night and having 12.2 volts or more in the morning. Just to add the Victron Phoenix 1200 is 92% efficient.

Re: inverter circuit breaker panel question

Reply #19 – August 14, 2019, 11:27:24 pm

At what power output? Where exactly is it 92%?

Re: inverter circuit breaker panel question

Reply #20 – August 15, 2019, 12:04:54 am

Quote from: Caflashbob – August 14, 2019, 11:27:24 pm

At what power output? Where exactly is it 92%?

Does it really matter where the peak efficiency is? Its output will surge on refrigerator start-up at 1200 watts and run it between 133 and 193 watts. Then with satellite and television on, it will rise again to whatever their draw is. Throw in computer charger, Netgear charger, phone chargers all on the same circuit. This is only for when solar is not available. There is no perfect target for the 92%

Re: inverter circuit breaker panel question

Reply #21 – August 15, 2019, 12:15:45 am

Chuck, your inverter sub panel is powered by the main panel (landline or generator) through the ATS switch at the foot of the bed. If there is no land line or generator power then the ATS switches the inverter sub panel to the inverter supplied power.

Unless your original wiring has been modified the inverter is not supplying power to the inverter sub panel when there is land line or generator power.

Use the maximum 12v cable that you can connect to your smaller inverter. The maximum length should not exceed that which will exceed a 1% voltage loss. This is based on amps at 12.5 volts to produce the maximum small small inverter output plus a bit for efficiency losses. The plus cable should include a fuse rated for about 50% more than the maximum current and a switch.

This is a good tool for calculating wire size, loads, lengths and voltage loss.
Bos'ns' Corner - Wire Size Calculator

Re: inverter circuit breaker panel question

Reply #22 – August 15, 2019, 12:24:08 am

Roger that was the question at the beginning of this thread. I had the main power breaker on and connected to shore power. When I turned off the inverter circuit breakers the power was cut off to each circuit. Does that mean it has been modified? The 12 volt power supply wire to the inverter will not exceed 3 ft.

Re: inverter circuit breaker panel question

Reply #23 – August 15, 2019, 12:34:09 am

Quote from: craneman – August 15, 2019, 12:24:08 am

Roger that was the question at the beginning of this thread. I had the main power breaker on and connected to shore power. When I turned off the inverter circuit breakers the power was cut off to each circuit. Does that mean it has been modified? The 12 volt power supply wire to the inverter will not exceed 3 ft.

Think the inverter/[SP/Generator] ATS should have supplied power to the inverter subpanel.
If you shut off breaker in your subpanel, of course no power.

Re: inverter circuit breaker panel question

Reply #24 – August 15, 2019, 12:43:55 am

The circuit breaker to the inverter on the main panel?

As originally wired, If you have the land line on then it powers the ATS to switch it to use land line power from the main panel to the inverter sub panel.

If you shut off the individual circuit breakers on the sub panel then each of those circuits will be off. The sub panel will still be powered. If you shut off the main breaker on the sub panel then the sub panel is off.

If it has been modified then the sub panel is always powered by the inverter either as it passes through 120v from the land line or the generator or when they are not available from the inverter. Your OEM inverter circuit breaker on the main panel is probably only 20 amps, enough for the original inverter. That means the max you can pass through is 20 amps. If you want to increase this then all of your wiring to the inverter and back to the inverter panel needs to be bigger as well as bigger circuit breakers.

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