Can I add another inverter for residential fridge?

[gjkids]

I have residential fridge installed. Works great we love it. But now would like to run it off a separate inverter for the fridge only since it is very close to the battery compartment.

Is this feasible and what is the safest way to do it. I have a Greyhawk 30x with a 1000w inverter but the location of outlets make it difficult to tap into. Was wondering if it was easier to get 300w inverter just for the fridge.

Any input is appreciated, I do not something is a bad idea.

Thank you.

[Shokyle1]

I tried running my outside fridge on a 300 watt inverter it was not enough for the initial surge. I would look into the initial starting requirement of your fridge before buying an inverter.

[bluztoo]

Just with a rudimentary electrical knowledge I would say you can put an inverter anywhere you want and I’m sure you can have more than one. The bigger question will be about how many amps you’ll be pulling so you know what size inverter and whether you have enough battery. Each inverter draws some current just to work so check what you’re adding too.

[Lake Huron]

It is possible to run it off a seperate battery system.
My Northpoint has a residential fridge in it. The trailer has 2 separate battery systems. One main battery that powers everything 12VDC on the trailer and then it has two 6VDC batteries connected in series to get the 12VDC. The reason for the two 6V's is more reserve, longer run time.
The inverter that came with the trailer is a Xantrex Freedom 1000W. I upgraded it to a Xantrex Freedom XC 1000w. The difference is the XC has a built in battery charger so when I connect to shore power the inverter automatically charges the batteries connected to it.
Either way, you will need the inverter connected to an AC input so when you're connected to shore power the fridge will run off that instead of the DC battery/batteries.
Here is a diagram of how my fridge came wired from the factory.

[foglght]

a 1,000 watt inverter @ 110V = 9.09 amps

It is unlikely enough to run the fridge. You'd probably need a 2,000watt inverter and a 20 amp breaker.

But first you should probably get a current reader to see what the spike and running loads are. My norcold (8 cubic foot) was running around 7-8 amps.

[Lake Huron]

I was wrong. My original inverter from the factory was a Xantrex Pro XM1000.
Here's my old one;

The M stood for Modified sine wave. It handled my 21cuft Fridgidare fridge just fine for the couple years I used it. Like I said, the main reason i upgraded the inverter was to get one with the auto battery charging and the Freedom XC is a True sine wave instead of a Modified sine wave which plays better with electronics, which my fridge has lost of considering it has a programmable touch screen display built in the door. And yes, that fridge came from the factory too.
The Freedom XC 1000 that's in there now has worked just fine for the last 3 years with no issues, including any kind of overload. It even displays the load on it in the remote display screen and hasn't even come close to being overloaded.

[JimD]

Originally Posted by foglght

a 1,000 watt inverter @ 110V = 9.09 amps

It is unlikely enough to run the fridge. You'd probably need a 2,000watt inverter and a 20 amp breaker.

But first you should probably get a current reader to see what the spike and running loads are. My norcold (8 cubic foot) was running around 7-8 amps.

Yes 1000 watts @ 110 = 9.09 amps. The bigger thing to consider is that 1000 watts @ 12 volts = 83.33 amps. You size the inverter for the output you require but you better make sure your input is capable of providing the high amperage needed to produce the output. Wattage out will be close to wattage in. No free energy here.

These are very crude calculations to get you in some sort of ballpark. If you calculate 1000 watts @ 120 volts it would equal 8.33 amps. Same goes for 1000 watts @ 12.6 volts which equates to 79.36 amps. Just another area in the ballpark. This doesn't take into account the losses when the voltage is stepped up.

Inverters are good as long as you have the battery capacity AND a way of keeping the battery charged. Extra batteries plus a few hundred watts of solar is a good starting place. In summary, it is imperative you install a voltmeter to monitor the battery level. An inverter will keep sucking battery power until it reaches its low cutoff value and then shut down. If you are running standard batteries you don't want them to go below 12.1 volts because you can damage the battery which may result in it not being able to supply its rated amp hours.

If it were me I would use the current inverter and put my money into solar or better batteries. It almost sounds like I am against inverters which is not the case. My first experience with one was when I was a teenager (yeah, electricity had been invented). I used one to power an electric blanket in the back of my van when going to a drive-in theater. For you young whipper snappers, a drive-in is a movie screen outdoors where you sit in your car to watch the movie. Very popular in the 60s-70s (the 1960s not 1860s).

These days in my old age I use an inverter to power my Direct TV setup. We like having the TV on basically as background noise. I have increased my solar capacity to 400 watts to mostly keep up with it.

[Stavman]

When I run my DirecTV, boondocking. I run my solar panels directly to my 300w Portable power station, I have two.
It will continuously charge as I use the power station.
At night I'll use one power station if needed, charge it the next day.
No inverter in my 25r but really never needed it

[gjkids]

I am only looking to power during travel, which should receive a charge from the alternator. I have a class Greyhawk.

Do you agree , the 1000w inverter should be able to handle it ? When I put on a kill a watt meter, it only spikes to another 130-150 watts when plugged into 110v outlet.

[Jagiven]

Originally Posted by gjkids

I am only looking to power during travel, which should receive a charge from the alternator. I have a class Greyhawk.

Do you agree , the 1000w inverter should be able to handle it ? When I put on a kill a watt meter, it only spikes to another 130-150 watts when plugged into 110v outlet.

What readings did you get on your Kil-A-Watt meter in steady state? Without knowing this information, I cannot tell you if a 1000W inverter is appropriately sized.

FYI, you can have 3 different wattage readings, based on what it is doing at the moment.

• Startup Surge - Inrush of starting up the compressor and any other items associated with startup (highest reading, but only lasts a short time)
• Steady state while Cooling - Frig is on, the compressor, fans, etc is running and cooling off the frig. (medium reading, all equipment is running)
• Standby state - Frig is on, but the compressor is in standby mode, waiting for the thermostat to tell the compressor to kick back on, and start cooling again (lowest readings).

I would be primarily concerned with Steady State while cooling, next I would look at the surge load, when it turning back on to cool.

Recommendation is to size the inverter for no more than 80% capacity (standard for most electrical items). The smaller the inverter the less surge capacity it can handle, so the inrush could force you to a larger inverter.

So if your steady state while cooling is under:

• 800 Watts, a 1000 W inverter would be good
• 320 Watts, a 400 W inverter might be ok, need to look at the surge capacity. You noted 130-150W, might be an issue.

What I would not do is buy an inverter that is way over capacity for the load, as it will waste a lot of power. As the battery may drain faster than the alternator can recharge.

[gjkids]

The steady state was typically less than 100 watts, around high 80s.

Startup around 130 watts .

Defrost 140 watts.

See picture

[Shokyle1]

Your start up wattage will be substantially more than 130w.

[Shokyle1]

Here are the specs right from the web site. Amps on the left watts on the right.

[gjkids]

It appears it would still be within the 1000w inverter capacity