smallest inverter that can start dorm-fridge

Have a travel trailer with an "outside kitchen" that features a 120V, 60Watt bar fridge. I am wondering what the smallest size inverter would be to run this, when figuring the initial startup load? I may end up just replacing with a cooler for as much as it is needed (have LP fridge inside).

Anyone have experience with these small fridges?

I just posted this in another thread, copying here as it should work:

I ordered two of these last week for $15 each. They seem to put out their rated wattage unlike most cheap inverters. I was able to run two 120v power drills at once (~150w each with about 350w each surge). I tried to overload it by starting both drills at the same time plus a 100w worklight but it kept going fine, didn't even blink the light. For the money, I like them. Will keep them in the cars for who knows what.

The tricky part about fridges is that some don't like modified sine waves. The inverter above is a modified sine wave (like most cheap inverters) but it must be a bit cleaner wave than my other cheap inverters as it runs my fans without weird noises just fine, where my other non-pure sine inverters wont.

Usually dorm style fridges don't care.

The other big challenge with compressor driven fridges is the startup current, which is what I am trying to confirm I can get to work.

rayfound said:

The other big challenge with compressor driven fridges is the startup current, which is what I am trying to confirm I can get to work.

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That could be 120, 150 or 200w, who knows. You won't have a problem with that 400w w/800 surge unit, but I've read the reviews on many 150w inverters where people complained it wouldn't start their small fridges.

I'll try it and report back.

Watching my watt meter turn on the refrigerator.

Keep in mind all inverters have a surge rating.



I don't know what is actually doing this surge, it is either the deep freezer or the refrigerator. But it is showing on my circuit a 4x surge for less than 2 seconds.

Maybe get a Kill-a-Watt meter to see the surge happen.

The Kill-a-watt doesn't react fast enough to see the spike.

rayfound said:

The Kill-a-watt doesn't react fast enough to see the spike.

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Your 60-watt refrigerator, based on what my 120V thing did, should be perfectly fine on a 200w inverter (assuming a brief surge of 400w).

800w

jasonhc73 said:

Watching my watt meter turn on the refrigerator.

Keep in mind all inverters have a surge rating.

View attachment 6097 View attachment 6098

I don't know what is actually doing this surge, it is either the deep freezer or the refrigerator. But it is showing on my circuit a 4x surge for less than 2 seconds.

Maybe get a Kill-a-Watt meter to see the surge happen.

KILL A WATT Electric Monitor

Amazing deals on this Kill-A-Watt™ Electric Monitor at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

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It is that a full size fridge (~20-25cf)? If so thanks, I was guessing about 800w surge for mine but never checked it. Mine draw about 180w max with the compressor running. I'd like to try the little 400w inverter on it but am worried about all the control boards and gadgets my computerized fridges have.

jasonhc73 said:

Your 60-watt refrigerator, based on what my 120V thing did, should be perfectly fine on a 200w inverter (assuming a brief surge of 400w).

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For $16 I can give the 400W inverter SolarRat mentioned a try. If it doesn't work I'll have to make a decision how much effort I want to expend.

Can I make a suggestion? Just buy a Pure Sign wave with the highest wattage you can afford. Then later on, you will never regret it. I just bought a 300 watt Samlex. They make really nice stuff!

I mean I try that next... If a $16 turd will run it, I can do that and be done lol.

Webbee said:

Can I make a suggestion? Just buy a Pure Sign wave with the highest wattage you can afford. Then later on, you will never regret it. I just bought a 300 watt Samlex. They make really nice stuff!

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It's also not really about "affording" it, it's more about what is it worth to me to be able to run that bar fridge instead of bringing a cooler of beer or whatever. Since we still have a LP main fridge inside.

it is not really the size of inverter, it is more about the battery and cabling.
if the inverter is close to the fridge and the cable to the battery are oversized, there should be no problem.
But if there some length of cable between the fridge and inverter, and if the cable from battery to inverter are just bare minimum,
you could experience a failure.
also the battery shoudl be a model that is either beefy enough , or if small , able to deliver.
lead battery for car are from this type since they can usually output 10C (500A for a 50Ah battery), but LiFePo4 are usually limiter to 2C.

check out this little jobber.

rayfound said:

I mean I try that next... If a $16 turd will run it, I can do that and be done lol.

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On one of mine the battery lugs didn't want to get tight. I took off the back plate and found this. No big deal to tighten it up but just wanted to give ya a heads up in case you run into the same thing. Seems well built, but poorly assembled. Wonder if this is why they went on sale?

rayfound said:

The Kill-a-watt doesn't react fast enough to see the spike.

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Beau Larsen states that the peak is recorded.
But the seller says you can't go back and see the peak. You have to just watch it happen and record it in your brain-computer. ?

SolarRat said:

It is that a full size fridge (~20-25cf)? If so thanks, I was guessing about 800w surge for mine but never checked it. Mine draw about 180w max with the compressor running. I'd like to try the little 400w inverter on it but am worried about all the control boards and gadgets my computerized fridges have.

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Yes, regular full size. If you notice the Evergy Vue, before the appliance turned on there was already about 110 watts going, so 223÷2 it appears, 110w running after the startup.

SolarRat said:

On one of mine the battery lugs didn't want to get tight. I took off the back plate and found this. No big deal to tighten it up but just wanted to give ya a heads up in case you run into the same thing. Seems well built, but poorly assembled. Wonder if this is why they went on sale?

View attachment 6125

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No dice. It doesn't send the inverter into an error or anything, but the fridge doesn't start. It pulls like 400W for a few seconds (charging capacitor I assume) and then stops.

WSix said:

Robot Check

check out this little jobber.

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May try this next.

rayfound said:

No dice. It doesn't send the inverter into an error or anything, but the fridge doesn't start. It pulls like 400W for a few seconds (charging capacitor I assume) and then stops.

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Sorry man. That's surprising. Did you try it on other loads to make sure it's not a dud? I can't believe that little fridge needs such a surge. You are connected straight to a good battery right, not the cig adapter? The fridge was off for a while first to equalize the freon pressures (if it was already plugged in)?

Any updates on this? I've got a similar situation.

NickSpadaro said:

Any updates on this? I've got a similar situation.

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I've been without refrigeration for six years. Six months of the year is just fine just using mother nature and a cooler, the other six months I don't buy ice cream.

To run a refrigerator here, my plan is to first real world calculate what it would take to operate a compact, 12/24 vdc, 50 watt refrigerator then add the appropriate wattage of solar panels. There are quite a few reefers to choose from for this application so understanding performance specifications and finding any impartial performance reviews will be key in my decision making process.

At some point after I add panels and purchase the reefer, I will go from my existing 12 volt to a 24 volt battery configuration but that will require replacing my paralleled 12 volt lifepo's with either series compatible 12 volt lifepos, or if time allows, build a 24 volt battery bank with BMS and all the fixins using one of Will's tutorials. Fortunately, I only have about $250 invested in 40 amps worth of non series capable lifepos and I already know someone who can use them!

Of course upgrading to the more energy efficient 24 volt configuration will require a new inverter since my inexpensive but excellent, 12 volt, off the shelf inverter purchased from NAPA will no longer apply.

THEN, once I've upgraded to 24 vdc, I will still want to have 12 volts available to operate numerous and commonly found 12vdc items, which will require a step down convertor which sadly requires energy to perform the conversion, but hopefully the energy savings realized from upgrading to 24 volts for my inverter will make up for that plus, but I will have to calculate that to be sure. >> https://theinverterstore.com/product/24-vdc-to-12-vdc-step-down-converter-15-amp/

IN THE MEANTIME anything that I do purchase has to take into consideration the future.

Only fools rush in.

Peace.

Photo Below: Just one of many reefers I will be considering.

I have a small (3.5cf) freezer. I ran it successfully for months on a cheap WalMart EverStart MSW 750w inverter. Freezer draws about 1100W on start, 70W running, but the inverter worked fine. However, if the battery started to get even just a bit low, it would complain and alarm on surge startup.