Running fridge/freezer on inverter

We got our share of snow in my area and many people had an outage lasting quite a while. I'd like to be able to power a freezer on inverter powered from car battery for extended outages. My freezer takes

115W, 145VA to sustain operation, but the compressor is rated at 7.5LRA(locked rotor amps, which you can use to estimate your fridge/freezer's peak power requirement) and I guess that comes to 900 peak watt.

The 140W inverter I mainly use for charging digital camera batteries in my car definitely won't start this freezer, but my

700W(1000W peak) inverter can start it(barely.. it beeps when the freezer starts). Is there anyway I can run a freezer/refrigerator on an inverter short of getting an inverter with a peak wattage that can accomodate 120V
  • compressor's LRA? It's really foolish having to dedicate a 700W(1000W peak) inverter for a 115W freezer.

Searching the internet showed there's an "easy start kit" that lower's peak current by starting compressor slowly, but I haven't been able to find any.

I suppose I could use a series reactor to restrict the starting current but could the comrpessor start up with restricted starting current?

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You can buy lots of extra stuff and try to lower the amps or watt requirement for starting. I will bet that when you discover the cost of the soft start equipment it would have been cheaper buy a 1000w inverter. They are not that expensive. Besides it will give you something else to run when the freezer is not. I personally would not be to worried about a freezer when the temps are low. I had a power outage in Arizona ambient was about

100 F. I did not open it up until the power came back, 2 days. I kept a min max thermometer in it and it never rose high enough to be in danger.
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By the time you buy enough battery power to sustain the freezer for even just 8 hours and the charger to recharge it and the maintenance of having to replace the dead batteries every 3're much better off buying a nice genset that can power lots more stuff and has nearly zero maintenance just sitting there....

I recommend tossing caution to the wind and buying the Honda EU3000is super quiet, electric start at around $1800 on the net. It's a honey!

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It won't even come off economy speed crankin' that freezer..... With a 750W load, it will run 20 hours on 3.4 gallons of gas! Mine does, easy.

Larry W4CSC

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Larry W4CSC

Why not buy a generator? That way you could power other things during a power outage and every so often, you could plug the fridge in to build up the cold in it.

-- "The militia, sir, is our own ultimate safety. We can have no security without it...The great object is, that every man be armed...Everyone who is able may have a gun." - - Patrick Henry

Reply to
Larry Dugan

Man, there's no such thing as 'cold'. cold is simply the absence of heat. Therefore you should say plug in the fridge to remove the heat inside :) anyway I didn't mean anything... just said it for fun.

Well, about inverters... wasn't there a thread recently about powering motors with inverters? You need a sine wave inverter to power that fridge's compressor motor well. Some sine wave inverters even come with start up functions to start your fridge. Alternatively you could place some capacitors across your motor's load so that it starts up slowly protecting the inverter :)

Reply to
Brian Su
20 hours on 3.4 gallons!!!Even a tank at full speed doesn't consume so much.Better buy nothing, save the money because power outages happen every now and then.Do you have a lot of goodies in the freezer?

-- Dimitris Tzortzakakis,Greece Visit our website-now with air condition!

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Reply to
Dimitris Tzortzakakis

M1A1 60 gallons per hour cross-country (1200 gallons in 20 hours).

*Idling* it would use 200 gal. in 20 hours.
3.4 gal of gas costs just a few dollars, what are you talking about?

Best regards, Spehro Pefhany

Reply to
Spehro Pefhany

Not in Greece it doesn't....(c;

Larry W4CSC

Reply to
Larry W4CSC

Say EUR0.80/l * 3.8 (US gallons) * 3.4 ~= EUR10. I doubt you can get a bottle of Ouzo for that. ;-)

Best regards, Spehro Pefhany

Reply to
Spehro Pefhany

Who said I need to sustain the freezer on normal cycle? I need to sustain the tempreature low enough to prevent spoilage of food inside.

A freezer can often keep it below freezing for a whole day, but being able to run the compressor every 12hrs or so for 30min is going to help quite a bit. We seldom have power outages lasting more than a few min. It will not be powered from a dedicated battery bank. The inverter will simply get hooked up to my car and fridge will run with the engine running.

This freezer only takes 115W nominal, so input to inverter is about 140W or

12V 12A.

If I run it on a fully charged car battery for 30min, it will use up 6Ah from the battery and that amount houldn't interfere with the ability to start the vehicle.

Once I do this, I can just do this again after I used the car so the battery is brought back to full charge.

This isn't correct about a gasoline powered generator. Ever had trouble starting a lawn mower that was stored until the next season by simply putting it away normally?

Gasoline don't keep very well and it's known to gum up the fuel system.

Oh please. There is no way I'm going to justify spending nearly two grands for rare power outages.

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Amen to that suggestion. Most of us seriously interested in both heating/lighting our homes and running our refrigerators/freezer have many years back purchased at least a minimal generator system.

I really can't imagine any responsible person attempting to deal with these power outage situation by employing what amount to some sort of a kludge solution.

Then too, my home and family mean a great deal to me, so when my youngest daughter was born prematurely, I spent enough bucks to assure that the home environment would never become a health issue.

Harry C.

Reply to
Harry Conover

Many RV owners run apartment size refrigerators on inverters. The duty cycle of a refrigerator is low enough that they can get by with just a few batteries. However, they use deep discharge batteries, often 4 golf cart types. Deeply discharging car batteries drastically reduces their life.

You don't need that size for a freezer. Honda makes a nice 1KW unit that sells for about $700. It is a DC generator that drives an inverter.

For your use a Coleman 1.8KW unit for $500 would be adequate.

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Just a thought that I've had before:

If your power outage is due to SNOW and you're trying to keep things cold why don't you put it in a box outside in the snow? Here in the northwest we've had a few outages that lasted over a day with temperatures in the teens and twenties. I just put the frozen stuff in a box outside. Refrigerated stuff had to be cycled into the garage which was cold but not freezing.

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I have an old BorgWarner fridge/freezer (remember those)that still works. It pulls 350w running and about a 1k to start. cycle time is around 20%. My 700w Vector MS will start it with a little hesitation. You'd need a lot of capacity for large fridges, but newer smaller ones run as little as 120w. So even a medium battery bank of

1000ah will only last a few days.

If its cold outside, thats an option. The second option is dry ice. Third is a gen.


Reply to
Martin Riddle

Ouch! That hurts!

Larry W4CSC

Is it just me or did the US and UK just capture 1/3 of the world's sweetest oil supply? What idiot wants to GIVE IT BACK?!! Let's do what Europeans have been doing for centuries. DIVIDE UP THE SPOILS OF OUR CONQUEST! Gas will be $US0.50/US gallon again, STUPIDS!

Reply to
Larry W4CSC

Yep. That's EXACTLY why every pilot of every gas-powered small airplane ALWAYS fills his tanks to the brim and runs his carbs dry BEFORE hangaring the airplane. If you did that with the lawnmower, you're problem is OVER!

Out in my sheet metal storage building is a 1988 Honda EG5000X 5KW gas genset with a steel gas tank on top of an 11hp Honda slant 1-cyl engine with float carb. I bought it cheap from two lawyers after the power came back on after Hurricane Hugo, vowing NEVER TO SIT IN THE DARK AGAIN.

The day I got the genset it had about 12 hours on it. I changed the oil and brimmed the gas tank with regular old 87 octane from Speedway. This was in 1989. It has sat there in that 130F summer, 25F winter uninsulated storage building since 1989, except for a few Ham Radio Field Days and local power outages.....

I don't use the little gas tank on top of the engine to run it. I took a brass air manifold, made for fishtanks, that has a common rail and two tiny valves and inserted it into the gas line. The common rail goes to the carb. One valved "outlet", now an inlet, goes to the on-genset tank. The other valved inlet goes to an 8' length of plastic gasline that's open on the other end. Whenever I have to use this genset, I simply put a plastic jerry can on a step or chair above the carb which has no pump. I lay out the gasline in the grass and open both valves, filling the line with gas from the onboard tank. When gas comes out, I shut off the onboard tank fishtank valve, pinch the hose to keep the gas in it and stuff it down into my jerry can so it siphons gas directly from the jerry can into the filling. When this jerry can gets empty, I pinch the hose, pull it out of this can and plunge it into the next filled can.....never shutting off the genset to fill it.

The gas in that metal tank on top of my Honda EG5000X is still about

90% gas from 1989. It is refilled to the top before the genset is stored and the carb is first run dry by the engine then the float bowl drain is opened to drain the carb of any residue gas that may evaporate just sitting there......

Stop by the house and I'll start that genset with 1989 gas on the FIRST PULL. Bring a $100 bill and we'll make "bad gas" discussions even MORE interesting!

Now why does this work like this? I need "gas stabilizer" or some other "diesel-fuel-in-a-can" at $70/gallon, don't I?............Nope.

I play a lot with other people's yachts here in Charleston, SC. My current project is a very nice 1985 Amel Sharki 41' cruising ketch belonging to an English friend of mine who lives in Atlanta. It's his boat. I just spend his money on it. Nearly every boat in any marina around here has fuel problems, gas and diesel. None of it is necessary. All they had to do was FILL THE TANKS even if they aren't empty....when storing the boat for over 5 days. They're all lazy....

Let's take a half-empty 10 gallon gas tank. Half the tank is filled with liquid gasoline, an odd concoction of heavy elements, like the shellac you see on the mower's carb throat, and light elements like octane which gives gas that special explosive zip when the plug goes off. The heavy elements pretty much stay in liquid form. These are the same elements diesel fuel is made of. But, the light elements try their DAMNDEST to escape the liquid we forced them into in the first place at the refinery. (Note how gas "evaporates", actually vaporizes into a gaseous state so it'll fire.) That's EXACTLY what's happening in that half-empty gas tank. The light elements vaporize until the airspace above them is SO saturated there isn't even enough oxygen left in the tank to make it explode! (Remember that trick of throwing a lighted match down the gas tank opening in high school? The match can't burn inside the gas tank's heavy vapor. The mixture is WAY too "rich" in fuel vapors to support combustion. Gas tanks don't explode in accidents UNLESS you crack them OPEN to let the oxygen mix with the gas....except, of course, in movies.


Ok, so here's our saturated gas tank, half filled with gas, half filled with VAPOR. It's morning (yawn). Temp is 40F, the sun rises, raising the temp higher and higher. If the mower is in a lawn building, it might get to 130F by 3PM, really HOT! No matter if it only goes up a few degrees, that damned vapor EXPANDS and causes quite a pressure if the gas tank is SEALED with no vent. Not to worry, mower gas tanks all have open vents to prevent pressurization. The expanding VAPOR, laden with all those LIGHT elements that give the gas its zip (octane rating) are pushed out of the tank all day.

The sun's getting colder outside. Dew has formed on the lawn, on the lawn building, whatever gets cold first....or didn't get warm enough, like our gas tank full of EVAPORATING (cooling) gas. The evening air is LOADED with water as it cools. It condenses on anything. Now, back in the tank, the gas is cooling nicely, as is the VAPOR on top of it. Just like it expands, VAPOR really contracts, causing quite a vacuum inside the tank. Not to worry, the open vent sucks in cool, MOIST outside air to replace the vapors that were pushed out during the hot day. Oh, oh....wait! The moist air looks like it's forming a tiny film of WATER on the INSIDE of the cold steel tank! Look! A few of those droplets have touched and a tiny rivulet of nearly invisible water slowly falls down the side of the tank. Gas is lighter than water, so the little drop of water goes UNDER the gas to puddle up around that OUTLET PIPE on the bottom. What crap is this? Water comes IN THE GAS, doesn't it? No, water COLLECTS inside EMPTY GAS TANKS this way! Now we have "WATER IN THE GAS" and will go storming off to protest at Sunoco to the stunned employees. It wasn't their fault. There's little or no water in their gas.....mostly.

It's after sunset. The water in the new air inside the tank condensed on the tank and ran down it.....OR....the government-sponsored, alcohol-based, corn-farmer-PAC-lobbied, greenie-loving, GASOHOL they forced us to use DRIED OUT THE NEW AIR because alcohol ABSORBS WATER....a real problem for the gas-powered boaters in the ocean! More water collects around the intake pipe.....dammit.

Also, now we have a vapor space above the gas in the tank that is NOT VAPOR SATURATED. All the while the air is being slowly sucked into the tank......those light element vapors that give that gas the zip are BLEEDING OUT OF THE LIQUID GAS INTO THE NOW UNSATURATED AIRSPACE YOU LEFT above it.

GO BACK UP TO "REFERENCE POINT" and read from there to here, over and over and over, for every day in the life of your HALF FILLED LAWN MOWER, outboard motor, generator set, stored old car, and every half-filled gas can in the shed......

What's left in the tank after 6 months? Heavy elements......looks like shellac......smells like shit! You turn to the wife who's been pumping on the recoil starter of the old Sears mower and declare, "The gas went bad because gas goes bad if you just leave it sit all winter."

The gas "went bad" because you didn't FILL THE TANK SO IT COULDN'T BREATHE EVERY DAY!!!


Polyethelene gas tanks are made of Polyethelene molecules which are HUGE, as molecules go. In between these beasts are GAPS big enough to drive a LIGHT GAS ELEMENT MOLECULE (that gives gas the zip) through! Didja ever notice how a completely SEALED plastic gas tank "smells like gas", no matter what you do to seal it? It's called "migration" and every plastic gas tank has it. Even a FULL plastic gas tank slowly, but surely, leaks those ever-important light molecules.....not as fast as the half filled gas tank above here, but they leak.

The only good poly tank, is a TOTALLY EMPTY poly tank. Gas goes "bad" in poly tanks and you can't stop it. Lucky for you, poly tank vents can be SEALED to keep the air out when there are NO GAS VAPORS in them. Leave them empty and vent all the residual vapors out of them before sealing them up for storage so they don't act like pipe bombs.

If you'd like to STORE gasoline for your emergency genset, be SURE its done in a very full STEEL tank old hardware stores still sell because they are BEST. Mine is a 55-gallon steel DRUM, filled to the brim and sealed. Gas in it is about 5 years old and smells just like the day I filled it....same idea as above.....(c;

Larry W4CSC

Is it just me or did the US and UK just capture 1/3 of the world's sweetest oil supply? What idiot wants to GIVE IT BACK?!! Let's do what Europeans have been doing for centuries. DIVIDE UP THE SPOILS OF OUR CONQUEST! Gas will be $US0.50/US gallon again, STUPIDS!

Reply to
Larry W4CSC

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