PROBLEM: Dorm fridge won't run on 1000 watt inverter

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concretebox

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My RV fridge went out and I replaced it with a Haier HCR27W mini-fridge. It runs fine on shore power, but it overwhelms my inverter. What's my solution? A higher wattage inverter or another brand? A new, higher-quality house battery or do I just need to bite the bullet and buy a replacement RV fridge?

Here are the specs of my set-up:
House Battery: Walmart Deep Cycle Marine Battery.
Inverter: Cobra SPI 1000 watts.
Fridge: The manual says 115volts, 60hz, I can't find more specific info on watts.
Wiring: I've got a heavy gauge copper wire running about 20 feet from the battery to the inverter. The run from the inverter to the power supply is less than two feet, standard household three-prong wire.

The inverter runs the TV, Xbox, phone charger and lights just fine.
 
D

Donedirtcheap

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Go with 4 - 6 volt deep cycles, a 3000 watt inverter (a good one $1500.00), 4 -130 watt panels and an mppt charge controller and back it up with a 2000 Honda. I love my RV propane frig.
 

SoulRaven

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From what I've read about inverters, your problem might be that your inverter isn't close enough to your battery.
 

minimotos95

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all i found is that the fridge isn't energy star qualified. your average house 15a outlet is roughly 1700w so just assume the fridge needs all 1700w until you can get it on a kill-a-watt. your inverter does have overload protection, do you know if it's tripping?
 

Optimistic Paranoid

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A couple of general comments.

Inverters need to be as close to the battery as possible. The AC wire can be long. The DC wires need to be short.

Inverters have two ratings a start rating, and a continuous duty rating.

The start rating is the maximum power it can put out for a short period of time. To start a motor turning, for instance.

The continuous duty rating is the max amount of power it can put out all day long.

The manufacturers always advertise the higher, starting power. So a 1,000 watt inverter can put out 1,000 watts for 15 or 20 seconds, and after that, it will fall back to only putting out maybe 750 or 800 watts continuous duty.

Dorm refrigerators are cheap because they are built cheap. Dorm refrigerators were not designed to be bounced around over rough roads. The compressors in them expect to be level when they are run. They often have a very short life in vehicles.

Regards
John
 

Zil

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Marine batteries are compromise of starting and deep cycle. Not good at deep cycle. 1000 watt is not enough inverter to start-up refrigerator.
Short heavy 12 volt wires. Short heavy 12 volt wires.
 

VanLifeCrisis

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I bet the inverter is strong enough, you need to put a thick short wire from battery to inverter, and then run the extension cord to your fridge. I have a big ole dorm style fridge, but supposedly very efficient, and it taxes my batteries..i have 215 amp hours deep cycle(half usable) , a cobra 800 inverter, and they need to be charged every 4 days if i have no solar.


this is the fridge i have, tho i think i would prefer a smaller one for van life. I hate how they make actual power usage hard to figure out on these things when shopping..
http://www.sears.com/kenmore-3.1-cu...p-04695693000P?prdNo=2&blockNo=2&blockType=G2
 

Optimistic Paranoid

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DazarGaidin said:
I bet the inverter is strong enough, you need to put a thick short wire from battery to inverter, and then run the extension cord to your fridge. I have a big ole dorm style fridge, but supposedly very efficient, and it taxes my batteries..i have 215 amp hours deep cycle(half usable) , a cobra 800 inverter, and they need to be charged every 4 days if i have no solar.
I tried looking this thing up online, and all I could find was that it was NOT energy star efficient. The Chinese manufacturer doesn't list the amps or watts anywhere I could find. Which makes me suspicious that it draws a hell of a lot of power.

Regards
John
 

VanLifeCrisis

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Well if you can bite the bullet, the best option is probably a 12v fridge. Unfortunately i cant bite that bullet and live right now lol
 

SternWake

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Inverters should Always be as close as possible to the batteries, without being in the same compartment. There is little voltage drop on AC/ household wiring, so always use AC extension cords to device from inverter. Do not bring the inverter to the device.

And thick cabling is a prerequisite even at short lengths.

While Moving the Inverter closer, and using shorter thicker cabling 'might' solve the issue of overcoming the compressor start up surge, it might not.

The start up surge can be 10 to 15 times, or even more than the actual amperage required to run the fridge after the compressor gets going. I know of one guy who got a Dorm fridge and it would not run on an 800 watt inverter, so he bought a 1200 watt inverter. Still no go, So he returned it and bought a 1500 watt inverter and this worked. So he filled his fridge and went away for the weekend, and was awoken at 4:30 AM by the low voltage alarm on the inverter the first night, and had to go out and buy a cheapo cooler and ice just to make it through the weekend..

Now he only turns the fridge on if he can plug into the grid, and wishes he had just bought a 12v compressor fridge to start with.

Little thought is given to the efficiency of most of these Dorm Fridges. They are marketed under the " if they are cheap enough, Americans will flock to buy them!'

And sadly, this strategy still lines their pockets because the lowest number next to the $ is all some can ever see.
 

SoulRaven

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This type of messy problems is exactly why I opted to go with a 7 day extreme ice chest rather than replacing my powered fridge when it died. By using the big blocks of ice, they'll last nearly a week and there is virtually nothing to go wrong with it. If for some reason I can't get block ice, regular bagged ice will work too, just not last quite a long.

I made a conscious decision to not need AC power in my camper van.
 

compassrose

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http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/

This article should help you sort out the battery situation. I suggest bookmarking and studying the whole site. Like others have said, put your inverter as close to your battery bank as possible without putting it in the same compartment. Only batteries should be in your battery compartment. You need to add at least one more battery to your bank. Dorm refrigerators, like most residential refrigerators, do fine bouncing down the road. At least all of ours have.

Buy or borrow a killawatt meter. You have to measure. A killawatt from Home Depot costs $20 for the plain basic meter and $30 for the fancy one. We got the fancy one because that is what our store stocks. It's surprising what things actually use in power.
 

concretebox

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So it's been five months...I've been thinking a lot about this fridge problem. I haven't been living in the RV for the last few months, but I'm about to move back in and take it cross country. I'm thinking of selling the fridge and using a 7-day cooler as suggested.

My cheap walmart deep cycle battery is kaput. About $75 to buy a new one. Even so, I don't think it will run my fridge very long. I looked into upgrading to a higher quality battery plus what I would need in solar to run this fridge. I could buy a 12volt fridge for less. Even a 12v fridge is too costly for me now.

Without the fridge my power requirements will be much more manageable. The most power-hungry will be the Xbox, then the TV, then the rest: lights, a blender, a waterpik, and chargers for phone, tablet, laptop and e-cig. Without the fridge I think I can run everything on a $75 walmart deep cycle battery and charge it with a $185 Renogy 100W panel kit.

So I guess my only question remaining is how much do I have to spend on a cooler?
 

GrayWhale

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You should check my thread on using a small, dorm size freezer instead ($143). It uses the same wattage as your dorm fridge, around 120w startup and leveling down to 70w. I only run it on a timer for 2.5 hours a day on level "4.5" out of "7" max. Two 1.5 liter water bottle gets frozen and keeps everything cool when it's off for 21.5 hours. On ice power, it works just as good as my Igloo MaxCold cooler ($40).
 

highdesertranger

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well I saw a side by side test on ice chest and the coleman extreme and igloo max performed almost as well as the high end coolers that cost 100's more. if it was me I would do everything possible to get a 12v refer set up. highdesertranger


ok now I just saw another thread and you said you were getting a new battery and solar. please get a 12v refer. if it was me I would sell the xbox and all the games and buy a refer. highdesertranger
 

GrayWhale

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highdesertranger said:
ok now I just saw another thread and you said you were getting a new battery and solar. please get a 12v refer. if it was me I would sell the xbox and all the games and buy a refer. highdesertranger

I don't have an Xbox. I agree that a 12v refrigerator is the best. But as a part timer with electric hookup 80% of the time, I really don't want to shell out $800 for a nice 12v one vs. this freezer that was only $143. Selling it will probably get me $70 or $100 if I'm real lucky. Buying a used 12v would be rolling the dice at usually, a $400 used price, for something that may be problematic or about to conk out real soon. This $143 freezer is really working well. My $70 HB 2-stroke generator runs it fine too.

Even on battery, it's only timed to go on for 2.5 hours a day and of these 2.5 hours, the compressor only kicks on some of the time and nowhere close to running constantly at 70-80w during these 2.5 hours. And it's a lot colder than a 12v.

Another worry is that an $800 12v refrige would make it the most expensive thing in my van should someone breaks in an steals it. It's so compact and easily carried away. Whenever I stop somewhere, my laptop, GPS, radar detector, tablet, phone, etc. are always in my backpack. And they don't even add up to $800.


highdesertranger said:
well I saw a side by side test on ice chest and the coleman extreme and igloo max performed almost as well as the high end coolers that cost 100's more. if it was me I would do everything possible to get a 12v refer set up. highdesertranger

I was very shocked by how poor my Igloo MaxCold was. As I recall, I had three full, 2L soda bottles that were completely frozen solid and about 5-6 little water bottles, half full and frozen. After about 2 days, the big bottles were almost completely melted and the small bottles were warm water. This was on hot summer days in the East Coast.

The $143 dorm freezer was in the same van and it did just a little better, however it started off at a colder baseline so it had an advantage. I didn't feel like taking the effort to make it perfectly equal due to the hassle involved. But found that this cooler was a huge waste of space when the Dorm Freezer did just or almost as well as a cooler, when it's off. I was already suspicious of this Igloo from the first time I used it and saw how fast ice melted. Nothing close to the "6 days" it claims. And this is with a cooler packed mostly with ice bottles only and opened about 2x a day. Bags of little ice cubes would melt even faster.
 

concretebox

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High desert ranger,

A used Xbox360 and games wouldn't get me close to the amount needed for a 12v fridge. It has much more value to me as entertainment. Games are one of my hobbies. I'm guessing you're not into games, so imagine giving up one of your favorite hobbies.

On another note, I'm now thinking of keeping the fridge for when I do have shore power and using it as a cooler when boondocking. After reading HandBob's blog on solar, I'm less convinced that the fridge on battey combo is impossible. I may need to supliment the fridge with ice and supliment the solar with my generator (which I already own), but I think it can be done. I'll be running some tests before I leave home base though.
 

highdesertranger

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ok sorry you guys I got you two mixed up. you know you can get that wynter(spelling) that bobs been posting for under 500 bucks from home depot. if you are going to buy an ice chest you can deduct that from the price to make it even cheaper. highdesertranger
 

MikeRuth

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Off Grid 24/7 said:
This type of messy problems is exactly why I opted to go with a 7 day extreme ice chest rather than replacing my powered fridge when it died. By using the big blocks of ice, they'll last nearly a week and there is virtually nothing to go wrong with it. If for some reason I can't get block ice, regular bagged ice will work too, just not last quite a long.

I made a conscious decision to not need AC power in my camper van.

Which Chest did you actually purchase?
And I trust you seem satisfied with it?

Thank you,

Mike R
 

GrayWhale

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MikeRuth said:
Which Chest did you actually purchase?
And I trust you seem satisfied with it?

Yeti is probably the best cooler, but they're about $250-600, depending on which model. My Igloo MaxCold is supposed to be good for 5 days at 90 degrees, but barely make it past 2 days with solid 2-Liter ice bottles, which lasts way longer than bags of ice cubes.
 

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