Converting 110v House Refrigerator to Solar Power!

[gadgetman]

 Now that I have a good solar system installed. I am going to convert my 110v only house fridge to a 12v marine chill plate system. I have decided in a Seafrost unit. They seem to make the best one out there and will custom make cold plates for it. They use a nice stainless plate with the coils between them and a Danfoss 12v variable speed compressor. It will require cutting a hone in the fridge to get the lines out to the remote compressor. Today I drilled the hole !!! Yea I didn't hit anything but sure came close to a capillary tube !!! oops !!!

Once installed the unit should draw about 5 amps with compressor on high, on med speed it will be about 3 amps. The solar should handle that well. I will post some pictures once I get the unit and actually start installing it.

I am getting ready to add a second battery bank but not sure where yet ! Dang space sure is limited. I will likely try the fridge out with the one battery bank which is 200 ah and it may do OK.

A solar fridge will be kewl, wont take anything from my battery if the sun is out at all. Even on a cloudy day i can reach about 9 amps

Cant wait for the unit to get here.

[ibdilbert01]

Hope to see pics of this!  This sounds like a fun and rewarding project! 

[gadgetman]

Here are some pictures of the old fridge which still works on 110v

I had a cold plate 12v compressor system built that would slide into the shelf area. Then will remote mount the 12v compressor to the old compartment that use to hold a propane heater.

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Almost hit that tube !


Here is the back of the fridge
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The compressor will be on the LS behind the wall where the old propane heater was. Which is a solar controller/electrical area now.


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Holes for 4 in exhaust and freon lines.


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Old Heater box. The old heater exhaust hole was used to add an outdoor 110 plug.


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More to come when the plate arrives !

[ibdilbert01]

Fantastic!   Can't wait to see more pictures!   

[ClydesdaleKevin]

I wonder if this conversion would work on a small deep freezer?  Would love to get some hunting in again some day, but not much room in the RV freezer for meat...hmmmmmmm....

Kev

[gadgetman]

Yes, you can make a freezer if its insulated well enough and its small. I will actually have a freezer section on the top side of the plate. It will be installed about 8 on off the top. So the top section/shelf will freeze stuff.
I will just need it to keep stuff frozen or make ice cubes. That works too if you use metal ice trays. Remember those ?

[gadgetman]

Well the box arrived  
This is the cold plate. The box on the back is the expansion valve and the lines
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This is the plate  in place to check the fit. The lines are uncoiled and a helper fed them thought the hole in the bottom of the fridge as I bent them and routed them across the back of the fridge.

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The 2 copper lines are in the black foam across the back of the fridge and then through the wall to the old heater box area. The white pipe next too the orange  brake filter is a through hole to the inside of the unit with a cover over it. This will be used for a propane quick disconnect for the new heater inside. (that's later). Thought I would throw the pipe in there now. We use that fitting for a grill now.


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This is the compressor unit with the service cover off. It vents the hot air to the vented area behind the fridge. There is a fuse box added to the this area with 8 gauge wire for future use. The compressor is on a main switch at the ft of the fridge and a 15 amp fuse.


There is a control panel to set the speed of the compressor at high 5.4 amps   med 3.5 amps and low speed at 2.6. This should help manage the batteries if needed. I have 30 amps of solar now. The sun will pretty much run it during the day. I just have to manage the nights with the one battery bank. That 12 hour period shouldn't be more than a 50/50 duty cycle. That's  about 30ah on high. Should be able to manage that




I turned the unit on and let it run for 1.5 hours. It started at 85 deg and was at 41 when I check it with a temp gun at the center of the fridge. Here is the plate frosted.


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Tomorrow I will test it some and see how it does once its been cold awhile. So far though it seems like its is going to work real well. It wasnt cheap but it was still less that a new RV one and now I have a Hybrid Fridge

[gadgetman]

Well I reached a limit of sorts. Maybe you can see the pictures here.

http://www.classicwinnebagos.com/forum/index.php?action=mgallery;sa=album;id=417

[ClydesdaleKevin]

So I have another question for you.  A lot of folks here are on a pretty tight budget, and we have a lot of friends at the Renaissance faires with vintage RVs as well.  Quite often when you buy a vintage RV, some previous owner has changed out the stock gas/ammonia fridge with a household fridge.

Fixing a gas/ammonia fridge is often just a matter of burping it, or fixing it relatively on the cheap.

But if the fridge is missing and replaced with a household unit, then the only two solutions are to find a new RV fridge, or do the conversion that you did.

So here is the question...how much did this project cost you, parts and all?  I would be really curious to know if this is an affordable alternative to buying a new or used RV fridge for those on a really tight budget.

Kev

[gadgetman]

The unit cost me 1200.00. Spent about 50.00 in wiring. Replacement fridge for my unit was about 1700.00. Granted I could of bought one for maybe 1200 but then It wouldn't be solar   Lets see, the price of the 110v fridge hmmmmm 12 years ago was about 350.00. All in all about the same as a amonia unit would be.

You could use a Norcool plate system too. Theirs mounts to a wall and they use "their own" compressor not a Danfoss. They have no charge valves on them for service either. If you call Norcool and need the freon spec you get no help. Their units are about 600.00 and I cant say I have heard anything really bad about them. I just wanted the Danfoss compressor and a shelf plate and not a wall plate.

If you have solar its a great way to go. No flame and dont have to be level either. Solar pretty much runs it during the day if you have enough wattage.

[ClydesdaleKevin]

Good to know.  We had a household fridge in our current 89 Holiday Rambler when we bought it a couple of years ago.  We found a rebuilt Dometic 2-way, 9 cubic feet, with rebuilt coils and new circuit boards, at a small RV fridge shop in Charlotte, North Carolina.  Total cost was 850.00 plus tax...and it looks and works like new, with a better-than-new 5 year warranty.

The reason I mention this, cost and all, is that we boondock a lot in the winters now.  Currently we only have 65 watts of solar from a single Kyocera panel, feeding 4 deep cycle golf cart batteries.  This will be upgraded to 300 watts feeding 6 batteries before winter.  But even with our single small panel, we successfully boondocked for over 2 weeks, with more than ample power to run the RV fridge off the batteries and propane, running the generator for 1.5 hours at night to recharge the batteries to full capacity.

I'm just trying to put it in perspective and weighing the cost of the conversion versus a stock fridge, and using no propane at all versus using the very small amount of propane that a fridge uses while boondocking.  An RV fridge using a very small amount of propane when running off of shore power, with the batteries providing the 12 volts for the circuitry.  And the amps drawn to run the circuitry is considerably lower than the amps drawn by the cold plate.

So if you were running an RV completely without propane, I guess I could see doing the conversion.  Say, an alcohol stove and solar hot water heater.  But if you are using propane onboard anyway to run other systems, I'm not really seeing the benefit of the conversion versus an RV fridge, given the very small amount of propane used by an RV fridge, and the very small current draw used when in propane mode.

It is a very intriguing project though.  Glad you are thinking outside the box and experimenting with other alternatives.  Ingenuity is a beautiful thing, even if the conversion isn't for everyone.

Kev

[gadgetman]

The project really started because I wanted solar. Once that was in it was the LED lighting to help the solar. Then it was hmmmmm now I only have a 110v fridge. So for me it wasn't the cost of the propane so much as it was trying to make what I have work.

Replacing the fridge with a RV one also required my entry door and the framing to be removed. Or a ft side window. Neither was looking like much fun I tend to over due things  but that's just me   Like 520 watts of Solar. Blame it all on the solar !!! That's what started all this. I started with 260 watts and then found out I get the 30% tax credit for solar........OK I ordered another 260 watts ! Thanks Sam ! With 520 watts even a cloudy, shady day will put out 5 to 9 amps.

I ran its first test yesterday, The air temp in the coach was 98, the fridge was 75 when I turned it on high. After 2 hours it was at 45 deg. It ran from 10:30 till 5 pm when I left and the temp was 41. I turned it down to med speed 3.4 amps and left it on. This morning it was 38 deg and the compressor was off when I checked it.

Today should be a good test as temps will be higher outside. I may install an hour meter on the cooling fan circuit just to see how many hours its running in a day with the stat set at 4.

All in all it seems to have turned out well.

[ClydesdaleKevin]

Now that I think about it, you know where a conversion like this would really come in handy?  A solar house or cabin!  Gas/ammonia fridges have to be vented on the back and roof...so its not always doable in a house or cabin unless you want to cut holes in the walls and roofs.  But if you were to go full solar on a house or your hunting cabin, this conversion would allow you to have a 12 volt fridge ANYwhere!

It would also be great if you were remodeling the interior of an RV and wanted to relocate the fridge without having a side and roof vent...or on a boat for the same reason...then you could put the fridge anywhere.

So while its not cheaper, it does have its place now that I think about it.

Thanks for posting this thread!  Its pretty neat!

Kev

[gadgetman]

These systems were made for boats just for that reason, put a fridge anywhere and for the fact that propane and boat hulls dont mix well

[wrolandhyattjr]

There's another way that I am taking.  I am taking out my 6 cu. ft. Dometic  RM 3663 3-way, which is subject to a recall, anyway. I am installing a newly engineered Norcold 7 cu. ft. AC/DC refrigerator.  These are normally marketed to the marine market and to a lesser extent, to the over-the-road truckers.  It uses a Danfoss compressor refrigeration system, highly regarded.  The older Norcold AC/DC units used a proprietary system which I'll not go into.  Enough said that the new danfoss system is an outstanding step up.  The unit uses about .4 amps AC and 3-4 amps DC.  A decent solar system will handle it nicely and the user will no longer be held hostage to the propane bandits.  The refrigerator can be had for about $1200 - a lot of money - but really no different than a fairly inexpensive - and inefficient - gas/electric unit.