Apartment fridge install

[SternWake]

Some have figured out a way to have the fridge thermostat fire up the inverter when it is ready to fire up the compressor and elmininate most or all of the standby draw.

I am not sure how this is done but it would go a long way on saving battery power. NOthing worse than wasting juice doing nothing but waiting for something to switch back on.

 

[tx2sturgis]

Some have figured out a way to have the fridge thermostat fire up the inverter when it is ready to fire up the compressor and elmininate most or all of the standby draw. 

Great idea...I will look into that option if/when I go back to RV life.

I assume you would tie in a relay to control the inverter power switch, the relay activated from the simple mechanical operation of the internal thermostat.

One other advantage of the dorm fridge: ZERO complicated electronic control circuits.

Nothing worse than a perfectly good appliance that blows a computer circuit board in 5 years and you cant get a replacement, anywhere.

 

[Sabatical]

The dogs let me sleep til 7 this morning. Good puppies. The sky was light but not much power coming in via solar yet. AH reading on the whiz bang jr says 207. A loss of 5ah in 12 hours. It was a cool clear night, low 50's i think.

SW, i've read about the control circuit you mentioned. It's a great idea, but requires an inverter that is remote switch capable. This cheapy Bestek is not. It's future replacement will be, and at that point i'll put one of those circuits in. One of the selling points for me on the Morningstar was it's ability to go to sleep when it had no draw. I am bummed that it won't work in this setting, but that's $250 i can use elsewhere.

T2S, i'm gonna look for an attic fan control and see if that is feasible in our camper. Can i run a 12v computer fan with it? I'd like to see a passively cooled setup here and maybe that's possible. I could block the low side vent as you did and neck down the opening for the roof vent. Then add vent holes in the side trim around the fridge and see what happens. I would think there should be a convection current, but would it be enough. Maybe adding a computer fan in the vent with a switch in the cabin would work. Lot's to think about here.

All input is appreciated. I've got to work on firewood today, but i'll post tonight after i have a total ah reading from the days charge cycle.

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[jonsun]

I'd think there is a difference when the fridge is being shipped and abused, versus actually having the compressor  running and being bounced around.  They might be susceptible to being run a few degrees off level as well.


BUt we do not really have enoiugh data to say whether the residential fridges do or do not handle the bouncing around in actual use.

I feel these residential fridges were not really made with efficiency in mind, and when run on an inverter seem to typically double the electrical consumption of the much more expensive 12vDC compressor fridges.

Much of this would depend on inverter efficiency and standby current.

My 800 watt MSW inverter draws 0.68 amps turned on powering nothing.  My 1.8 cubic foot danfoss averaged 0.62 AH per hour over 3 days in ~70F average ambient temps the last time I stuck my wattmeter on it.

So my MSW inverter turned on powering nothing, nothing even plugged into it,  uses more battery than does my 12v fridge, most of the time.

I view the inverter as Evil, a necessary one, that I rarely employ unless there is no other option.

there are people on youtube and other forums that have been running them for a while. but the thing is you take a more typical size fridge of 1.3 - 2.7 or so cu/ft and they're $70-100. You can go through 5-6 of them to every one 12v fridge. And I bet problems t might arise likely come from either loose solder or broken brazing joints, both of which wouldn't be hard to fix.


and given that it just pulled 5a over 12hrs it's looking like the guys 30A a day from a thread last year might actually be normal. can't wait to see.

 

[tx2sturgis]

Those readings are encouraging I think.

Is the fridge still cooling just empty space or is it loaded with food?

I suspect the current drain will go UP noticeably if you load it with room temperature items, and maybe even down for a time if you can load it up with cold items and especially pre-frozen items in the freezer. It might still be trying to chill the air inside, and I'm assuming you have opened and closed the door a few times during the testing.

BTW, what IS the temp setting you have it set for?

Yeah I would see no reason why an attic fan thermo switch would not work for a small computer fan or blower. They are rated for several amps, and are just a simple bi-metal cam operated set of contacts...nothing fancy, but not much can go wrong either. I personally would not want a fan on a manual switch, I will either forget to turn it on, not think about turning it on, or leave it on all the time accidentally and ventilate all the cooled and heated air inside the camper.

BTW, it might not 'self-clean' on low voltage DC...so it might work for 1 year, or it might work for 250 years!

The reason I used a 120v duct booster fan was that they are quiet and simple, and are designed to work in a high heat environment. They are not affected by, nor do they affect, nearby high power ham radio transmitters and receivers. Plus it was easy to use it with some 4" flex tubing running up to the fridge vent on the roof.

But there is no reason a computer fan would not work.

Have you worked out the way to hold the fridge in place yet?

As I mentioned above, I used a cargo strap looped over the top and attached to eye-bolts on the subfloor under the fridge.



http://www.homedepot.com/p/Ventamat...Thermostat-with-Firestat-XXFIRESTAT/206561081

http://www.homedepot.com/p/Suncourt...-Temperature-Sensitive-Switch-DS100/100028788

http://www.homedepot.com/p/Suncourt...H=REC-_-rv_search_plp_rr-_-NA-_-206584727-_-N

 

[tx2sturgis]

... the thing is you take a more typical size fridge of 1.3 - 2.7 or so cu/ft and they're $70-100. You can go through 5-6 of them to every one 12v fridge.

 {snip}

and given that it just pulled 5a over 12hrs...

Absolutely.

Its working out well for Sab...so far...

It worked well in my old Winnebago...I learned a few things back then, but I was NOT running it on solar. (back then, solar cost a LOT more than it does today!)

If you take the cost savings (compared to an RV fridge or 12v fridge) and apply them towards even one more solar panel, you still come out ahead financially, and pretty much recover from any inefficiencies of the inverter setup.

On a large RV you do have the luxury of a lot of real estate on the roof...thats a factor here.

Of course, in a normal van, things are different....roof space, and therefore solar capacity, is constrained.

I, for one, am looking forward to seeing the outcome of this 'roll yer own' alternative to $1500 RV fridges or $600 12v compressor fridges used on solar.

 

[Ballenxj]

For this project i am replacing 2 way rv fridge with a 110v fridge. It is a 4.3cf Insignia brand from Best Buy.

The rv fridge worked fine but i wanted to see if it was possible to run a solar powered apartment fridge in our camper. Also it has a freezer that is twice the size of the rv fridges. My wife really wanted more freezer space.

We had a well used dorm fridge in the basement with similar power demands. I ran the used one for several days to test things out before making the purchase.

The pics below show the space that the rv fridge occupied and the new one sitting in it's place. After all the electrical is sorted out, the finish work will be done on the install.

 Looking good so far, and I'll be following this thread with great interest. Looking forward to reading the data you post, as I am looking at doing this very same thing in my TT.
Question, did you plug the propane line? Also, did you have to splice in for your fridges 110v supply, or was there an outlet there already?

 

[Sabatical]

During the course of the day i was thinking about this project and i remembered that when we built our tiny house i installed one of those Grape Solar 5cf fridges that runs on 12v dc or 120v ac. As i recall (cloudy memory) it drew 5 amps continuosly when running. I probably could've made it more efficient by cutting the ciggy plug and a few feet of cord and wiring it direct to the 12v feed but it was new and doing so would've voided the warranty. Truth be told, we hated it. It was noisy and ran a lot. The shelves were not adjustable and you couldn't stand a carton or pitcher of liquid up in the darn thing. I don't miss that $700 fridge. Btw the tiny house was wired for 12v and solar powered.

This is the only picture i have of the grape fridge apparently. It's tucked in the right hand corner of this pic.

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[Sabatical]

I've got the numbers for today. It's still light out but the panel isn't getting enough to produce any more power today. I'm not sure how to interpret these numbers though. The whiz bang jr states that currently there 216ah in the bank. However the amount produced for the day, on another screen, reads 0.6kwh and 48ah.
I would tend to believe that the 48ah is a reliable number. The part i'm not sure about is the whiz bang jr telling me that i've stayed within a ten ah range of bank capacity.

The fridge is empty and will be that way until snowbird season when we head for AZ. It is set at 4 on the dial which has a range of 0-7. I don't have a fridge temp gauge but i'll pick one up, along with a kill-a-watt soon.

I followed the home depot links and i think that's a good way for me to go for venting. One question on the first controller though, is 1200w it's capacity for the fans draw? I wouldn't think a controller would draw much on it's own but i don't have any experience with them.

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[Sabatical]

 Looking good so far, and I'll be following this thread with great interest. Looking forward to reading the data you post, as I am looking at doing this very same thing in my TT.
Question, did you plug the propane line? Also, did you have to splice in for your fridges 110v supply, or was there an outlet there already?

I had a tee in the propane line because our wave heater is stored in an adjacent cabinet. I removed the tee and rehooked the heaters supply line.

There was a 110v receptacle in the fridge cabinet. It ties into the power center. When i installed the dedicated inverter, i took the romex out of the power center and hooked it to the inverters output. When the inverter didn't meet the fridges startup demands, i moved the romex back to the power center. The campers power center is fed, on the 110ac side, from the Bestek 1000w modified sine wave inverter by way of a piece of 10ga romex wire.

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[tx2sturgis]

I followed the home depot links and i think that's a good way for me to go for venting. One question on the first controller though, is 1200w it's capacity for the fans draw? I wouldn't think a controller would draw much on it's own but i don't have any experience with them.

All it is, is an ugly but simple and reliable thermostat, it doesn't draw any power on its own...It can handle 1200 watts of fans.

A small fan you would be using either AC or DC would be less than 10 watts I would assume. Probably more like 2 watts.

There will be two black wires coming out the side or the back and you wire it in the fan circuit just like it was a switch. Screw it to the wall inside the fridge compartment area, and apply power, test it by turning the adjustment then set it where you want it, I set mine for about 80. There is a wide 'swing', its not like a home thermostat.

Set at 80, it will probably come on at around 85 or so, and run until the temp drops to around 80 or maybe 75, so you will have to experiment a bit with the settings.

Your fan will not run very much except on hot days. Nothing in the thermostat or the fan will draw ANY power unless the temp climbs and the fan is running.

Its pretty basic.

 

[jonsun]

I've got the numbers for today. It's still light out but the panel isn't getting enough to produce any more power today. I'm not sure how to interpret these numbers though. The whiz bang jr states that currently there 216ah in the bank. However the amount produced for the day, on another screen, reads 0.6kwh and 48ah.
I would tend to believe that the 48ah is a reliable number. The part i'm not sure about is the whiz bang jr telling me that i've stayed within a ten ah range of bank capacity.

The fridge is empty and will be that way until snowbird season when we head for AZ. It is set at 4 on the dial which has a range of 0-7. I don't have a fridge temp gauge but i'll pick one up, along with a kill-a-watt soon.

I followed the home depot links and i think that's a good way for me to go for venting. One question on the first controller though, is 1200w it's capacity for the fans draw? I wouldn't think a controller would draw much on it's own but i don't have any experience with them.

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what would really concern me is why 260w of solar has only produced 48ah in a full day. I think the numbers mean basically the fridge has used 39a today. so when its warm out its using about 3 amps and hour average which translates into a duty cycle of about 25%....you're right on par with the other guys thread I mentioned earlier.

 

[Ken in Anaheim]

Am I correct that these "apt. fridge's" can ONLY be used in the vertical position ?.....................thanks

 

[tx2sturgis]

Am I correct that these "apt. fridge's" can ONLY be used in the vertical position ?.....................thanks

Yes. They are meant to be more or less vertical, standing up.

 

[tx2sturgis]

Sab, here is one of my leftover duct fans from my trailer build and the old thermostat from the motorhome I had.

Not much to them.

 

[highdesertranger]

wonder why I had such a bad experience with these dorm fridges. when I tried to use them they sucked power and had a hard time keeping everything cold. I had to turn the thermostat way down and the thing ran almost constantly. I didn't install it in a cabinet. it was in the mid 90's temp wise. as a side note I just picked up another Engel 40qt for 300 bucks. like new only used a couple of times and no inverter needed. if you look around you can find good deals on 12v refers so really don't understand why all this messing around with a dorm refer. highdesertranger

 

[tx2sturgis]

I had to turn the thermostat way down and the thing ran almost constantly.  I didn't install it in a cabinet.  it was in the mid 90's temp wise.  

{snip}

really don't understand why all this messing around with a dorm refer.

I guess the same reason people mess around with any stuff...cuz its there!

I do remember mine struggled a bit in the heat..thats why I added the fan....they just dont have much insulation, and are meant to be used in a normal living space, about 65 to 75 degrees. But as I said, on mine, it was not running on solar....and I was cheap!

As far as Sab I think his wife wants a big freezer...you are right tho, you can buy a dedicated 12v  freezer and just add it to the system with a 2-way fridge already running, but then you might have space issues....anyway....its fun to mess around with stuff...I've been doing it since I was about 6 years old...cant stop now!

By the way, here are pics of my old 1987 Itasca Class A right before I sold it:

 

[jonsun]

wonder why I had such a bad experience with these dorm fridges.  when I tried to use them they sucked power and had a hard time keeping everything cold.  I had to turn the thermostat way down and the thing ran almost constantly.  I didn't install it in a cabinet.  it was in the mid 90's temp wise.  as a side note I just picked up another Engel 40qt for 300 bucks.  like new only used a couple of times and no inverter needed.  if you look around you can find good deals on 12v refers so really don't understand why all this messing around with a dorm refer.  highdesertranger

because mine already has a TEC fridge. If I buy a chest style it's just more room being taken up I don't have and fridge sitting there not being used. I can spend $600 on a trucker fridge and have to buy $150 panel for it, or buy a $100 fridge and a $150 panel for it.

 

[Sabatical]

Nice Itasca t2s!

HDR, it's like anything else in life, we keep trying different stuff til we find what we like.
As an example...
We've had just about every kind of off grid toilet and now we are back to a sawdust bucket toilet. It works best for us.

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[Sabatical]

Bardo,
I hear ya. We would have to really make some changes to have usable room for a chest fridge and freezer. I invision having to tear apart the fridge cabinet and build shelves in it's place to hold a chest unit.

I'm not opposed to the chest units in any way. I imagine they are at least twice as efficient as the upright we installed. It wouldn't require an inverter...many benefits. My only buying options for them here in the northeast corner of new york are on the internet. That grape solar fridge i talked about before came from amazon and it took a couple trys to get one that was usable. Even the second one had some shipping damage but out of view. Not in a hurry to go through that again.

With this fridge purchased from best buy, we can get warranty service for it nationwide, provided they don't close the doors.

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