12v Refrigerator questions

[PancakeBill]

Friend has a Keysstone Cruiser Air TT, Has 2 door Everchill fridge. 12v. Runs his battery down overnight. He has some sort of solar, I saw the controller, just not sure yet if he is using properly.

Question, what do you do abut a 12v frig when boondocking?

Tomorrow, I'll go over with my meter and check some things. I am thinking, since he says he never messed with the switch by the solar, it might not be in play? Big battery switch.

 

[rvlifer]

do you know how much the fridge is pulling and how many and what kind of batteries? My residential fridge doesnt use 100ah in one night

 

[Primerump]

best practice would be to measure the power draw over a 24 hour period and use that as a starting figure to determine the battery and solar capacity required. from personal experience I know that a polar N10DC 12V fridge consumes around 700 to 1000 W/h a day in a warm climate.
that equates to an average draw of 30 to 42 Watts.
worst case could be 1000 W/h per day and to keep it running over a period of say 3 days
without sun would require 3000 W/h or 250A/h at 12V.
solar power to maintain that load and not go dark would be at least 300Watts with good sunlight
these numbers are just estimates and not to be considered final.. if you want to get serious then
we need much more detailed load numbers.

 

[DonTom]

, Has 2 door Everchill fridge. 12v.

This one? 14.5 amps? Close to 200 watts when it is running:

-Don- Q., AZ

 

[triplethreat]

Real world numbers here....I have a Norcold 2118 that has the JC Refrigeration 12V TWIN Compressor mod done to it. So a couple of factors.. It's 18.x cu ft AND there are TWO 12VDC compressors, one for the freezer section and one for the fresh food section. That unit, on average, will consume approx. 145 AH of power in a 24 hour time period...so quite the power hungry beast. I would think that a smaller unit and only ONE compressor would be quite a bit lower than the 145 AH, but the only way to tell is to know the typical power consumption and how often it runs....which of course has many, many variables.

 

[Mark_K5LXP]

Runs his battery down overnight. He has some sort of solar

Solar doesn't work at night.

what do you do abut a 12v frig when boondocking?

Same as any other load - watts in need to equal watts out. There are loads other than the fridge to be considered as well, though the fridge is probably the elephant in the room. If the solar can't keep up he's looking at more solar, or running the genset more. After that if he can't make it overnight off a fresh charge, then storage needs to be increased. To know how much of solar, genset and battery one needs requires some empirical or decently estimated consumption numbers. Second order consideration would be to adjust one's consumption through time shifting and use habits which can make quite a bit of difference, if generation and storage costs are a factor. You start with what's there and how it's used now, that sets the baseline, then hardware and operational considerations can be made.

Mark B.
Albuquerque, NM

 

[Gary RV_Wizard]

As others have said, first & foremost this is an arithmetic problem. Measure, or at least make an educated estimate of, the power (watt-hours) consumed by the fridge and other 12v loads each day. Then do the same for the power available to service that need, i.e. what is stored in the battery(s) and what can be added by the solar on a typical day. Once the numbers are known, it's a choice of using less or providing more. Usually some of each.

More/larger batteries (more watt-hours in storage) lets you bring more power initially and store more for overnight use when the solar isn't producing. More solar can increase the power fed back into the batteries so you can repeat day by day. Don't think of solar as the operating power source - think of it as power replacement, refilling the battery which acts as the fuel tank.

The power consumption label on the fridge is only a piece of the data needed. You also need the fridge "duty cycle", i.e. the number of hours per day the cooler (compressor) runs. That's hard to guestimate because it varies by time of day, temperature, frequency of door openings, etc. That's why measurement is much better than estimating.

A hint: 12vdc power available or consumed is calculated in watt-hours or amp-hours. Those are easily converted to each other. DC watts are amps x volts and the volts in an RV system are nominally 12, so 1 AH @ 12v = 12 Watt-Hours

 

[PancakeBill]

Solar at night,, you don’t saay...

Need to find the data sticker, just looked quick yesterday, will look closer. I have a clamp meter so I can at least see what kind of draw. I am thinking he doesn’t understand the solar etup he has, the walkthru guy did a bad job. I have access to it this morning. My main consideration right now is getting his bad tankless removed.

 

[Hfx_Cdn]

I realize the string is responding to the OP's original request, but the simple solution if it is a 3 way fridge is to run it on Propane which uses limited propane. I only used 12 to run the fridge when we were travelling through a tunnel that required the propane to be shut down.

Ed

 

[CharlesinGA]

The Everchill is a 12v DC COMPRESSOR fridge. No propane, no 120v AC

 

[PancakeBill]

Rated current on the frig is 14.5 amps! No wonder. so 174 AH

 

[DonTom]

Rated current on the frig is 14.5 amps! No wonder. so 174 AH

If the compressor runs for a full hour, that will be 14.5 AH.

But I think you meant 174 watts (12v times 14.5 amps=174 watts). But the compressor will not be on full time so it will be less than 14.5 amps per hour.

-Don- Q., AZ

 

[PancakeBill]

Don, yup you got me on that one.

 

[No cats]

If the compressor runs for a full hour, that will be 14.5 AH.

But I think you meant 174 watts (12v times 14.5 amps=174 watts). But the compressor will not be on full time so it will be less than 14.5 amps per hour.

-Don- Q., AZ

I looked at it a different way. I thought he meant that if the refrigerator draws 14.5A when running and it runs for 24 hours at a 50% duty, then the result is 174A.

14.5A x 24h x 0.5 = 174A consumed

 

[Kirk]

Rated current on the frig is 14.5 amps!

My son has a fair sized Everchill and loves it. His does have a separate door for the freezer and the chill box but I'm thinking that you mean a double door to the chill box. Did you ever take the measurements that you were going to?

 

[DonTom]

My son has a fair sized Everchill and loves it.

I can see the advantages for me of a compressor refrigerator, such as being able to turn in on in advance to let it cool down at my Auburn house where it is nothing near level. And also, when it is too hot, to prevent this problem.

But otherwise, the four-door Norcold in this Class A, a Norcold 1210T (wood trim) is perfect, keeps perfect temps and very roomy, and not a large load on batteries (1.8 amps, 22 watts @12.2 VDC when on propane).

456 watts , 120 VAC @ 3.8 amps when on shore power.

 

[PancakeBill]

My son has a fair sized Everchill and loves it. His does have a separate door for the freezer and the chill box but I'm thinking that you mean a double door to the chill box. Did you ever take the measurements that you were going to?

Not yet. Next week. Double as freezer and other door

 

[PancakeBill]

I looked at it a different way. I thought he meant that if the refrigerator draws 14.5A when running and it runs for 24 hours at a 50% duty, then the result is 174A.

14.5A x 24h x 0.5 = 174A consumed

Exactly

 

[DonTom]

4.5A x 24h x 0.5 = 174A consumed

I assume you meant 174 AH consumed.

But your above math comes out to 54, not 174, so I am not sure what you meant there.

-Don- Picacho Peak, AZ

 

[No cats]

@DonTom, I don't know how you pasted my quote wrong.

This is what I wrote;

I looked at it a different way. I thought he meant that if the refrigerator draws 14.5A when running and it runs for 24 hours at a 50% duty, then the result is 174A.

14.5A x 24h x 0.5 = 174A consumed

Your quote changed my 14.5A to 4.5A. Good try, but no dice

Yes, I meant 174Ah. Up until today, I didn't have the privilege to edit my posts. However, editing privileges for that particular post have lapsed per forum rules.