Refrigerator power consumption

[Chubby Bunny]

I'm thinking about installing a little fridge on my 22' that draws 3 Amps at 12VDC but don't know whether to upgrade my house battery.

Has anyone measured the power consumed over a 24h period to know how many amp hours it would draw at a given air temperature range?

[Captains Cat]

3 amps x24 hours = 72 Amp Hours. But it won't be running all time time. Depends on how full it is of stuff, what the ambient outdoor temp is.
No way to tell without a lot of experimentation. What size house battery do you have?

Charlie

[jlastofka]

I don't have a fridge in my C-Dory, but I have a sailboat with a fridge that's probably about the same draw as you'd buy. It averages an amp (4 amps, but 25% time) here in the San Diego area. The sailboat's constrained to the ocean, so the ambient temperature is pretty moderate. 80 degrees is a HOT day here. If you're in the desert you'll do worse of course. Or Florida, or Lake Powell, etc.

-Jeff

[Sea Wolf]

So if we take the figures suggested above (and seeing as how you live up in the Seatle/Puget Sound/PNW area) ..........

1 amp average draw X 24 hours = 24 amp hours daily

1 Group 27 battery = 100-115 amp hours, but you only want to draw it down 50% max, or even less, so you have about 50 amp hours to work with, so...

50 amp hours divided by 24 amp hours, means you'd have half that battery left for other uses.

However, I wouldn't count on that battery starting your engine after it's 40-50% drained down, but you probably have another battery (?)

You can also re-charge the battery with your engine after 6-12 hours of draw down time.

Sounds do-able to me.

What other draws do you have on the battery between engine running times?

Joe.

[journey on]

Here's my thought for the day. For what it's worth.

First, a frige is worth a lot to me. Because it keeps Judy happy and the beer cold. When we get on the boat, the frige goes on and doesn't go off until the boat is docked and we are gone. So it's the biggest power user on the boat. I've spent a lot of time trying to figure out how to supply the power to keep that sucker powered.

Second, Joe's arithmetic is impeccable. What I question is the input. Both of our last two boats have had refrigerators and the amp usage had averaged about 3 amp. In San Diego and in the Pacific Northwest. I looked at specs for Norcold and Isotherm, and they quote a number of ~2.5 for their smallest frige. Note that's an average and includes the duty cycle discussed above.

So if you crank 3 amps into Joe's figures you get 3 X 24 = 72 amp hrs. which is why I use golf cart batteries. That does not include running the engines, plugged into dockside, etc.

Boris

[BRAZO]

We have a Norcold Refridge on our 22 and love it. I can't give you solid numbers on the amp usage, but we have a 110amp hr house battery and never have any problems. We turn the refridge almost to max while on shore power and then keep it low on the hook just to make sure.

We spent 10 days on the hook in the North Channel last year and never had low battery problems.

Even though the refridge is small, we fit all we need in it without problems.

[jennykatz]

We have a Dometric tundra fridge I usually put in shore power for a 10 min or so get the fridge up and running then take off and put it on 12 volt power I find the more stuff thats in the fridge the easier it is on your battery we ahve a 115 amp hr series 27 house and a series 24 for starting

My problem is the wallas is on top of fridge and the cans inside the tundra fridge somtimes smell like diesel (cleen heat) does the fridge have a outside air coming in ??? why the smell? there are no cracks or anything broken that I can tell Does anyone else have this problem otherwise I like the fridge I usually just wash off the cans before consumption.

Also when putting on water for sink the pump seems to run even when I shut off the water ? Jim

[journey on]

Jim,

Maybe that's tundra you're smelling? Check the seal and where the coolant lines enter/exit the fridge. And look under your Wallis for drips. Sometimes they hide there.

As for the pump, you've got air in the lines somewhere. That's a good thing, since it evens out the pressure pulses, and let's you get some water without the pump pumping. Another free C-Dory feature, since they normally sell accumulators for $35 plus installation.

Boris, atop the Black Canyon of the Gunnison.