House Battery Life

[hbjoe3]

Happy New Year!

With fully charged house batteries how long can I expect them to last with just the refrigerator running?

Thanks,
Joe

[captnrick3]

24 hrs. tops. We dry camp a lot (out in open desert right now). I installed 500 watt total solar panels that provide all we need during the day. Auto Gen Start is set to start at 12.0 volts and run for two hours. Usually starts every mornimg, we usually run it manually during dinner to run the micro/oven. So far the residential fridge has not been the train wreck I feared.

[emm-dee]

24 hours????? I've left my refrigerator on (via propane) for over two weeks. Battery still had plenty of power to run the power tongue jack (a heavy power user).

What type of refrigerator power is there that would drain a battery in 24 hours.

[Kenny kustom]

Residential..?


2016 Sabre 36QBOK
2015 Ram 3500 CUMMINS

[Bluepill]

My Samsung 25 Cu.Ft French Door refrigerator uses an average of 2KWH per day measured on the 120 volt side. This is with inside temperatures averaging 72 degrees. It will use more as the temperature goes up. That equates to 180 Amp. Hr. of battery use every 24 hours. (180 x 12 volts x 92% efficiency for the inverter). Since you do not want to discharge your batteries more than 50%, it requires 360 Amp. Hr. battery capacity just for the fridge. The size of your battery bank and the exact usage of your particular fridge will determine your usable run-time.

[captnrick3]

Originally Posted by emm-dee

24 hours????? I've left my refrigerator on (via propane) for over two weeks. Battery still had plenty of power to run the power tongue jack (a heavy power user).

What type of refrigerator power is there that would drain a battery in 24 hours.

Residential fridge I a whole different ballgame from propane. Last 4 rigs were propane. I would rather have that if I had my way.

[captnrick3]

Originally Posted by hbjoe3

Happy New Year!

With fully charged house batteries how long can I expect them to last with just the refrigerator running?

Thanks,
Joe

Looks like your rig is exactly like ours so I answer based on actual experience.

[aeroshots]

Same here, 24 hours give or take. Some obvious but stated factors --how often you open the doors and how it is loaded. Nearly full and it will last the longest. I put those gell ice packs in the freezer making it a cooler so to speak and that helps.

[srappleby]

We are going to an air show next month and will be our first experience with dry camping. We have been practicing water conservation (not very well) but I'm worried about battery life overnight during quiet time with no generator. Sounds like I can expect my inverter and batteries to get through the 8 hours or so just fine. Any tips or suggestions?

-Steve

[CC75]

Cool down the RV residential fridge the night before you leave, with all controls on max. Pre-freeze water bottles in your sticks and stones house (bottles take at least 24 hours to freeze), and place them in the freezer of camper. Try to fill the freezer with pre-frozen bottles around your food. The ice will stabilize the temperature in the freezer as you open and close the door, thereby limiting the number of times the compressor has to cycle on. Place many frozen bottles in the fridge as well. Since the bottles will be as hard as rock, arrange them in a manner that will not destroy your fridge during travel thru bumpy roads. I place them on a dish towel in the very bottom drawer of the fridge. When ice melts in the water bottles in the fridge drink them and move frozen bottles from freezer down to fridge.
Move the temperature controls to recommended on the morning of your trip.
The start and subsequent running of the compressor is where most of the power is used. If you minimize the cycle time of compressor you will minimize the draw on your batteries. My whirlpool fridge uses less than 1 amp for the fridge's fan when the compressor is not running. Of course the compressor reference only applies to residential fridges. The frozen bottle use to manage temperature applies to both types.

[aeroshots]

Outstanding advance by cc75. I use my stash of jell filled freezer packets in place of water bottles. Wife and I get a weekly delivery from "home chef" which contains 5 or more freezer/cool packs. I have the RV freezer almost full of them while in its storage barn and distribute them prior to travel.

[ScottBrownstein]

I agree with CC75 with one exception. Don't touch the setting on the reefer. It won't get to 0 in the freezer and 40 in the reefer any faster that way! Modern units will first try to get the freezer to the control setting before sending cool air into the reefer. Setting it lower will only prolong the amount of time that the reefer section doesn't get cooled all that well. The compressor runs when the temperature settings have not been reached. It doesn't matter how different the desired temperature is from the current temperature.

[Bluepill]

The frozen water bottles in the freezer are a good basic idea, but ice has a very limited capacity to "Absorb" heat as it warms up. Much more heat (a factor of 80) is absorbed during phase change when the ice melts. Of course, that does not happen until the temp rises to 32 degrees, and that is really no help in a freezer.

I use a mixture of water and RV anti-freeze in my bottles. 60% water and 40% anti-freeze works well, and starts to melt at about 10 above zero, so everything stays safely below 32 degrees.

[CC75]

Frozen water bottles are a suggestion because of convenience. When we go on long trips, we take the used see thru plastic mixed nuts containers we purchased at Costco, and fill them about 3/4 way full with water and dissolve salt in them. The extra room is to account for the expansion when water freezes. It takes a good 2 days to freeze in home freezer. This is the poor man's antifreeze, and is one solid rock that stores considerable coldness, and is disposable. Be careful not to pour it over plants. The salt water may kill some plants.

[srappleby]

Thanks for all the suggestions, good stuff.

Steve