Refrigerator on battery

[Russellvh]

I’m sure there are endless variables but maybe just a general question. I just bought a 2022 Wildcat 5th wheel. Getting ready for first “shakedown” trip. If I go to the storage place the night before and turn on my refrigerator should it be able to run all night, to cool down, with out killing the batteries???

 

[Joe Hogan]

What Size Battery To Run Fridge? Best Battery To Run A Fridge

What Size Battery Will Run A Refrigerator? Fridges are a special case among domestic appliances, in a group together with air conditioners, freezers and heat pu

diysolarshack.com

 

[Russellvh]

Electricity only. Top freezer and a little smaller than a residential.

 

[Bob K4TAX]

I’m sure there are endless variables but maybe just a general question. I just bought a 2022 Wildcat 5th wheel. Getting ready for first “shakedown” trip. If I go to the storage place the night before and turn on my refrigerator should it be able to run all night, to cool down, with out killing the batteries???

Depends on the total battery capacity in Ah and the % of charge. I'd say 12 to 18 hrs with the refrig on battery would discharge the batteries. I wouldn't bet on it cooling and keeping it cool. You really need to have the trailer on shore power to be safe.

 

[SaltyVetAdventures]

The fridge will tell you how much power it uses somewhere on a data plate. Use watts law and you can get pretty close on your calculations.

If the fridge uses 4 amps and it runs on regular 110 volt electricity. Watts law says it will use 440 watts. (amps x volts = watts). A fridge usually has a 50% to 60% run time...meaning it doesn't run all the time, only when it is cooling. BUT you are cooling down a warm fridge overnight? Figure a 100% runtime for that night to be safe.

What kind of batteries do you have and how many? Lithium or regular lead acid "car" batteries? Regular "car" batteries can only be drained to 50% capacity without damaging them. So if you have a 100 amp hour battery then you really only have 50 usable amp hours. Again watts law says 50 amps x 12 volts give you 600 watt hours. That means you could run a 600 watt appliance for one hour.

If your fridge is using 400 watts and it's running continuously, it will begin damaging your "car" battery in about 1.5 hours and completely kill it in less than 3. That is assuming the fridge is cooling 100% of the time. If you have two 100 amp hour batteries then you can double the time before your batteries die.

Of course all the numbers I used are made up. Replace my numbers with your own. This is an important lesson to learn in RVing. What can you run off your batteries and for how long. Good luck.

 

[SaltyVetAdventures]

Depends on the total battery capacity in Ah and the % of charge. I'd say 12 to 18 hrs with the refrig on battery would discharge the batteries. I wouldn't bet on it cooling and keeping it cool. You really need to have the trailer on shore power to be safe.

I am curious as to how you came up with 12-18 hours? Without knowing how many amps the fridge is using it would be hard to give an accurate number. But I am sure the fridge will be using around 4-5 amps. Since they are cooling it down from room temp the compressor will be running 100% of the time for at least 4-5 hours. 4 amps on 110 volts is 440 watts (460 watts if the voltage is 115v). Assuming the new trailer came with the crappy batteries most trailers come with, each battery is 75-100 amp hours. Lets be generous and say they have 200 amp hours and the batteries are fully charged. You can only use half of the amp hours in a lead acid battery without damaging them. So, they have 100 amp hours usable. That is about 1200 watt hours.

If that fridge compressor is running full bore trying to cool it down and using 440 watts... The batteries would be sustaining damage at about 2.7 hours. The batteries would be completely dead in under 5 hours.

Now, we would have to know the actual numbers from the fridge and the batteries. Not to mention the inverter has some parasitic draw as well.

I could be completely wrong. Maybe the start up amps on the compressor is 4 amps and the running amps is only 1-2 amps. That still would be cutting it close on cooling down a warm fridge.

 

[Cruiser Bob]

I’m sure there are endless variables but maybe just a general question. I just bought a 2022 Wildcat 5th wheel. Getting ready for first “shakedown” trip. If I go to the storage place the night before and turn on my refrigerator should it be able to run all night, to cool down, with out killing the batteries???

 

[Cruiser Bob]

It probably won't kill the batteries, but it will definitely drain them down. Gas is better and more efficient and uses little propane.

 

[Msdpok]

I’m sure there are endless variables but maybe just a general question. I just bought a 2022 Wildcat 5th wheel. Getting ready for first “shakedown” trip. If I go to the storage place the night before and turn on my refrigerator should it be able to run all night, to cool down, with out killing the batteries???

The only issue is exactly what just happened to me, we went into storage under extenuating circumstances last fall! We never got back to remove batteries… We picked up RV and turned on shut off had plenty of juice for lights, on the way home I turned on fridge, it started fine green light all the way home, once we got home we figured it was good to go but about an hour or so later we noticed the fridge shut off. Turned out the batteries were drained and there wasn’t enough juice for the fridge to run! Even though it’s propane you still need to power it!

 

[Bob K4TAX]

Saying one "drained the battery" depends on just how far it was drained. If it is allowed to go below 12 volts many times, one will need a new battery, regardless of how new or old it may be. Repeated discharge below 11.9 volts will shorten battery life. Anytime voltage, open terminal, and no-load, is less than 11.6 V this is the area of permanent damage.