How Much Solar is Needed, Residential Fridge

[Tbos]

I’m considering adding solar to keep my batteries charged while they run the inverter for my residential fridge? This would be while boondocking but not running the generator.

[chuckster57]

How many and what type of battery(s) do you have? Are you trying to charge them during the day to make it through the night? Are you looking to run the fridge AND some 12V stuff during the day?

How much solar is going to depend on how much your going to use and how much reserve you have.

[Tbos]

20450 here’s a picture of my Batteries. I have 2 the same in parallel. In addition to the inverter running the full size Samsung Fridge is the standard 12v monitors that are always connected. Use would most likely be to just keep the batteries charged enough to run the inverter, fridge and detectors.

[JRTJH]

Tom,

You're going to need to do some "advanced math" to determine how much power your system will use. Keep in mind that the refrigerator will run longer and more frequently at 90F than it will at 70F, so taking "worst case scenario" into your considerations will get you a more accurate "guess" at what size battery/solar panel array you'll need. Also, realizing that a cloudy day will not provide as much power as a sunny day, parking under trees, and I'd suspect a long list of other "don't forget to take this into account" things will probably show up in your calculations.

Getting a "general idea of what you'll need" is a good thing, but when you start looking at an investment in the "thousands of dollars" range, getting "as close as possible" to the actual requirements really gets important.

I don't have any idea what size system you'll need, but I do know that the size will be significantly larger (in watts produced/needed) for a system in south Louisiana or Texas than one in Oregon or northern Michigan. I wouldn't know where to begin to calculate the actual wattage requirement for an "across the board requirement that would be sufficient in all temperatures and in all climate conditions".....

[Fishsizzle]

Yes, there are a huge amount of variables.

Head over to the upgrade forum. There is a member there adding batteries and solar as we speak. There are other threads there.

Best advise, strike up a conversation with some offgrid or tiny house people. Lots of them have experience with solar and can help you to start calculating you usage, then build a system around that.

I’m going to head down that road as well, one day!

[Canonman]

The big draw is going to be the fridge. The rest of the stuff, TV, accessories etc. can easily run on your two batteries through the night and be recharged by a 100 to 200 watt solar unit during the day. If you know the amp draw or watts for the fridge and calculate the average run time, you can figure how many additional batteries you'll need and the sizing for the solar panels to get you through "X" days. It is considered normal to think of solar as simply extending the run time on your batteries.

[Tbos]

Thanks for the advice. A friend is spending over $6K to put solar (including lithium batteries) in his. I’ll have to talk with him about the calculations his vendor is using. I’m pretty sure he plans to use his solar for more than just running the fridge. I did consider the availability of the sun and the the temperatures in the rig too. I’m not comfortable leaving a portable generator running while I’m not there. I’m also currently not comfortable with spending $6k for solar.

[Tbos]

The big draw is going to be the fridge. The rest of the stuff, TV, accessories etc. can easily run on your two batteries through the night and be recharged by a 100 to 200 watt solar unit during the day. If you know the amp draw or watts for the fridge and calculate the average run time, you can figure how many additional batteries you'll need and the sizing for the solar panels to get you through "X" days. It is considered normal to think of solar as simply extending the run time on your batteries.


Thanks, more good information.

[Fishsizzle]

Thanks for the advice. A friend is spending over $6K to put solar (including lithium batteries) in his. I’ll have to talk with him about the calculations his vendor is using. I’m pretty sure he plans to use his solar for more than just running the fridge. I did consider the availability of the sun and the the temperatures in the rig too. I’m not comfortable leaving a portable generator running while I’m not there. I’m also currently not comfortable with spending $6k for solar.

The lithium batteries are the biggest expense. They are outrageous.

You could design a system with sealed/Gel and I bet you’d be half that cost.. But the beauty of Lithium is the ability to draw them further down (lead can only go down to around 50%) and they triple the cycles. So it’s an equalizing but hard to bite that much off in the beginning.

Check out the app “alibaba Express” in the App Store. Batteries are straight from the source, China. About 1/2 the price that they sell here in the states. Same components, most of all lithium comes from China

[bsmith0404]

A typical refrigerator will draw about 20-25 amp hours. inverters are not perfect so expect there will be some additional loss/usage. With that in mind, let’s assume approximately 30 amp hours. A 150 watt solar panel will produce about 8 amps per hour. So to keep up, you would need about 600 watts of solar. True the solar will not produce electricity over night, but refrigerators also do not run continuously. Realistically, a refrigerator will probably use about 150-200 amp hours per day. If your solar system produces 30 amps per hour for 10 hours, it should keep up...in theory.

[roadglide]

Pure sine inverter is recommended and 2 K inverter would be a good starting point . I wired in 2 breakers kitchen and bedroom I was unaware the frig was in the same circuit as all the kitchen plugs that was a big bonus. I was glad I went with 3 k inverter with remote switch . I use propain for the frig but have inverter power in case I get into a bind with on gas .

[whcarr]

If your fridge was drawing 8 amp you would need about 960 Watts of power to run it, temperature is a huge factor in calculating watt draw. Your location is also important, how many hours if Sun light. Lithium battery are great. But also dangerous. I have had good luck using golf cart batteries. You will be adding lots of weight and mantenice. Check out some solar eq. Sales web site. I have had good luck with new England solar. I ended up using a gas refrigerator, it is convenient. Take your time researching.

[bsmith0404]

Not sure what RV the OP has, but new RVs with residential fridge typically come with a dedicated line with one battery and a 1000 watt inverter just for the fridge. According to specs on solar panels, a typical 140-150 watt panel produces about 8 amps.

[Tbos]

Not sure what RV the OP has, but new RVs with residential fridge typically come with a dedicated line with one battery and a 1000 watt inverter just for the fridge. According to specs on solar panels, a typical 140-150 watt panel produces about 8 amps.


I am the OP. I have an Alpine 3651RL with the big Samsung residential fridge. It currently has a WFCO 1000W pure sine wave inverter. I also have 2 series 27 deep cycle batteries. As it is currently set up the fridge will run on the batteries for quite a while. I have not done a test to see exactly how long. Of course right now it’s cold out so the fridge doesn’t have to work hard.

[Canonman]

In researching what I might need to enhance my camping options with solar, I ran across this site: https://www.rvwithtito.com/articles/solar-for-your-rv
The information was real-world, thoughtful and concise. It definitely helped me with my decision.

[Tbos]

In researching what I might need to enhance my camping options with solar, I ran across this site: https://www.rvwithtito.com/articles/solar-for-your-rv

The information was real-world, thoughtful and concise. It definitely helped me with my decision.


More great information. This is very helpful.