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HowTo How much solar do you need to run a house fridge: RAIN or SHINE

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Id like to explore power options when the power goes out. Where going to see how many solar panels I need to run my house refrigerator. First we’re going to see how many solar panels I need to run the fridge during sunny conditions, and then we’re going to do another test to see how many solar panels I need to run my house refrigerator in cloudy conditions. The goal here is to indefinitely always have a cold place to store my food without having to worry about a generator or having gas on hand. But let’s get started. So recently I posted a couple videos on running my house fridge first with a large 48 volt battery and power system that I currently have in my RV build. I also ran the same test using this smaller battery and power system. I was able to run my house fridge for 17 hours using this battery. But I had a lot of comments asking me how long could I run it if I had solar panels attached. So that’s what we’re going to do today with this specific system. Let me show you a little bit about the different about the equipment we’re going to be using. This is a lithium iron phosphate battery from Power Queen.

Feel free to shop around for these batteries. I like this one. This is the 100 amp hour mini version. This one’s just over $300. But you can get one that’s just a little bit bigger and that’ll save you like $75 or something. And that will be under $300. That’s a great deal because you can discharge this battery to zero every single day for something like 10 years. But they’re pretty new and they last a really long time. They could last even longer than that. I’m going to be using this Victron Pure sine wave inverter. I’m just going to connect the positive and negative terminals and then I will have 120 volts AC to power my fridge. And this right here on the top, this is a battery monitor. So I just connected this to the to the terminals as well. So all the power flows through this. I can measure how much power is coming out of the battery. But feel free to shop around for the battery.

If you want to buy this battery, I do have a discount code. I’ll leave in the description. If you like any products that I show in these videos and you want to support the channel, feel free to use those affiliate links I have in the description. People usually don’t use them, but it really helps the channel out a lot. See how much solar panels we’re going to need for the sunny tests. Now this is a small battery and a small inverter. My fridge would turn on and off throughout the day.

But with this soup with this efficient system, this was using 75 watts on average of battery power to run my house fridge. The larger, bigger system for like a cabin, it was using 100, about 100 watts of battery power just because it was a bigger system and it was had a bigger inverter and it was more designed to handle larger loads. This is a small, really efficient inverter. So we’ll take that into account. So if I use 75 watts to run my fridge, and I need to run that for 24 hours, I’m going to need 1800 watt hours of battery power to keep my fridge running every single day. So that’s how many watt hours I’m going to need to get from the sun. So I’m going to be 1800 watt hours is the goal to collect every single day.

So I think in Utah in August, I think I’m going to have full sun about 10 o’clock till five o’clock. I’m just guessing. So that is seven hours of sunlight. So if I divide 1800 watt hours divided by seven hours, that is 257 watts of solar. I’m going to need out during that seven hours. The solar panels I’m going to be using, they are 240 watts. But solar panels, hard level produce 100% of their energy, their stated energy. Usually a good number is like 70%. So I’m just going to say 240 times 0.7. So realistically, each panel is going to give me 168 watts of power. So that’s not quite 257. So I’m going to hook two of these panels together. And that will give me 336 watts of realistic power from the solar panels. So that should account, give me a little bit of buffer room. So if some clouds come over for part of that seven hours, I should be good there. So let’s do it. These are $50 use solar panels. I got from Santan Solar. I do have a discount code for these as well.

It’s a great deal. Shipping is kind of expensive. But if you live near Phoenix or Georgia, you can go into their office and pick them up for free. A lot of people buy these and resell them on local classifieds ads to make a little bit of money. I’m going to maybe try that in another future video where I can see if it actually works. I’ll include a link to a web page they have where they have free shipping on certain panels. You’re not buying any of the solar panels. Let them know I sent you either when you call or in the comment referral box they have. That’ll help me make more videos like this. It looks like they’re Georgia storage shutting down. So they’re clearing out all their solar panels out of the Georgia location. So if you live near Georgia, it could be a good time to go pick up a bunch of panels. Okay, here’s the solar charge controller we’re going to be using.

First I’m going to connect the battery, positive and negative to the battery. And then I’m going to connect the solar to these two MC4 connectors. I’ll put links to these in the description. This is a Victron. This model can accept 100 volts open circuit from my solar panels and it can’t output into the battery more than 30 amps. So 30 amps times 12 like 340 ish watts. Never get more than 340 watts out of this unit. This one’s kind of expensive but I’m going to do another review with a bunch with other types of charge controllers. Well check that guy out. See you later buddy. Okay here’s my two solar panels. I’m going to connect together. I’ve gotten covered. I don’t get shocked but this one’s going down so there’s not any sun out here. Anyways, so each one of these solar panels is 37 volts open circuit. So when I hook them up in series we’re just going to hook the positive from one panel to the negative of the other.

Because they’re hooked up in series the volts doubles. So it should be just under 80 volts coming out of here. Okay to hook this battery monitor up you just connect this to the negative and then this acts as the negative to the battery. So use this as the negative to the battery and then all the power will flow through this battery monitor shunt. Use that for the positive and this as the negative terminal. I’m just going to connect this right now. Okay that’s connected and the sun is just going down there. Got this extension cord running to the fridge. Okay that’s good. Fridge is on. Looks like the battery is right at 99 percent. We’ll see what the state of charge is in the morning. Nice thing about this 100 amp hour battery is it’s perfect for a fridge because there’s just enough power to run my fridge throughout the night and a little bit into the morning.

So it should never fully run out of power at night time. And then when the sun comes out in the morning theoretically it should charge it up and top it off for another night. So tomorrow if it gets fully charged we’ll call that a success for the sunny conditions. The forecast is showing sunny tomorrow but I’ve had enough solar panels. Hopefully I can handle a little bit of clouds. We’ll check back tomorrow. Oh this is going to be an amazing sunset. Shish. Okay so it’s 10 o’clock the next day. It’s pretty sunny out here. Food has been cold in the fridge all night long. One thing I didn’t account for is fire season and there is a lot of smoke in the air right now. First let’s check the battery. Okay the battery is at 16 percent. Let’s look at how much solar we have coming in. So I just realized I don’t have my solar connected. Let’s plug this. I’ll just plug this in and let’s have a look. 240 watts so that’s operating at 50 percent of its capacity. It is really smoky out there so I hope we get a little more power than this. It looks like the battery is accepting a charge now so we’re in the positive so this should start going up. Maybe it could have been charging for another hour. Okay I’ll just let this graph run. Okay it’s four o’clock. It looks like the air cleaned up real nicely.

So it is showing pretty much fully charged. It’s been charged for a while now. That many solar panels will definitely charge the top of the battery off. It’d probably be better if I had a 200 amp hour battery. That’d be more ideal. That’d be even better because then yeah this extra power from the solar is being wasted right now. So a 200 amp hour battery might be nice because then I could if I really had power out I could run my laptop and my wi-fi router and my TV. So yeah I’m just going to let this run all night. We’ll see what that we’ll see in the evening what time of day the percentage starts going the charge percentage starts dropping going down. Okay we’ve had some clouds and a bunch of big trees over there blocking the sun. So the battery is starting to go down a little bit. Let’s see if this lasts in the morning. We’ll check back in the morning see how it is. Okay guys good morning it’s 8 30. Let’s see how much charge we have. 8 40 actually. 31% on the battery.

So the sun should come up shortly and we know that the sun can charge this battery. Okay guys it’s time to test how much solar we need when there is cloudy conditions. Now to get me through a storm I could buy an extra battery for $250 but that’ll only get me an additional 17 hours of power for my fridge. After that I’d be done. But if I take that same $250 I’d spend on the battery and put it towards a bunch of used solar panels that are super cheap. I could I should be able in theory I should be able to get through the storm and just have indefinite power rain or shine for cold food. Now I’ve waited most of the summer to get this type of storm so it’s just about to rain on me here.

Looking at the forecast we got five days of pretty good storms here. Hopefully while cloud covered the whole time we might have some sun seeping through but it’s a good realistic longer storm. But let’s try and estimate how much solar we’re going to need in this scenario. So doing a quick search on the internet to see how much solar panels produce during cloudy and rainy conditions. Here’s a website that shows 10 to 25 percent so we’ll go ahead and test this out.

So because I’m testing cloudy conditions and partial sun conditions I’m going to guess I have partial sun in this area from 8 a.m to 8 p.m on partial sun conditions. I have a larger window there and I’ve got six of these 240 watt solar panels totaling a total of 1440 watts so assuming they only produce 10 percent of their of their state output that’s 144 watts. So 144 watts times 12 hours that’ll get me 1728 watt hours. So in order to run my fridge for a whole day I need 1800 watt hours so that’s going to be pretty darn close. So during the day in these cloud conditions I might be able to get enough power to top my battery off. I’ll show you how I wire this up. So I’m not going to get more than 440 watts out of this charge controller if it when it can only output 30 amps. So that’s something to consider. So we’re going to put more panels out than we need so we still get sufficient power when we have clouded conditions out. So let’s go look at the wiring. Let’s go wire up the solar panels. So first step I’m going to wire these three solar panels in parallel. I’m going to be using these little splitters in order to wire all of the negative sides together and here I’ll use this one to wire all of the positives together. I was going to use this attachment but the solar panel wires weren’t quite long enough to reach the two ends. Okay so these three panels are now wired in parallel so I have one positive and one negative and we’re going to do the same thing with the other three panels. Okay so I’m done with that.

So I’ll connect the negative on this side. There we go. Two. The positive on this side. So now I just have one large positive and this side just one big negative. So that is a 3P2S configuration. So because we’re wiring these three panels in parallel that means we add the amps together. So that’ll be about 24 amps of short circuit current and 24 amps of short circuit current for these three. Because we’re wiring both those groups of three together in series we add the volts together so that should be just under 80 volts for this whole array. Just want to make sure we’re under the 100 here so that’s good. It looks like looking at the documentation this specific model of charge controller can accept up to 35 amps of current so we should be good there.

All right let’s see how much power we got coming in. 57 58 watts coming in right now. 94 percent. So it is pretty dark skies out here. I think it’s 445 right now so I think the sun’s somewhere over here. So the panels aren’t getting too much energy right now. Let’s go ahead and plug in the fridge. Yay okay we’ll check this in the morning at eight o’clock. It’s got to go like 15 hours from now I believe that so that is. I bought these blocks from Home Depot so I could use them in the summertime if I need to use this array and allow the tilts to be greater and allow air to flow underneath them. Most of the wind here comes from the north and so these are pretty protected. I haven’t had any problems with wind. This wire here is 10 gauge wire same wire I would use for my 30 amp RV plugs but I shouldn’t have more than 24 amps going through that. Okay eight o’clock. The fridge is still running. We went down to 16 percent last night. Current weather conditions.

So it’s just coming out over there. Blue is a state of charge you can see throughout the night when the compressor kicked on and off throughout the night. Now if you notice that larger dip in power draw I think that was my defrost cycle kicking on melting the frost from my refrigerator coils. Now other people have mentioned in the comments to disable that to save power but if you’ve got frozen coils in your refrigerator or freezer probably not a good thing. I’m going to keep that enabled. Okay it’s been raining all morning. Our solar panels got cleaned off a little bit because of the rain.

I would define it as light cloudy conditions. I don’t have a I don’t really have a shadow but bright clouds. Let’s see how much power we have coming in. So I forgot this smart Victron solar charge controller has Bluetooth app so I can look all look at all the solar data from the app. Currently 250 watts coming in so I have 18 amps going into the battery. Just maybe 15 minutes ago I did have 30 amps coming into the battery so it was operating at 100 capacity and it was still shady but it must have had a little dark darker cloud come over. Okay so this is kind of cool if we look at the history you can see how much power I’m getting from the day. So it looks like I’m almost at a thousand watt hours. So I need 1800 watt hours ideally to continually run my fridge so it looks like I’m going to be on track for that. Battery’s at 57% it looks like I was at a low of what 17% and the battery state of charge is climbing. So it is Tuesday at noon I’m actually heading out of town for the rest of the day on Tuesday. I’ll be gone all day Wednesday and half of the day on Thursday. So I’m just going to leave it plugged in. We’ll come back and see how much data we are getting. That solar charge controller kind of nice so when this when it’s raining really hard super dark clouds you don’t have a lot of power coming in but if the sun ever peaks out it gives it gives that battery a real big boost. I think I could get a different charge controller that will give it even a bigger boost if the sun pops out. That battery can charge at 100 amps but it’s recommended between 20 and 50 amps. This is a 30 amp charge controller so that’s a good medium. We’ll check back then a couple days. Okay here’s our charge controller usually it’s bulk charging once it gets full it goes to absorption and float so it’s showing the battery is fully topped off now. Okay the two days ago that was Tuesday looks like that was the first full day and we got two kilowatt hours of energy into the battery.

I believe that’s because the Monday before the battery was pretty much fully depleted so the battery was able to accept more energy. So yesterday morning I assumed when the sun came out the battery must have been fairly charged because it only accepted 1.7 kilowatt hours of energy. Now today I’ve only had 1.4 kilowatt hours of energy going to the battery and it’s fully charged. Now throughout the day as the fridge continues to run it’ll go up a little bit more but it’s looking pretty good. It is raining. Let’s see how much power we’re getting during the rain. Come on here we go. The phone’s getting soaked here. 63 watts. 63 watts during the rain. Not a lot of power when it’s raining. So the rain cloudy test kind of a boring test it just kept running. It’s actually still running out there on the battery right now. That last rainstorm I had I thought it was going to not run throughout the night because it was rainy all day and at three o’clock I left out of town.

I needed like 60% battery power for it to last through the night and it was like at 30% at three o’clock but then three o’clock the rain stopped and like it charged the battery right up to like 100% so about six solar panels I think it’s perfect. The 100 amp hour battery is pretty good. I really like the size lightweight you can carry it around. That’s a mini version I was using which is 19 pounds. You want the regular size version it’s like 25 pounds but the regular size it’s like 270 dollars. The mini size is 309 dollars. You want to jump up to a 200 amp hour battery that’s a little bit bigger it’s 43 pounds so it’s a lot heavier to carry around a lot less mobile. Those are like 579 dollars for a 200 amp hour version. There is a company that makes a 140 amp hour 12-volt battery which would be pretty good as well. That only weighs 28 pounds so I think that would probably be the best battery for a mobile fridge unit that you want to run in the winter time during long nights.

I think my fridge is pretty typical but you can use one of these amp kilowatt meters to measure how much power your fridge uses. My fridge uses 63 AC watts of power on average and 75 DC watts of power. There’s a little bit of if it has to run the inverter to switch it over to AC power that’s why that’s why it uses 75 watts of DC power. Now if I plug this in all year let’s see how much money I’d be saving. If it’s using 65 watts of power times 24 hours times 365 days times about 15 dollars per kilowatt hour it’s going to cost me 85 dollars a year to run my fridge my house fridge. Now if you want to pick up six solar panels six used solar panels one of these batteries and an inverter and solar charge controller the inverter and solar charge controller are victron’s so if you go with a non-victron brand you can definitely save a little more money. If you pick up all that stuff for $850 you’ll be getting a 10 return on your money so that’s not too bad. I’ll put some amazon links in the description for the full kit so I was just looking at Honda generators you can get a thousand watt Honda generator it’s going to cost you a thousand dollars and you have to make sure the carburetor is clean you have to make sure you have a clean gas on hand if you starting an air conditioner or something generators don’t handle inrush very well you have to fill it up every eight hours so I’m pretty sure this system will run non-stop all year long for this is under a thousand dollars seems like a no-brainer to me. Someone commented in one of my last videos that they exclusively use these little power banks as backup power for their house so instead of buying a really big system where something could fail and then you have no power he has a bunch of these little tiny systems that these little mini power banks for like each of one of his fridges and then if one goes bad he still has one that works.

If you’re interested in more of a larger battery and a larger power system that can automatically switch over to grid power if the battery goes dead you can use solar during the day battery at night switch over to grid power look at this link right here I’ll leave a link here at the end of this video so look at this link and if you’re interested in how you can save money buying use solar panels I have another video on how you can get some free how you get free shipping and even make a little bit of money I’ll leave a link to this video but let me know what you think see you guys.
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