I' m trying to power a chest freezer as a fridge for next summer. I would like cold drinks and using a cooler didn't work very well, this year. I have a 3.5 cubic foot freezer with a 200 kwh energy star rating. I ordered a Johnson control and already own a 1000 watt pure sine inverter. So I'm trying to figure how much solar panel and battery to buy. Will a 100 watt panel work with one deep cycle battery? I would say 5 or 6 hours of sun per day and I can always charge with a generator if I need to. Trying to do this cheap so I can put my money into building a shed and digging a pond. Can always upgrade down the road when I move to my land fulltime.
Grizzly Guy
No it wont.
You need to find out your exact usage of your appliance, and capacity of your battery.
Make sure your inverter is also a battery charger for your geny.
Do it right the first time. It's less expensive.
Also consider: using the freezer as a freezer and putting frozen 2 liters into your cooler. It'll be more efficient than a fridge
You need to find out your exact usage of your appliance, and capacity of your battery.
Make sure your inverter is also a battery charger for your geny.
Do it right the first time. It's less expensive.
Also consider: using the freezer as a freezer and putting frozen 2 liters into your cooler. It'll be more efficient than a fridge
I know that 200 kwh is 200,000 watt hours per year. 200,000 divided by 365 = 550 watts per day. I think I need 1100 watt hours of battery minimum. 1100 divided by 12 volts = 92 amp hours, if this is correct. I know I don't want to discharge more than 50 %, so maybe 200 amp hours?
It's easy to tell someone to do it right, but harder to help someone actually figure out what they need. That is why I'm trying to find out. The minimum I need, so I can build a system slightly larger and not spend money I can't afford.
It's easy to tell someone to do it right, but harder to help someone actually figure out what they need. That is why I'm trying to find out. The minimum I need, so I can build a system slightly larger and not spend money I can't afford.
Your first move is to get a killawatt meter and plug in the frig and see how. Much power it uses in 24 hours.
Most frig / frezzers use about 125 watts running sooooooo they run about half the time 1500watts a day plus losses 20%
A freezer may run a little less .
With out doing a bunch of math , I think your minimum size system would be 2 300 watts panels 2 golf cart battery’s from Bjs a regency 100 MPpt charge controller .
Your inverter need to have search mode so it is not powered up all the time , it will make power when the frig turns on .
This will work good in the summer months not year round DEC/Jan seems like the sun was turned off here , then the snow covers the panels and I get no power .
I also freeze water bottles in the freezer and put them in a Minnie fridge to keep food cool .
I turn off both units at night to save power but really don’t have to.
As nomad said get a inverter with battery charger built in .
A24 volt inverter with 4 gcbatery would be much better .
Most frig / frezzers use about 125 watts running sooooooo they run about half the time 1500watts a day plus losses 20%
A freezer may run a little less .
With out doing a bunch of math , I think your minimum size system would be 2 300 watts panels 2 golf cart battery’s from Bjs a regency 100 MPpt charge controller .
Your inverter need to have search mode so it is not powered up all the time , it will make power when the frig turns on .
This will work good in the summer months not year round DEC/Jan seems like the sun was turned off here , then the snow covers the panels and I get no power .
I also freeze water bottles in the freezer and put them in a Minnie fridge to keep food cool .
I turn off both units at night to save power but really don’t have to.
As nomad said get a inverter with battery charger built in .
A24 volt inverter with 4 gcbatery would be much better .
don't forget about the surge power it needs when the compressor initially kicks on.
you'd be money ahead to just buy a 12v fridge or dual power (propane) one from an RV to begin with. $50 and done.
you'd be money ahead to just buy a 12v fridge or dual power (propane) one from an RV to begin with. $50 and done.
Sarco did a good write up.
https://www.survivalistboards.com/showthread.php?t=608841&highlight=solar
https://www.survivalistboards.com/showthread.php?t=608841&highlight=solar
I was told to get a killawatt and I would but I don't have AC power, if I had power I wouldn't need solar.
Was told that it won't work in winter even though I said for summer cold water. Cold water has never been a problem in winter.
Was told the freezer would use 1500 watts a day. That's 547 kwh a year. In the first post I stated the energy star says the freezer uses 200 kwh per year, and I rounded up to 200 from the actual figure of 193 kwh.
Was told to just buy a 12 volt freezer, who does that when they are on a budget? I have everything I need except solar panels and batteries. I bet that guy is debt.
I thank the people who helped, and wonder why others post without knowing anything about what their posting about?
Was told that it won't work in winter even though I said for summer cold water. Cold water has never been a problem in winter.
Was told the freezer would use 1500 watts a day. That's 547 kwh a year. In the first post I stated the energy star says the freezer uses 200 kwh per year, and I rounded up to 200 from the actual figure of 193 kwh.
Was told to just buy a 12 volt freezer, who does that when they are on a budget? I have everything I need except solar panels and batteries. I bet that guy is debt.
I thank the people who helped, and wonder why others post without knowing anything about what their posting about?
You said you have a generator and an inverter, so you do in fact have AC power.
You can do the testing while running the generator and determine the actual wattage used instead of relying on some Energy Star estimate.
The following assumes you are using an external thermostat to turn the inverter on and off, instead of the freezer. If you leave the inverter on all the time, and it uses 10w at idle it will increase your power needs by almost 50%.
If the 200kwh a year figure is accurate and you want a cheap system, get 2 GC2 flooded batteries and a 200w solar kit.
Example system for around $440 excluding battery cables, with the option to add another 100w if it's not quite enough.
https://www.samsclub.com/p/duracell-golf-car-battery-group-size-gc2/prod3590228 - You need 2, wired in series to get 12v since these are 6v batteries
https://www.amazon.com/WindyNation-...nnectors/dp/B00FAR7650/ref=sr_1_6?keywords=200w+solar+kit&qid=1573088243&sr=8-6
200kwh/yr= 547wh/day.
200w of solar should easily produce 550w of usable power on sunny days, so you should have some extra to use for other things like phone charging, lights, etc and make up for cloudy days.
215ah of 12v batteries equals just over 2500wh of power, but you shouldn't discharge a lead acid over 50% if you want it to last, so call it 1250wh of power, which is enough for 2 days of refrigeration.
If the 200kwh a year figure is accurate and you want a cheap system, get 2 GC2 flooded batteries and a 200w solar kit.
Example system for around $440 excluding battery cables, with the option to add another 100w if it's not quite enough.
https://www.samsclub.com/p/duracell-golf-car-battery-group-size-gc2/prod3590228 - You need 2, wired in series to get 12v since these are 6v batteries
https://www.amazon.com/WindyNation-...nnectors/dp/B00FAR7650/ref=sr_1_6?keywords=200w+solar+kit&qid=1573088243&sr=8-6
200kwh/yr= 547wh/day.
200w of solar should easily produce 550w of usable power on sunny days, so you should have some extra to use for other things like phone charging, lights, etc and make up for cloudy days.
215ah of 12v batteries equals just over 2500wh of power, but you shouldn't discharge a lead acid over 50% if you want it to last, so call it 1250wh of power, which is enough for 2 days of refrigeration.
You need more panel. Likely 300 watts and one more battery to maintain a constant power without killing the battery. My solar array consists of 2-300 watt panels and a four battery 48 volt bank. This will run my fridge, internet/tv ceiling fan and lights. If there are a few days without much sunlight, then have to cut back tho.
You will need to find out the daily usage and crunch numbers in your area for sunlight hours to get a real number. There are a ton of fudge factors that keeps you from draining the battery bank. But for anything more than lights, and charging your phone, need stepped up to 24 volts or more with adequate solar charge capacity.
You will need to find out the daily usage and crunch numbers in your area for sunlight hours to get a real number. There are a ton of fudge factors that keeps you from draining the battery bank. But for anything more than lights, and charging your phone, need stepped up to 24 volts or more with adequate solar charge capacity.
Hi grizz , yes you should get a kw meter so you know how much power your freezer uses , the energy stickers lie .
I tak my km meter to lows ad plug it in , you do not need power on site .
A freezer stays closed you can’t keep getting tasty cool drinks on a hot day and stay in that energy rate .
You said you wanted to power a freezer next summer you did not say you wanted cool drinks only in the summer ?
I like cold drinks all year round and don’t want to go out in my yard to get one in the snow.
The 3 frig freezers I have used did not come close to there energy Rate sorry to say .
2 sams club gc215s are a little small to run your freezer sooooooooo you really need to get more battery .
The cheapest way to do that is buying 4 gc215 ah battery’s from sams club 89$ US .(I use 20 of these in 2 systems .
You really need 11/2 times your dally needs to make a reliable system for your frig .
You will not run your frig with 200 watts , when you miss a day of sun you will have to run the frig the next day plus bring the battery up close to full .
A 295 watt panel will not really do a good job soooooo you really need to get 2 panels .
My 295 watt panels came from a local supply house for 135 and 167$ us
I drove in and picked them up .
A mppt charge controller is really a must have item . You can gain 30% more power from them .
I was living on 2 gc215 3/4 days a week for 31/2 years and it worked real good for me but the frig was a no go .
I read SARCOS post he is in the desert in my location it did not work .
Not to be a downer but the freezer to frig Dosent really work the food stays cold but The chest freezer grows mold and the unit condensates to the point of rusting out .
Use a Minnie frig with a real freezer on top .
And yes I do really know what I’m talking about my beer is cold winter and summer and there is no need to go out side . Good luck with your project
Well built
I tak my km meter to lows ad plug it in , you do not need power on site .
A freezer stays closed you can’t keep getting tasty cool drinks on a hot day and stay in that energy rate .
You said you wanted to power a freezer next summer you did not say you wanted cool drinks only in the summer ?
I like cold drinks all year round and don’t want to go out in my yard to get one in the snow.
The 3 frig freezers I have used did not come close to there energy Rate sorry to say .
2 sams club gc215s are a little small to run your freezer sooooooooo you really need to get more battery .
The cheapest way to do that is buying 4 gc215 ah battery’s from sams club 89$ US .(I use 20 of these in 2 systems .
You really need 11/2 times your dally needs to make a reliable system for your frig .
You will not run your frig with 200 watts , when you miss a day of sun you will have to run the frig the next day plus bring the battery up close to full .
A 295 watt panel will not really do a good job soooooo you really need to get 2 panels .
My 295 watt panels came from a local supply house for 135 and 167$ us
I drove in and picked them up .
A mppt charge controller is really a must have item . You can gain 30% more power from them .
I was living on 2 gc215 3/4 days a week for 31/2 years and it worked real good for me but the frig was a no go .
I read SARCOS post he is in the desert in my location it did not work .
Not to be a downer but the freezer to frig Dosent really work the food stays cold but The chest freezer grows mold and the unit condensates to the point of rusting out .
Use a Minnie frig with a real freezer on top .
And yes I do really know what I’m talking about my beer is cold winter and summer and there is no need to go out side . Good luck with your project
Well built
I converted a 3.8 cu ft freezer to use as a refrigerator. It was rated to consume 540 watts/day (197 KWh/yr) as a freezer. After conversion I tracked consumption using a Kill a watt on a day with a high of 90 (no ac on in the trailer), and it consumed 310 watts that day. My solar/battery system was one 265w panel and two 6V costco golf cart batteries (approx 225 ah). That system easily kept the batteries charged during the day and had plenty of charge left in the morning.
Based on that, one 100W panel and 225AH of golf cart batteries could keep the fridge running with ideal charging conditions but I'd prefer 200W+ to provide a safety margin. Also consider what else you want to run besides the fridge and the potential for shade or clouds to reduce solar charging.
Warning that the 1000W inverter MAY not be enough to handle start-up surge. My initial 800W inverter was NOT enough, so I went to 1200W which handled it well. Since you already own it, try the 1000W and see how it works for you. Just recommend thorough testing before risking spoilage on your first outing.
Best of luck, freezer conversion seemed very energy efficient for me.
Based on that, one 100W panel and 225AH of golf cart batteries could keep the fridge running with ideal charging conditions but I'd prefer 200W+ to provide a safety margin. Also consider what else you want to run besides the fridge and the potential for shade or clouds to reduce solar charging.
Warning that the 1000W inverter MAY not be enough to handle start-up surge. My initial 800W inverter was NOT enough, so I went to 1200W which handled it well. Since you already own it, try the 1000W and see how it works for you. Just recommend thorough testing before risking spoilage on your first outing.
Best of luck, freezer conversion seemed very energy efficient for me.
200kwh/year = 22.8 watts/hr 24/7
However, you need to define WHERE the unit will be run. My 28 cu ft double door fridge/freezer average 59 watts/hr in winter and 76 watts/hr in summer. What causes that 32% difference? House is 68F winter and 78F in summer. That freezer's rating is for a home environment so probably not above 78F. What temperature will you be using it in? If you can find the testing standard, you might be able to find the temperature at which they determined that power usage.
If we extrapolate from my fridge/freezer, running it at 88F would be another 32% increase or now 100 watts/hr. At 98F that would be 132 watts/hr.
You really do need to use a Kill-A-Watt or similar to check the power draw of an appliance AS YOU WILL USE IT. You said "inverter" so I'm talking AC power and the Kill-A-Watt is king. Lowe's might not look kindly at you rolling the freezer out in the hot asphalt parking lot and running a LONG extension cord for power, but perhaps that's what you should do.
At the 22.8 watts/hr average draw, 180AH would last about 27 hours and you would need 300 watts of solar if you have 5 hours of sun and 500 watts of solar if you have 3 hours of sun. YOU HAVE NO CUSHION FOR A RAINY DAY. Cushion would require doubling the battery bank (360AH) and doubling the solar power to be able to charge two days' use in one day of sun in case the next day is rainy. If you don't want to plan for clouds and rain, forget solar and use an inverter generator.
Using the 32% increase per 10F ambient temperature increase, a 10F increase would take the average power to 30 watts/hr and 180AH would last 22.6 hours. Another 10F increase would take the power to 39.7 watts/hr and 180Ah would last 18.5 hours. Another 10F increase would take the power to 52.4 watts/hr and 180AH would last 14.9 hours and you would need a minimum of 500 watts of solar to keep the batteries charged day by day.
Because your inverter has some amount of idle current (power it uses whether or not running a load) I'm including a 1.2 amp steady state idle current (high end for an inverter that size) in these figures.
In response to solar panels delivering 20-25% less than their ratings: Those ratings are STC (Standard Test Conditions) which specify 1000 lumens of illumination and the panels at 25C. If the panels is in the sun and it's not freezing, they will be warmer than that and produce less power. For planning, you should use the NOCT rating (is the panel doesn't have one, multiply the rated power by 0.73 to get the NOCT value. What you get depends on the panel type, the maker, the wind and you local sunshine. I have "100 watt" panels from four different makers that never do better than 75 watts in backyard sun (real world testing). However, I have two Jinko 250 watt panels that each deliver 235 watts in that same location (that's 94% of rating). Ignore wattage ratings on the panels from banggood.com and the like as they are nearly always inflated. The Imp and Vmp say it's 49 watts and the copy says 100 watts. Also their DC-AC inverters. Their is a "4000 watt" inverter that has 'Do not exceed 550 watts" in the fine print. Definitely read ALL the fine print.
I use a (very complex) spreadsheet that I created to get the runtime for a given battery bank and a given load. It uses 90% inverter efficiency (tested value of the inverter I use at the power levels it is used at - the efficiency goes down as the load exceeds 50-60% of the inverter's capacity). You can download the 12 volt version that spreadsheet here: http://www.jecarter.us/files/My-Solar-Generator.xls There's also a version for higher voltage battery banks but it doesn't get updated often.
Your battery runtime is also affected by how heavily it is loaded. A 100AH battery is speced to deliver 5 amps for 20 hours. It will NOT deliver 10 amps for 10 hours or 20 amps for 5 hours unless you're using high discharge lithium batteries. Battery operation is based on a chemical reaction and that reaction is limited by the design of the plates and the method of keeping the electrolyte in place against those plates (or films or whatever that specific battery's construction is).
If you just want the "cool" mentioned in a later post, get a freezer to fridge conversion kit (separate thermostat in the fridge temperature range) and run that freezer as a fridge. It will run less because it's not getting as cold. You don't lose the cool when you open the door as you do when you open a fridge. Probably less then $50 and you might find it listed under "freezer to fridge" or "freezer to kegerator".
However, you need to define WHERE the unit will be run. My 28 cu ft double door fridge/freezer average 59 watts/hr in winter and 76 watts/hr in summer. What causes that 32% difference? House is 68F winter and 78F in summer. That freezer's rating is for a home environment so probably not above 78F. What temperature will you be using it in? If you can find the testing standard, you might be able to find the temperature at which they determined that power usage.
If we extrapolate from my fridge/freezer, running it at 88F would be another 32% increase or now 100 watts/hr. At 98F that would be 132 watts/hr.
You really do need to use a Kill-A-Watt or similar to check the power draw of an appliance AS YOU WILL USE IT. You said "inverter" so I'm talking AC power and the Kill-A-Watt is king. Lowe's might not look kindly at you rolling the freezer out in the hot asphalt parking lot and running a LONG extension cord for power, but perhaps that's what you should do.
At the 22.8 watts/hr average draw, 180AH would last about 27 hours and you would need 300 watts of solar if you have 5 hours of sun and 500 watts of solar if you have 3 hours of sun. YOU HAVE NO CUSHION FOR A RAINY DAY. Cushion would require doubling the battery bank (360AH) and doubling the solar power to be able to charge two days' use in one day of sun in case the next day is rainy. If you don't want to plan for clouds and rain, forget solar and use an inverter generator.
Using the 32% increase per 10F ambient temperature increase, a 10F increase would take the average power to 30 watts/hr and 180AH would last 22.6 hours. Another 10F increase would take the power to 39.7 watts/hr and 180Ah would last 18.5 hours. Another 10F increase would take the power to 52.4 watts/hr and 180AH would last 14.9 hours and you would need a minimum of 500 watts of solar to keep the batteries charged day by day.
Because your inverter has some amount of idle current (power it uses whether or not running a load) I'm including a 1.2 amp steady state idle current (high end for an inverter that size) in these figures.
In response to solar panels delivering 20-25% less than their ratings: Those ratings are STC (Standard Test Conditions) which specify 1000 lumens of illumination and the panels at 25C. If the panels is in the sun and it's not freezing, they will be warmer than that and produce less power. For planning, you should use the NOCT rating (is the panel doesn't have one, multiply the rated power by 0.73 to get the NOCT value. What you get depends on the panel type, the maker, the wind and you local sunshine. I have "100 watt" panels from four different makers that never do better than 75 watts in backyard sun (real world testing). However, I have two Jinko 250 watt panels that each deliver 235 watts in that same location (that's 94% of rating). Ignore wattage ratings on the panels from banggood.com and the like as they are nearly always inflated. The Imp and Vmp say it's 49 watts and the copy says 100 watts. Also their DC-AC inverters. Their is a "4000 watt" inverter that has 'Do not exceed 550 watts" in the fine print. Definitely read ALL the fine print.
I use a (very complex) spreadsheet that I created to get the runtime for a given battery bank and a given load. It uses 90% inverter efficiency (tested value of the inverter I use at the power levels it is used at - the efficiency goes down as the load exceeds 50-60% of the inverter's capacity). You can download the 12 volt version that spreadsheet here: http://www.jecarter.us/files/My-Solar-Generator.xls There's also a version for higher voltage battery banks but it doesn't get updated often.
Your battery runtime is also affected by how heavily it is loaded. A 100AH battery is speced to deliver 5 amps for 20 hours. It will NOT deliver 10 amps for 10 hours or 20 amps for 5 hours unless you're using high discharge lithium batteries. Battery operation is based on a chemical reaction and that reaction is limited by the design of the plates and the method of keeping the electrolyte in place against those plates (or films or whatever that specific battery's construction is).
If you just want the "cool" mentioned in a later post, get a freezer to fridge conversion kit (separate thermostat in the fridge temperature range) and run that freezer as a fridge. It will run less because it's not getting as cold. You don't lose the cool when you open the door as you do when you open a fridge. Probably less then $50 and you might find it listed under "freezer to fridge" or "freezer to kegerator".
Notyoung, Thanks this helped. I ordered a Johnson control to turn it to a fridge. If I have a cloudy day or rain, I can charge with a generator. Didn't think about the temp affecting the power usage, all I could do is set it in the shade until I get a shed built. Also I could turn it off at night. Also if cloudy days, with a low battery, I can just drink air temp water. I'm just really hoping for cold water on the hot 90 to 100 degree humid days.
Well, I'm not Nomad and I agree with him. I've a degree in Electronics and worked in it over fifteen years. An appliance's run current and start current are two different things, start current draw can easily be more than twice the run current and if your inverter can't supply it guess what! If you don't want to listen to solid advice you're just setting yourself up for a fall. Get a kilowat meter and find out just what demands need to be met and plan for that. You are using figures based on an 24/365 average and your system doesn't run like that, it only runs a few hours a day and uses all the energy in just those few hours. But do however you want, just don't expect to blame us for your failure.
I was reading the thread and came to the realization that I was out of line with a few people. I don't know why, I guess my life hasn't been going great. But that isn't a excuse to treat people bad. I hope Nomad2 and any others I offended can forgive, or at least give me another chance. I will stop being a *******.
I’m glad you came around , I hope things turn around for you .
Apologies accepted .
A shed and a pond is a good start , I catch water off a deck roof in front of my ( free to me ) vintage air stream Trailer .
Drinking water comes from home or a spring on the side of the road .
I just built a generator shed out of rough sawn lumber , it dident really cost much .
It’s nice to get all set up so you can just work when you are at you property .
I built The house out of rough sawn hemlock with my son a daughters.
We used 2x6 2x4s for walls and 3/4 ply wood on the out side .
The roof is 5/8 ply wood .
Every thing else was cut from the surrounding area and nailed up the same day .
I bought a lot of stuff at material actions and off crags list .
Apologies accepted .
A shed and a pond is a good start , I catch water off a deck roof in front of my ( free to me ) vintage air stream Trailer .
Drinking water comes from home or a spring on the side of the road .
I just built a generator shed out of rough sawn lumber , it dident really cost much .
It’s nice to get all set up so you can just work when you are at you property .
I built The house out of rough sawn hemlock with my son a daughters.
We used 2x6 2x4s for walls and 3/4 ply wood on the out side .
The roof is 5/8 ply wood .
Every thing else was cut from the surrounding area and nailed up the same day .
I bought a lot of stuff at material actions and off crags list .
I have 7 100 watt panels on a extended van. 6 235 amp 6 volt batteries and 2 30 amp controllers. Split the system so each is independent of the other. The 300 watt side will run a 7 cubic foot freezer but the controller never goes into float stage very often , about once every three days if its real sunny. The 400 watt side will float everyday. This is this is this year data from Albuquerque this summer into fall. I have never broke the batteries into smaller sets ,so this is just about the solar panels. I would guess that 4 batteries would be the least I would get for cloudy days factor. This is with a 2000 watt inverter from Harbor Freight. It barely lights up 2 bars when it is running. did the kilowatt thing on it but I cannot remember how long it ran each day.
A second thought , champion makes a 1800 watt generator that is easy on fuel .
I never really tried to run a small frig off it but I think it would work .
I ran one at the house for lights tv radio and small tools .
I think it cost 168 bucks plus tax on sale .
It ran 15 hours a day while we where there for a few years .
If you just have drinks in the frig you could cool it down twice a day , and it’s not a big deal if it gets warm .
I’m sure you could find a spring in your area for cool water .
Here the DEC marks springs with blue paint on gard rails a telephone poles
We used a 4650 watt champion for compressors and saws .
It burns 3 gallons a day working intermittently with power tools .
I never really tried to run a small frig off it but I think it would work .
I ran one at the house for lights tv radio and small tools .
I think it cost 168 bucks plus tax on sale .
It ran 15 hours a day while we where there for a few years .
If you just have drinks in the frig you could cool it down twice a day , and it’s not a big deal if it gets warm .
I’m sure you could find a spring in your area for cool water .
Here the DEC marks springs with blue paint on gard rails a telephone poles
We used a 4650 watt champion for compressors and saws .
It burns 3 gallons a day working intermittently with power tools .
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