Solar help

[helomech]

We are about to put together our first real solar system. We want to get a system that will run 2 chest freezers. One is large, and the other is smaller. I will get the wattage tomorrow. I don't know where to start. Please throw all ideas at me. Don't mind making it a little larger if it doesn't cost much more.

[Domeguy]

Are you planning to run them full time from solar/battery power? Are they DC powered or AC powered? Are the two freezers near each other, or are they at different ends of the house? Do you plan to run them together from the same battery, or two seperate battery's due to distance? You say your first real solar system...do you plan to power any thing else?

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[helomech]

Are you planning to run them full time from solar/battery power? Are they DC powered or AC powered? Are the two freezers near each other, or are they at different ends of the house? Do you plan to run them together from the same battery, or two seperate battery's due to distance? You say your first real solar system...do you plan to power any thing else?

Full time, but will have a power supply from 110volt if it needs it. I don't want it to have to ever use the 110 volt help though. They are right next to each other in a small shed outside in our well house. I am thinking of building a rack over the shed to hold the panels. I would love to run other things, but it is not a priority.

I have a xantrex 40 amp truecharge2, that will be hooked to the battery and will kick on if the batteries get low. But like I said above I don't want it to ever kick on. I want this to run in a long term grid down situation.

Was thinking keeping them each on their own system, but don't really have a preference.

[bacpacker]

I think DG is our resident expert on Solar. I surely scribe to Home Power Magazine. They have articles on sizing systems all the time. You might check them out online and see if they have a archive section.

Another tip you may need to do. Get a "kill a watt" meter. It us in your wall socket, then you plug your appliance into it. Run it for a day and it will give you a true reading of power useage.

[Vodin]

Battery Bank (multiple batteries) and an inverter are needed as well.

[helomech]

I can't find the stickers on the freezer, but one is a kenmore elite and the web site says it uses Kilowatt Hrs. per Year:306 and the other freezer is about half the size, but older. It is a woods model.

[bacpacker]

The Kilowatt will give you an exact reading. You can run it for hours or days and make your calculations from there. They are highly recommended to determine your total loads to size any type renewable power source.

[helomech]

Thanks bacpacker, we are going to pick one up next time we are in town. Probably Monday.

[bacpacker]

I am really interested in following your choices here. Running our freezers are high our list of coverage needs.

[helomech]

According to the numbers domeguy came up with it is going to be to expensive to justify. He is thinking around 3-4k per freezer.

[Domeguy]

Here are the numbers I came up with. The column on the left is for one freezer, and 2 freezers on the right.
http://i48.photobucket.com/albums/f226/gantsum/76f92a18323571cf19b4136d5f325999_zpshyec2eyu.jpg

Approx $4876 for 1 freezer. Approx $9460 for 2 freezers. This does not include any roof racks, wiring, electrical panels, fuses, shut off switches, ect.
These figures are from one store only. You would need to check around to find the best prices.

[jamesneuen]

What size freezer did you get the numbers from? Those are kind of discouraging numbers for just a few freezers. lol. I wanted to have my entire house running on solar.

[helomech]

Thanks Domeguy.

[Domeguy]

What size freezer did you get the numbers from? Those are kind of discouraging numbers for just a few freezers. lol. I wanted to have my entire house running on solar.

Part of the high cost is the inefficiency problem. In a entire house, you can spread it out over a wider range. Although the total cost for the entire home is high, it won't be exponentially as high as this is. I hope that makes sense.

[jamesneuen]

Kind of. But I'm no electrician. I know solar panels themselves aren't very efficient but that's about it.

[Domeguy]

With DC power, You loose a percentage of the efficiency at the panels, at the inverter, the battery's, the wiring, all along the system. This is why we as a nation use AC power. During the power battles that started between Thomas Edison and Nicholas Tesla, Edison's DC power had to have a power station booster every couple of miles to keep up the voltage, where as Teslas AC system had very little power loss. Edison tried to show how dangerous the AC power is by publicly electrocuting large animals, even electrocuting an elephant to try to scare the public into using his system, but he ultimately lost and Tesla built his first AC electrical grid around Niagra Falls, NY.

[jamesneuen]

So by that reasoning you should station your panels and battery bank as close together as possible, with the inverter pretty much wired directly to the battery by the shortest means possible? Then if you wired the panels in-line with each other they would only have an additional foot or two instead of traveling the entire system?

I think I understand what you mean about the losses but would increasing the diameter of the DC wire reduce the resistance and make it more efficient or would that only work to a certain point?

[Domeguy]

Yes...and no. You would want the system components close to each other, Within reason. The panels are only X % efficient, no matter where there are placed, as also is the inverter. Battery's are also X% efficient! and together! these three things will bring the entire system to maybe 85-90% efficient, which is not to bad these days as it used to be a lot worse. The wiring however is a different matter. You would want the components as close together within reason, and as close to the power panel as possible. This is because you have a choice in the voltage drop in the wiring, just as you do not in the rest of the system. You can keep the wiring voltage drop down to 2-3 % by choosing the proper wiring size (or gauge), the length of the wiring run, and how much current you have flowing in the wire.
Your question and answer about wire size is correct. Choosing a wire to small will drop the current flow and cause the wire to overheat, which could then catch fire. But on the other hand, choosing a wire to big will also cause voltage drop just because it is too big, and would just cost you more money. The key to this delicate dance is " within reason". If you have to have the panels 300 feet away from the house you are trying to power, than they will have to be 300 feet away. Just do the math and choose the correct wire and realize there will be voltage loss, and suck it up like a big boy. But at the same time, connecting everything as close as possible would just cause the instillation to be a nightmare. The panels need to be outside, and USUALLY, the rest of the components should be inside away from the weather. So it's ok to separate them with a length of wire or cable WITHIN REASON. Also most people would not want to see the components of the system in their living room, even if this would be the most efficient wiring run. Most people would want to place the components in their garage, then run the wiring to the electric panel.

[jamesneuen]

Wow, I apparently need to take some electrical classes. Know of any free online classes?

I know there is a balance of voltage and amps to choose a correct wire size, so in a 12 volt base system what is the amperage based off of? And for any decent size current that would have to be a big wire till it is converted to AC. Or does the amperage and volts only work for AC?

[Domeguy]

Wow, I apparently need to take some electrical classes. Know of any free online classes?

I know there is a balance of voltage and amps to choose a correct wire size, so in a 12 volt base system what is the amperage based off of? And for any decent size current that would have to be a big wire till it is converted to AC. Or does the amperage and volts only work for AC?

I'm not sure of your question, but if you are asking where does the total amperage come from, it comes from the total solar panels and how they are hooked up, ie, in series or in parallel. Wired in series, the voltage goes up, but the amperage stays the same. In parallel, the amperage goes up but the voltage stays the same...maybe these pictures will help.
http://i48.photobucket.com/albums/f226/gantsum/c3b45cbc206e69ac4e132e8ce89b19af_zpssyj1178i.jpght tp://i48.photobucket.com/albums/f226/gantsum/250acbcf684a39420bb8ae52a4e12ebf_zpswyt4b23j.jpg
http://i48.photobucket.com/albums/f226/gantsum/1168fc7925d49df4271d7f6ed73e269a_zpsymc4y2wk.jpght tp://i48.photobucket.com/albums/f226/gantsum/3ceebfddb7377e89904d65a5c563870d_zpsohvvfjgg.jpg

[Domeguy]

You determine what size wire to use after you know what size panel you are going to use and know the total watts and amperage they will kick out. You also need to know how long the wire will need to run. You can then cheat and use charts like this.
http://i48.photobucket.com/albums/f226/gantsum/43e9ad2ca6664e76411a30efc8f7b482_zpsepz1ycje.jpg

If you needed 6 amps, and the wire run distance was 42 feet, in order to get a 2% voltage drop! you would use a #8 wire.
For anyone who is interested in learning about solar installation, I highly recommend this book. It explains everything in easy to understand language. It is the book I always reach for when I need to check something.
"Photovoltaics Design & Installation Manual" put out by Solar Energy International. Published by New Society Publishers. Their phone # 1-800-567-6772 , and they are based out of Canada.
http://i48.photobucket.com/albums/f226/gantsum/03f0b09702aea944dcacf676f5aacc75_zpswdcvs2ll.jpg

[jamesneuen]

Ok so it's like with batteries to get higher amps or volts. If similar panels output all 12 volt, will the size determine the amperage?

Sorry to beat a dead horse.

[jamesneuen]

I'll have to get a few books I think. Or maybe buy an electrician a few beers

[Domeguy]

On the back of every panel, usually near the wiring hookup junction box will be a sticker with all the information of the panel on it. It will look like this.

http://i48.photobucket.com/albums/f226/gantsum/430e5399f01f2e4572ebfcda59da4a11_zpsfxumhord.jpg.

I copied this from the web so I don't have to type it all.



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11-23-2008, 12:53 PM #1
ASUgrad
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Nov 2008
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Solar Panel Hookup. Series or Parallel?
Hi, I was wondering what would be the best way to hook up a solar panel system for maximum production. From what I understand it comes down to either series or parallel. Thank you.

Jackie
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11-24-2008, 10:00 PM #2
SolarGuy
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Oct 2008
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Re: Solar Panel Hookup. Series or Parallel?
Hello Jackie and thanks for joining Solar Panel Talk. I'll explain briefly what the two mean.

Series wiring is when you connect a positive terminal from one solar panel and connect it to the negative of another. Doing this will result in higher voltage (the sum of voltage from the panels) while the amps stay the same.

Parallel wiring is when you connect a positive with a positive and a negative to a negative. When you do this the voltage remains the same, meanwhile the you get higher amps. So two 12 volt/3.5 amp panels hooked up in parallel would output 12 volts at 7 amps. Four panels hooked together would produce 12 volts at 14 amps and so on.

Hopefully that will help you in deciding which way you want to hook them up.
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12-13-2008, 02:11 PM #3
D_Robbins
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so why would you want more voltage compared to amps and vice versa?
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02-02-2009, 10:04 AM #4
Greg
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Series or parallel
Just to see this clearly....sorry to be a bit thick.....but does this mean one runs series to charge batteries, and parallel to run appliances directly?
Thanks J.SUN
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02-03-2009, 06:39 PM #5
solar_geoff
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Your module and inverter combination dictates how you should wire everything. These modules wired in series are called "strings." The number of modules per string is dictated by your inverter operating voltage window. For example, SMA inverters have a DC voltage window of between 250-600V. Your maximum number of modules per string is controlled by the module open circuit voltage (Voc) adjusted for your lowest record temperature (600v/Voc x NEC 690.7 correction factor). The minimum number of modules per string is controlled by the module max power voltage (Vmp) adjusted for your hottest record temperature. The Voc and Vmp correction factors are found on the module data sheet.

It is always good practice to add 10-20% to your turn-on voltage to account for the drop in output that the modules will experience over 20-30 years (usually 10-20%).


Once you have determined your number of modules per string, you then add strings in parallel. You do not want to add to many strings because your inverter can only produce power up to it's nameplate wattage (with a few exceptions). Basically you want to make sure your AC wattage is as close to your inverter rating as possible, so that you are not paying for DC watts not converted to AC electricity. It will not, however, damage the inverter to exceed its maximum usable current. You could have 1000 strings wired to a 2000w inverter and not damage it, as long as your number of modules per string falls into the inverter DC operating voltage range. The reason for this is that the inverter is able to "throttle" the current flowing through it with capacitors. Any power in excess of the inverter's capacity is simply not created.

To determine your AC wattage: (#modules)x(module PTC wattage)x(inverter efficiency)

Whew!
End copy!

Now refer to the above picture from my previous posting with 2.4 series and parallel circuits in power sources. Look at figure 2-2. Each panel will put out 12VDC and 3A. It shows 2 panels hooked up in series. The voltage now will be 24V but the amps will stay at 3A. 3 panels together in series would make it 36V, 4 panels would make 48V, but the amps will still be 3A.

In figure 2-3, the same 2 panels are wired in parallel. The output now is 12V, but the amperage now is 6A. Add a third panel and you will have 9A, add a 4th panel, you will have 12A, but the voltage will still stay at 12 volts.

Solar panels wired in series will increase the voltage, but the amperage will stay the same.
Solar panels wired in parallel will increase the amperage, but the voltage will stay the same.

[jamesneuen]

Oooooo that I can understand. But will 12 volts at 6 amps transfer the same amount of power as 24 volts at 3?

[Domeguy]

Sorry, but no. Let's go to the definition of what volts, watts, resistance, and amps are:
Voltage: the electrical pressure that forces electrons to flow. Voltage is sometimes called electromotive force.
Watts: A watt is a unit of measurement of electrical power. 746 watts is equal to 1 horsepower.
Ampere: the rate of flow of electrons through a circuit. One ampere is equal to the flow of 1 coulomb (628 X 10 to the 16 power, or 10 with 16 zeros electrons) per second.
Resistance: the opposition to current flow of electrons. A unit of measurement of resistance is the ohm.
So let's make a small model. Think of a house in a valley. The house get it's water from a water tank next to the house by way of a direct pipe to the tank. The house has a sink, and the sink has a faucet. Depending on how much water is in the tank determines how much water pressure comes out of the faucet. If the tank is full, the pressure will be high. If the tank is low, the pressure will be low. Now think of the tank as the power source, and the pipe as the amperage, and faucet as the watts, and a leak in the pipe as resistance. If you increase the amount of water in the tank, or voltage, the amount of water coming through the pipe is determined by the size of the pipe, so to increase the amount of water, or amperage, you need to increase the size of the pipe. Once you get the amount of water flowing through the pipe you want, you can open the faucet to get you correct amount of water, or watts. I hope this makes any sense.

[jamesneuen]

But by that reasoning a 2 inch pipe flowing at 60 psi would generate the same water at the end result as 4 inch pipe at 30. The only difference is the faucet/watts and the hole/resistance.

I think I just need to take some electrical classes because my brain is starting to hurt. lol.

Thank you for trying to help and I do understand a few things better but I don't really have a knowledge base to start it on for deeper understanding.

[Domeguy]

As I stated in the beginning, I am in no way an expert, and it may have forgotten more than I learned over 5 years ago. I may not have expressed that analogy correctly as I was trying to remember how an instructor explained it to us, and I may have gotten a bit of it wrong. But I can't stress enough what help a GOOD book on solar power is. And I can guarantee the photovoltaic book I mention above, and here again.

Photovoltaics Design and Installation Manual
Published by New Society Publishers
P O Box 189. Or. Solar Energy International
Gabriola Island, BC. PO Box 715
V0R 1x0, Canada. Carbondale, CO. 81623-0715
1-800-567-6772. 970-963-8855
www.new society.com. www.solarenergy.org

You can get it from the publisher here
http://i48.photobucket.com/albums/f226/gantsum/1f376dad88e9fffa74c04bae415f9db8_zpsvt9zlwl6.jpg

Or from Amazon for a lot cheaper.
http://i48.photobucket.com/albums/f226/gantsum/eac6d1cb5f3725a0e7c1c87ca807852b_zpsvhpo7u6j.jpg

It is well worth the money.

[Kesephist]

Maybe I'm not getting it properly... the solar power layout you folks are all touting is photovoltaic, sunlight to electricity direct.

Is there out there a solar to steam to turbine power layout that doesn't cost a bleedin' fortune?

Kesephist

[Domeguy]

Not unless you consider several hundred million cheap.http://i48.photobucket.com/albums/f226/gantsum/e90f704e3534aa4ecd23cb3bc399759d_zpstr3u1b08.jpg

[Domeguy]

Oooooo that I can understand. But will 12 volts at 6 amps transfer the same amount of power as 24 volts at 3?

I have gone through these postings hoping I had made some math errors, and in my answer on this question, I was wrong, somehow I misread the question, or just had a brain fart. The answer Is most definately YES
One of the most basic rules of electricity is POWER = WATTS. WATTS = Volts x Amps

I apologize for any problems I may have caused.

[jamesneuen]

Whew. Ok so I'm not too out of my depth.

[Domeguy]

Maybe I'm not getting it properly... the solar power layout you folks are all touting is photovoltaic, sunlight to electricity direct.

Is there out there a solar to steam to turbine power layout that doesn't cost a bleedin' fortune?

Kesephist

Sorry, I didn't mean to be too blunt, but out technology to turn solar to steam is no where ready to be reduced for the home yet. You are talking about turning water to steam at many hundreds of degrees, and many lbs. of steam pressure. We do however have a way of getting close. Try researching solar evacuated tubes. They can turn sun light into heat high enough to boil it, but right now, we can only capture the hot water into a hot water tank to use for home hot water use. Anyone looking to run their entire home from solar should look into putting a system into their use, as the hot water if heated by electricity can be 20-40% of their electrical usage. Therefore, they would need 20-40% fewer power from their panels! therefore needing less panels.
http://i48.photobucket.com/albums/f226/gantsum/e457aeea1540e6e08d79572992c2a571_zpsdxcje7lq.jpg

[jamesneuen]

They have a ton of DIY ones of those too DG.

[helomech]

I plugged in one of those things in to the freezer that reads power and it says it uses 49kwh.

[bacpacker]

There is a starting point

[Domeguy]

Here are the numbers I came up with. The column on the left is for one freezer, and 2 freezers on the right.
http://i48.photobucket.com/albums/f226/gantsum/76f92a18323571cf19b4136d5f325999_zpshyec2eyu.jpg

Approx $4876 for 1 freezer. Approx $9460 for 2 freezers. This does not include any roof racks, wiring, electrical panels, fuses, shut off switches, ect.
These figures are from one store only. You would need to check around to find the best prices.

Hey Helomech, I was rereading this post after you posted your kW usage on one of the freezers. As per our phone call, you couldn't tell me the actual numbers, and we both "guessed" on the compressor running 50% of the time, and I don't remember how we came upon the number for 360 watts per hour, it may have been on one of them. But going back, I used the 168 kWh hours per month I came up with x12 months = 2016 kWh per year. But one of the tags saint it only used less than 200 kWh per year ( I can't remember the number right now). But without accurate numbers, we were guessing, and it looks like we WAY over guessed how much time the compressor would run. I will re do the numbers with the yearly KWh hrs to get the more accurate number, and get back to you in a couple of hours. You may still be in the solar business.

[helomech]

That is both freezers running on one plug. They have been running on it for almost 2 weeks now and in this heat they are working harder right now than they will the rest of the year.

[Domeguy]

Does the meter have a setting for average, or power used over a certain time? Was it using 49 kWh at that second, per hour, month, year. kWh is a term used to equate power usage over a certain time. Volts x Amps = Watts. Hours x Watts = Watt-hours or (Wh). 1000 Wh =1 Kilowatt-hour. 1 Kilowatt-hour = 1kWh. So KWh is how much power is used in a certain amount of time, rather than an amount of power. To make it simpler, the meter should have a wattage usage setting, and an amperage usage setting. These 2 numbers are what you need to get an accurate amount of power being used over a period of time to get an accurate kWh. The only problem is with an appliance using a compressor, it's difficult to get an accurate reading, as when the compressor is running, it will use more power. I hope this makes sense.

[helomech]

Will go look

[helomech]

This is the one the wife bought. http://www.walmart.com/ip/25886580?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227018143581&wl0=&wl1=g&wl2=c&wl3=40880693912&wl4=&wl5=pla&wl6=78810730832&veh=sem

Here is the data that is on it. $30.96 a month to run. $1.03 a day, $7.22 a week
187 Watts, 227 VA, 120.5 volts, 1.88 amps, 52.93kwh and 306 hours. Not sure how to tell any more than that. I don't even know what VA is.

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Wow, site was messing up.

[Kesephist]

That is both freezers running on one plug. They have been running on it for almost 2 weeks now and in this heat they are working harder right now than they will the rest of the year.

I suggest, sir, pulling all possible dodges regarding the freezers.

Separate room. Underground preferred.

Insulate all walls, ceiling and floor.

"Airlock" type entry into said room.

That's all the tricks I recall from friends and family re: keeping the freezer as economical as possible.

[helomech]

I suggest, sir, pulling all possible dodges regarding the freezers.

Separate room. Underground preferred.

Insulate all walls, ceiling and floor.

"Airlock" type entry into said room.

That's all the tricks I recall from friends and family re: keeping the freezer as economical as possible.

I don't have many options, these freezers are in a small metal shed in direct sunlight.

[cwconnertx]

Let me help, i have an engineering degree and worked as an electrician. A freezer will use about 1000 watt-hours per day or less in most cases. Also known as 1 kilowatt hour.

Older models use more, newer use less, hot locations more, cool locations less, but never 4320 watts for anything less than a industrial meat locker.

Generally 1 250 watt panel per freezer will be the bare minimum in a reasonably sunny place, less in pheonix, more in seattle. I'd size you for 800 watts of panels to give plenty of safety margin.

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Looking back at the meter posting, you have something wrong with your freezers, if that data is correct they are using 2-3 times what should be, perhaps the older one is running poorly. You can get a brand new deep freeze for 200 or 300. Youd get payback in under 2 years if the old freezer is thr problem. Try metering each separately for a week each and see if perhaps there is a problem.

[helomech]

Will Isolate them and get back on here.

[Domeguy]

Hello Cwconnertx.....With the numbers he had given me, I had typed in all the data on what I thought he would be needing as far as the # of panels, battery's, and inverter, along with some prices that day on a certain site. But for some reason, they didn't go through on the site, so I called him with the numbers. But if you can shine some light here, I can repost the numbers and see what you think. Didn't want anyone to think I was passing him off.

[bacpacker]

I made a post back then as well and it isn't showing now either. Didn't give it much thought until you mentioned it DG

[ElevenBravo]

Good thread, following... Thanks to everyone's input, has been very educational.

May I suggest for a future purchase, a propane freezer? No power needed.

EB

[Sniper-T]

how about posting those numbers up... I am interested as well.

I have an outside freezer (huge), and old Roy fridge/freezer, and a pepsi machine that I would love to run solar.

As a secondary system, I wish to put a solar aerator in my pond, something that will pump down 15 feet-ish. I remember finding one from the UK a couple years ago, but lost the link, any leads?

[cwconnertx]

Hello Cwconnertx.....With the numbers he had given me, I had typed in all the data on what I thought he would be needing as far as the # of panels, battery's, and inverter, along with some prices that day on a certain site. But for some reason, they didn't go through on the site, so I called him with the numbers. But if you can shine some light here, I can repost the numbers and see what you think. Didn't want anyone to think I was passing him off.

I saw that, your calculations were ok, but the problem was the inputs weren't quite what you should use.

1. The freezer data plate current is the maximum current, it consumes far less once running than when the motor starts.
2. I think your duty cycle was way higher than they really should run.


I can't find the stickers on the freezer, but one is a kenmore elite and the web site says it uses Kilowatt Hrs. per Year:306 and the other freezer is about half the size, but older. It is a woods model.

Looking at this kw-hr per year figure, and dividing by 365 yields 838 watts per day, even if the older smaller one is half as efficient, that should be maybe 2kwhr/day worst case, i think your estimate was based on 4320 watts per , which is high

I don't mean to step on anyone's toes. Just trying to help.

[bacpacker]

With so many of us looking at using solar at some point for various uses, I don't think input from anyone would be discouraged!

[helomech]

Good thread, following... Thanks to everyone's input, has been very educational.

May I suggest for a future purchase, a propane freezer? No power needed.

EB

Maybe so, but if the grid goes down you won't be getting any more propane. The sun will still shine.

[cwconnertx]

Maybe so, but if the grid goes down you won't be getting any more propane. The sun will still shine.

This is why I swapped out my RV fridge for a 12 volt (engel) and used solar panels rather than propane. Not just grid down, but mine sits for long periods and I don't want to run it out of propane, its a pain to get an RV tank filled, its not like swapping out a tank on a travel trailer or bbq grill. For me its the hassle more than the long term grid down scenario. But I still use propane for the stove, hot water heater, and furnace (although the furnace and hot water can run off waste engine heat, but I'd run out of gasoline to drive it before propane in any event)

I prefer solutions that have longer lives with less consumables, but nothing really lasts forever. Propane fridges do have the advantage of no real moving parts. But I have seen compressor fridges and propane fridges over 50 years old.

[Sniper-T]

our remote cabin has a propane fridge dating from the 1930's (Seville) needs occasional 'tweaking', but runs like a top!

[cwconnertx]

our remote cabin has a propane fridge dating from the 1930's (Seville) needs occasional 'tweaking', but runs like a top!

They dont have much to wrong, and they don't make em like they used to.

[realist]

I am looking at solar for my cabin I am working on this summer. The problem with refrigerator is the do draw a lot of power. I will have solar but I will have a propane refrigerator. I am also looking at getting a combination electric/propane RV refrigerator for a backup. I also want to have a freezer so I have to figure out just how much solar and batteries I need, and of course how to pay for it all..... The big thing on the larger refrigerator is they also have a nice size freezer so I can have ice in my cocktails.

[Domeguy]

A large problem most people don't consider when thinking about going solar is the "whole package cost". I ran into this a lot when I was starting my company. They seem to think just throw a couple of solar panels on the roof and that's just not the case. When converting an entire home to solar, you not only need the panels, but a inverter, at least two good quality disconnect switches, fuses, fuse panels, lightning arrestor, possibly a new, or second meter, roof racks, wiring, conduit, and a few other things that probably slip my mind. And if you want to add battery backup, then add multiple batterys, a good quality charge controller, more disconnect switches, more wiring and conduit. Then if you have to pay for the install, that can double the price. I'm not saying anyone here has ever said anything to me about how much things cost, but in the end run, things do add up. The cost of just one 200 Ah AGM battery can cost over $350, and you would probably need 3-4, just that alone will be over $1000.
I do however think in the long run, solar power is well worth the investment in the every day world, but in a prepper world, if you want to maintain any of today's lifestyle, it's a necessity, and one that is very high on my to do list.

[Domeguy]

I just found my sheet of calculations I made for Helo with the last set of numbers he had given me. Figuring he was using 4.151 kWh hours per 24 hours, I figured to maintain enough electricity with an added extra for several cloudy days, he needed an array producing 1194 PV watts, or rounded to 1200PVW. I found 4-310W panels at $315 each = $1260. I found an inverter I think for $500, but I didn't write it down, and he would need 7-200Ah batterys at $355 each=$2485. Plus all the extras needed to provide a safe hook-up. But, Cwconnertx thinks Helos numbers were way to high, so hopefully he can get these costs down, and in the long run, a new freezer may just pay for itself.

[cwconnertx]

I just found my sheet of calculations I made for Helo with the last set of numbers he had given me. Figuring he was using 4.151 kWh hours per 24 hours, I figured to maintain enough electricity with an added extra for several cloudy days, he needed an array producing 1194 PV watts, or rounded to 1200PVW. I found 4-310W panels at $315 each = $1260. I found an inverter I think for $500, but I didn't write it down, and he would need 7-200Ah batterys at $355 each=$2485. Plus all the extras needed to provide a safe hook-up. But, Cwconnertx thinks Helos numbers were way to high, so hopefully he can get these costs down, and in the long run, a new freezer may just pay for itself.

What I might add, is that numbers are probably a little high, and what I would suggest is considering oversizing the array and going smaller on the battery bank, here is my thinking

Relative to when most solar guidelines were created, panels are much cheaper compared to batteries. This means that for every dollar spent it goes a lot further on panels than on batteries. Even on a cloudy day the panels will produce some power, so having more reduces the strain on the batteries, enabling you to make due with a smaller battery bank. Use the 110 volt power to keep the batteries from getting discharged when the power works (exercising them once a month or so) and they will last much longer.

There are other things you can do to keep the battery costs down as well. Fill the freezers with some 2 liter bottles of mild salt/sugar water (to reduce freezing point, and its a good rehydration in emergency) to reduce the freezing point and keep the freezers completely full. You can put the freezers on a timer to run only during the day, they should stay frozen if full and kept shut all night.

Best bank for the buck is probably making really sure both freezers are working well and if necessary, replace an ill working older one.

I will stay tuned for measurements of each freezer individually. (I bet domeguy will too)

anything more than 1kw a day is problematic, especially for a smaller unit.

[helomech]

My wife was supposed to hook it to the smaller one today, will ask her when I talk to her.

[cwconnertx]

My wife was supposed to hook it to the smaller one today, will ask her when I talk to her.

Get a 24 or 48 hour period, this should be the worst case time for an outdoor freezer, and it will surely draw more during the day than night. If you can't do an exact time period then a longer time is better than shorter.

Freezers are one of my most important items as I but meat by the case (Costco, USDA PRIME sirlion, under $7 a pound, less than half the cost of the USDA choice shit they sell at the grocery store) and get venison and sometimes other grass fed beef from a client also.

[helomech]

Okay, here are the numbers off of just the smaller older freezer. It has been running for 462 hours. 40.43KWH, 94.5W, 144VA. Those are all the numbers off the meter.

[cwconnertx]

Okay, here are the numbers off of just the smaller older freezer. It has been running for 462 hours. 40.43KWH, 94.5W, 144VA. Those are all the numbers off the meter.

That is more than double the normal usage from a new full size freezer!

That is about 2.1 kw-hr per day or 760+ kw-hr per year, most new models would be labeled for 300-400 kw-hr per year.

Check the new one next, it is possible that there is just a large heat load where they are. It might just benefit from a good cleaning of the coils, checking the gaskets, etc. That stuff can really reduce the load and size of solar system needed.

[helomech]

They are in a really hot shed.

Will hook up the other by itself now.

[bacpacker]

Be sure and check the gaskets and coils. I hadn't gave that any thought, but they will most certainly add to the power usage. Either or both could be a big deal.

[Sniper-T]

There is some good information in this thread