Questions about Solar Panels - Page 1
Forum section: electronics / beginners

author: SH@RK
author_rank: Contributor
timestamp: November 16, 2012, 05:11:04 pm
content: HiI want to start using solar panels to power some small things as start in my home (mainly to learn)And if it works fine I will get bigger ones so I can power more and moreSo first I want to learn about them and find how much I can use themI already read a lot of topics and watched a lot on youtube about them and how to make themSo I decided to get one and try it1:-How about these ?Grade A , poly crystalline , 6' x 6' , 4.1 W for each piecehttp://www.ebay.com/itm/18-Best-solar-cells-Grade-Multi-Solar-Cell-6x6-High-efficiency-4-1W-each-cell-/271077682301?pt=LH_DefaultDomain_0&hash=item3f1d7d2c7dOrGrade B , 6' x 6' , 3.6 W for each piece (with small minor cosmetic defect)http://www.ebay.com/itm/20pc6-6-3-6W-solar-cells-solar-panel-DIY-high-efficiency-free-shipping-/271095264618?pt=LH_DefaultDomain_0&hash=item3f1e89756aOr2:-Should I go with the full packages (panels + flux + diodes + tabbing wire + bus wire)http://www.ebay.com/itm/6x6-High-efficiency-solar-cells-3-6W-piece-cell-kit-DIY-panel-fountain-toy-/281016712469?pt=LH_DefaultDomain_0&var=&hash=item8713e5d8bchttp://www.ebay.com/itm/80-3x6-POLY-CELLS-2-WT-EA-TAB-BUSS-WIRE-FLUX-PEN-J-BOX-SOLAR-PANEL-DIY-KIT-/170903482713?pt=LH_DefaultDomain_0&hash=item27caa43159I am interested in the last link (free shipping to KSA)I found in eBay they say "B Grade with small minor cosmetic defect"3:-What do they mean by "small minor cosmetic defect" ?The products in the pictures looks good for me4:-And for the front face for the ending frame is glass the best thing to use ?5:-So any suggestions where to start and buy ?6:-Should I buy the best or start with B grade ?7:-Do u think buying the pieces and making my solar panel by my self is cheaper ?8:-Do I have to use battery bank or I can use solar power directly (small appliances ) ?9:-what about using solar energy at home , the idea itself , Is it good or wasting money ?Thanks

author: Lightages
author_rank: Unknown
timestamp: November 16, 2012, 05:28:06 pm
content: First, forget everything before question 7. Making your own panels might be a nice hobby, but it does not pay off in the long run. Manufactured panels can be purchased for under $1USD per watt now. You can buy a good quality 240W panel for $221USD. It will be weather proof, guaranteed, and more durable than almost anything you can build yourself at anywhere near the same price.You can use the solar panel to charge directly, but you need to use a charge controller in any case. It is better to have some battery capacity for stability in the power output and for being able to have power to do other things, and to store the power from the panels when you are not charging a device directly.If you are in a very sunny area and electricity is unreliable or very expensive, then solar power is a viable alternative. If you have normal not too expensive electrical power from the grid available, solar power is never cheaper.

author: poptones
author_rank: Frequent Contributor
timestamp: November 16, 2012, 10:29:46 pm
content: This is why many people hate China...Can I offer this mode of thinking? "Solar panels" can be just about anything. People think of "solar energy" as those black roof panels that make electricity, but when you consider most of the energy use in a home for several months will be for heating, it's amazing how many still don't think of "solar heating" as something that's usable. My own home is solar heated for much of the year - right now it is, for example, because the sun is out and it's closed up. What I want to do is add a collector and closet on one side so I can store heat to be released at night over the winter. That's active solar but doesn't entail electricity. Look at the stuff nick pine is doing with solar closets. PV cells can take decades to pay off, a solar closet can pay itself off in two.http://www.ece.villanova.edu/~nick/solar/solar.htmlhttps://sites.google.com/a/southsidecomfort.com/natural-comfort-by-design/solar-closet-byCosmetic imperfections can lead to inefficiencies in PV cells. So can heat, which is trapped by glass and especially by glass that is not UV rated. So if you get glass that is not UV transparent then it can help heat the cells through radiation AND trap the heat. I don't know that cheap solar panels are going to be made with quality glass, or with utmost efficiency in mind.Also, you might think about concentrated solar. Regular PV panels don't do particularly well with efficiency. With concentrated solar you can get over 30% efficiency.

author: G7PSK
author_rank: Super Contributor
timestamp: November 16, 2012, 11:11:54 pm
content: I wondered what you meant by solar closet for a moment then I realized you were talking about conservatory's. Some thing that has been around since Victorian times.

author: poptones
author_rank: Frequent Contributor
timestamp: November 16, 2012, 11:27:30 pm
content: No, it isn't. Conservatories are big open spaces. Solar closets are just what they sound like - closed, small areas designed for one thing: to hold heat. Conservatories are lousy at keeping heat because they're covered with glass. They're too hot in the summer and too cold in the winter. Solar closets are made to be heat reserves. That's all they do. They're not living spaces, they're not greenhouses.

author: G7PSK
author_rank: Super Contributor
timestamp: November 19, 2012, 06:12:33 pm
content: I googled solar closet and found this. It looks like a conservatory to me. also I don't know what standards are used in the US but here in the UK conservatory's are double or triple glazed with heat retaining glass and even in winter get hot in the sun.

author: M. András
author_rank: Super Contributor
timestamp: November 19, 2012, 06:43:43 pm
content: Quote from: Lightages on November 16, 2012, 05:28:06 pmhmm i would be glad to get 1 for that price here in hungary. checked a few sites for solar panels and they go minimum the double of that price you mentioned, calculated back from our currency to usd

author: poptones
author_rank: Frequent Contributor
timestamp: November 19, 2012, 06:47:17 pm
content: conservatory's are double or triple glazed with heat retaining glass and even in winter get hot in the sunUh huh. And shed it all night long because your thermal mass has terrible insulation around it. It's hard to control temp during the day AND at night and it costs a fortune because of all that expensive glass.That's NOT a solar closet, it's a conservatory or greenhouse or atrium or whatever you want to call it OTHER than a solar closet. How did you manage to google solar closet, find this image, and not find the 100 other images that DO show what a solar closet is? This is the first image that comes up in the search.As you can clearly see it is NOT an atrium or even a livable space. It is designed to do one thing: collect and store heat. It's not a place for your plants or a place to entertain, it's a mass attached to your house that is designed to store heat year around and (most important) to release it back into your living space in controlled fashion.

author: Zero999
author_rank: Super Contributor
timestamp: November 20, 2012, 01:20:22 pm
content: I don't think any one has noted the original poster's location is Saudi Arabia where it's very sunny so very little energy will be used for heating and lots will be used for cooling.

author: SH@RK
author_rank: Contributor
timestamp: November 20, 2012, 03:05:59 pm
content: Quote from: Lightages on November 16, 2012, 05:28:06 pmThank youFor my home monthly electricity usage ---Each month almost 7500 KWh7500 KWh costs == 800 SR =~ 213 $This is how it is calculated (calculate each level separately then sum the total)So do u think the solar energy will be good thing to make this cost (almost ) disappearI will start looking for manufactured panels and see the prices if I can get something cheap and working goodQuote from: Hero999 on November 20, 2012, 01:20:22 pmYeah we do not use heating systems (I do not have one) . Mainly cooling systems (day and night)In summer, temperature reaches 51C' at noon (most of the time between 41 - 46 C' )Thanks

author: Lightages
author_rank: Unknown
timestamp: November 20, 2012, 05:23:23 pm
content: Quote from: SH@RK on November 20, 2012, 03:05:59 pmReally? that much? Wow! I use 20KWh per day, not 250KWh per day!Quote from: SH@RK on November 20, 2012, 03:05:59 pmI think you miscalculated here. From your chart and consumption I see the cost in SR as 2,100. And the current conversion as I see it on the web is more like $560USD per month.So, to answer your question I need to know; what is your peak draw or consumption? what is land area you have for panels? is your main consumption only during the day or is it all day and night? If the main consumption is day only, what is your night time consumption.With my 20KWh daily consumption, I have a system with around 3200W of panels and 750AH at 48V worth of batteries. My system cost around $25,000 USD. If you need a system 12 times bigger.......I am really finding it hard to believe your monthly consumption is 7500KWh.

author: ejeffrey
author_rank: Super Contributor
timestamp: November 20, 2012, 05:37:58 pm
content: Quote from: Lightages on November 20, 2012, 05:23:23 pmThat is a progressive rate. So he pays .05/kWhr for the first 2000, 0.10 for the next 1000 kWhr and so forth. That works out to about the 800 he quotes. I get 980In any case, 7500 kWhr/month is huge for a residential use -- that is 10 kilowatt 24/7. Do you have a manufacturing plant or data center running in your home, or run heavy farm equipment? If that is your average, what is your peak load? That will affect what type of inverters/batteries you need.

author: Lightages
author_rank: Unknown
timestamp: November 20, 2012, 05:44:12 pm
content: Quote from: ejeffrey on November 20, 2012, 05:37:58 pmDOH! Of course!

author: poptones
author_rank: Frequent Contributor
timestamp: November 20, 2012, 06:35:43 pm
content: It sounds lie what you really need is to get 1500kw/h off your bill, not necessarily ALL of it (which I think is impractical). If you reduce your usage by 1500kwh you would cut your bill nearly in half because of your progressive billing method. That's about 20% of your power usage.So now I understand you are in Saudi Arabia. So how expensive is water there? I live in Tucson AZ which has similar weather at least a large part of the year. Summer temps here routinely exceed 110 degrees, often it gets to about 120, and I almost never use my air conditioner because I have a swamp cooler. Have you considered that? Last summer my heat and water combined never went over 100 bucks a month. It doesn't seem impractical at all to consider reducing your power bill 20% through the use of a swamp cooler, but of course that depends on cheap water.

author: Lightages
author_rank: Unknown
timestamp: November 20, 2012, 06:45:26 pm
content: Yes, reduction is always the best alternative. I just still can't understand using 250KWh per day.

author: SeanB
author_rank: Super Contributor
timestamp: November 21, 2012, 04:27:46 am
content: Aircons on in all rooms 24/7 will do that, especially in a poorly insulated building and with windows/doors left open for significant periods and with them turned down to as cold as possible so the compressors run 24/7. 6 24000BTU units will do that easily. Each draws around 15A when running, so 3kW.