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  • Help me choose between a limited few Solar Panals

    Sorry for my empty post, had to make sure that i could post before i decided to write the deleted post all over again.

    I live in china, solar panels here are more expensive than i first thought. Anyway i want to try to make a system that can charge my A/C which eats 2000 watts.

    From chinas ebay (taobaoDOTcom) i only find three products which have good reviews, and are affordable. I hope someone could help me decide which on to choose. all the panels here are high in voltage and low in watt output. Most have a ratio of 4 to 1.

    Here are the specs of the panels i am considering (they will be connect to make a big panel, and it will be used with a battery, inverter and controller).
    (1) 0.5w 1.5v 2$, (2) 2w 5v 5$, (3) 1w 5v 2,5$

    Could i make a panel that consisted of a combination of all these three?

    I am leaning towards nr 1. That panel is flexible so i will be able to bring it back home in 2 years.
    How many of that panel do i need run my A/C? And anyone know why all the panels here have bigger voltage than watt outout?
    Last edited by Mike90250; 02-28-2014, 06:41 PM.

  • #2
    Originally posted by oollff View Post
    Sorry for my empty post, had to make sure that i could post before i decided to write the deleted post all over again.

    I live in china, solar panels here are more expensive than i first thought. Anyway i want to try to make a system that can charge my A/C which eats 2000 watts.

    From chinas ebay (taobao.com) i only find three products which have good reviews, and are affordable. I hope someone could help me decide which on to choose. all the panels here are high in voltage and low in watt output. Most have a ratio of 4 to 1.

    Here are the specs of the panels i am considering (they will be connect to make a big panel, and it will be used with a battery, inverter and controller).
    (1) 0.5w 1.5v 2$, (2) 2w 5v 5$, (3) 1w 5v 2,5$

    Could i make a panel that consisted of a combination of all these three?

    I am leaning towards nr 1. That panel is flexible so i will be able to bring it back home in 2 years.
    How many of that panel do i need run my A/C? And anyone know why all the panels here have bigger voltage than watt outout?
    Welcome to Solar Panel Talk, ooliff!

    It is impossible to build a system to deliver that range of power by making your own panels from cells instead of buying completed panels.

    The cells you get will not be first quality and you will not be able to make the panels safe and weatherproof because you will not have access to the necessary equipment or designs. They will not last.
    The panels that you describe use a small number of cells (each cell will contribute roughly .5 volts) and cost much more per watt of output than a larger panel (in the 200-300 watt range)

    The reason that the panels have a bigger voltage than watt output is that they deliver less than 1 amp of current. A simple application of Ohm's Law.

    To get higher current, the individual cells that make up the panel will typically be in the 3" x 6" or 6" x 6" size range.

    In the US, using panels typically imported from China, you will see prices as low as $1 per watt in the larger sizes.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

    Comment


    • #3
      Originally posted by inetdog View Post
      Welcome to Solar Panel Talk, ooliff!

      It is impossible to build a system to deliver that range of power by making your own panels from cells instead of buying completed panels.

      The cells you get will not be first quality and you will not be able to make the panels safe and weatherproof because you will not have access to the necessary equipment or designs. They will not last.
      The panels that you describe use a small number of cells (each cell will contribute roughly .5 volts) and cost much more per watt of output than a larger panel (in the 200-300 watt range)

      The reason that the panels have a bigger voltage than watt output is that they deliver less than 1 amp of current. A simple application of Ohm's Law.

      To get higher current, the individual cells that make up the panel will typically be in the 3" x 6" or 6" x 6" size range.

      In the US, using panels typically imported from China, you will see prices as low as $1 per watt in the larger sizes.
      Thanks a lot for your reply.
      I am not thinking about making a panel from cells, i am thinking about connecting small panels to make a bigger one. The panels i am looking at are already weatherproof, i was thinking about something similar to what this guy did. And how could you say that it is "impossible" to build such a system, even if it was from cells. There are many people who have done it, so surly it is not impossible!

      "To get higher current, the individual cells that make up the panel will typically be in the 3" x 6" or 6" x 6" size range. "
      This seems interesting . Would this also be possible to do with panels? For example if i put panels with the capacity (1.5v * 36mA = 0.54W). And i wire 12 of them to a group, each group would get 18v. And if i have 12 groups in parallel i would get an output of 0.54 * 144 = 77w (12x12)... If i changed formation could i get a higher watt output somehow? And would the above configuration have a total of 216 voltage or 18v? Hmm, how much watts would a 6x18 formation produce?

      Two 80w panels that get 8 hours of good sun would charge a battery with only 1280 watt a day. Is it right to think this way? So if i charge for 2 days, i can only run the A/C for a little over an hour. Am i doing the math correct?

      These are the specific panels i am looking at (they seem expensive for what you get, right?):

      http://item.taobao.com/item.htm?spm=...p27053736d5505

      http://item.taobao.com/item.htm?id=1....1.17.8.qzucEc

      Comment


      • #4
        Originally posted by oollff View Post
        And how could you say that it is "impossible" to build such a system, even if it was from cells. There are many people who have done it, so surly it is not impossible!
        OK - Inetdog made a mistake - he should have qualified the statement by saying "in a safe and sensible manner".

        Nothing that guy has built would ever get by an inspection of any type.
        [SIGPIC][/SIGPIC]

        Comment


        • #5
          why all the pessimism? Arent most people who search about solar panels online DIY fanatics? I have made a lot of DIY projects in the past, and i always ask for input on forums related to those areas. Why not give helpful feedback and in a footnote end with that it is very difficult, and possibly dangerous to do it yourself.

          Comment


          • #6
            Originally posted by oollff View Post
            why all the pessimism? Arent most people who search about solar panels online DIY fanatics? I have made a lot of DIY projects in the past, and i always ask for input on forums related to those areas. Why not give helpful feedback and in a footnote end with that it is very difficult, and possibly dangerous to do it yourself.
            No pessimisim involved sorry to say.

            Very few people want to build their own panels - very, very few.

            Home made panels will offer no assurance of not having problems - not smart to have them connected to whatever you may value.

            Panels are so cheap today that we really encourage people to go that route.

            Shade tree stuff is fine for one's own enjoyment - we will not allow anything illegal or questionable to be posted.
            [SIGPIC][/SIGPIC]

            Comment


            • #7
              Originally posted by russ View Post
              No pessimisim involved sorry to say.

              Very few people want to build their own panels - very, very few.

              Home made panels will offer no assurance of not having problems - not smart to have them connected to whatever you may value.

              Panels are so cheap today that we really encourage people to go that route.

              Shade tree stuff is fine for one's own enjoyment - we will not allow anything illegal or questionable to be posted.
              Is it illegal or questionable to ask for advices in ones journey to build a solar panel system? Asking people with more experience is done in every field, every day. Imaging what society would be like if people always answered questions with "it cannot be done", "don't do it yourself", "doing it yourself will lead to certain failure"! I feel for children with such parents.

              I am not doing it for the price, it can even be more expensive for all i care. What i want is knowledge and experience!

              Anyone have any constructive criticism, or could help me with any of my questions? I would highly appreciate it. Quite funny that two people that seem very knowledgeable in the area, haven't really posted some type of answer to any of my questions.

              Comment


              • #8
                Originally posted by oollff View Post
                if people always answered questions with "it cannot be done", "don't do it yourself", "doing it yourself will lead to certain failure"! I feel for children with such parents. Cut the BS - I feel sorry for people that make that statement.

                I am not doing it for the price, it can even be more expensive for all i care. What i want is knowledge and experience! Your right - as I noted

                Anyone have any constructive criticism, or could help me with any of my questions? I would highly appreciate it. Quite funny that two people that seem very knowledgeable in the area, haven't really posted some type of answer to any of my questions.

                Post on a public forum then cry?
                [SIGPIC][/SIGPIC]

                Comment


                • #9
                  I am sorry, it was wrong of me to make accusations and be rude. I always get carried away when people say that one should not try to do something themselves. Especially when one is genuinely interested in learning all about something, it is in the beginning that motivation is the most fragile.

                  May be you are right, this isn't the forum for these types of questions :/. I decided to become part of this forum because it is active and people seem knowledgeable and interesting in something i want to learn more about.

                  Edit//
                  I now see that there is a proper sub forum for this thread. Could you please move it to the "DIY solar panels" forum.

                  Comment


                  • #10
                    Originally posted by oollff View Post
                    Is it illegal or questionable to ask for advices in ones journey to build a solar panel system? Asking people with more experience is done in every field, every day. Imaging what society would be like if people always answered questions with "it cannot be done", "don't do it yourself", "doing it yourself will lead to certain failure"! I feel for children with such parents.

                    I am not doing it for the price, it can even be more expensive for all i care. What i want is knowledge and experience!

                    Anyone have any constructive criticism, or could help me with any of my questions? I would highly appreciate it. Quite funny that two people that seem very knowledgeable in the area, haven't really posted some type of answer to any of my questions.
                    Given the three choices you offer, #2 and #3 both give you a cost of $2.5 per watt. So I would go with whichever takes up the least space or fits together best.
                    To mix multiple types of cells or panels into a larger array will require that either the voltages are compatible so that you can put them in parallel or that the currents are compatible so that you can put them in series. Unless you can only get a limited number of each, I do not see any reason to try to combine more than one type.

                    Google Arthur C. Clarke's three laws of technology, or just follow this link to Wikipedia.

                    On the other hand, the cautions you get here are not just theoretical arguments, they are the distillation of extensive experience, both first and second hand.

                    There are a couple of very active members on this forum who have a lot of fun with DIY, knowing that they are not saving money or have very specialized uses where ready-made panels are not available in the size or shape they want. And, yes you will get a lot better responses if the thread can be moved to the other sub forum. Unfortunately I do not know how to do that yet.
                    SunnyBoy 3000 US, 18 BP Solar 175B panels.

                    Comment


                    • #11
                      Originally posted by oollff View Post
                      ..... Could you please move it to the "DIY solar panels" forum.
                      Done
                      Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                      || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                      || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                      solar: http://tinyurl.com/LMR-Solar
                      gen: http://tinyurl.com/LMR-Lister

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