Announcement

Collapse
No announcement yet.

Compounding Question

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Compounding Question

    Hi folks. New guy here, and glad to talk with some new people. My name is Alex.

    I've done a good deal of research trying to learn the best things to do to go solar (on-grid in my case). However, I do have a question that I can't seem to find an answer to. I looked through some of the existing threads and didn't see my question posted anywhere. My apologies for how ignorant this question may seem to some of you who are more electric-savvy.

    My question concerns the compounding of voltage and amperage. I know that watts are volts × amps. I've also figured out that cells run together in a single panel have a compounding effect. For example, a PV cell that produces .5V and 150 mA will have an output of approximately .075 watts. But if you run 36 cells together in a panel, collectively they will produce roughly 100 watts (97.2 watts @ 18V and 5.4A). There are plenty of them for sale on the market.

    But if I string 2 panels together in a series, does the compounding continue? Will I find myself with the collective voltage and amperage of 72 cells, bringing me to 36V and 10.8A for a total of 388.8 watts? Or does the wattage of each panel stand alone and merely add to the one before it rather than compounding the effect, making, in essence, the watts increase from 100 to 200, while the volts go from 18 to 36, and the amps from 5.4 to 10.8?

    In short, if I ran 13 panels in a series, would that give me 1300W, 234V, and 70.2A? Or would it instead result in a compounded wattage of 16.42kW? I think I know the answer (the math sort of shows the absurdity of my question), but I would rather not do something that will get me killed or result in my house burning down. So if someone would be kind enough to give me some bare basics on how voltage, amperage, and wattage combine, compound, or work together, I'd be much appreciative.

    Also (related), a similar question concerns stringing together two or more series of panels. How does the voltage, amperage, and wattage combine? I assume they will combine the same way ... but again, I just want to be safe.

    Thanks in advance for your time in responding.

  • #2
    PV panels when wired in series the voltage adds and the amps remains the same
    When put in parallel the amps add and the voltage remains the same.
    Now the big question. Why on earth are you using 12V 100W battery panels for an on grid application.
    Generally they are the most expensive panels you can buy. Larger like 60 or 72 cell 250W panels are the norm and cost about 1/3 as much as your did.
    NABCEP certified Technical Sales Professional

    [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

    [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

    [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

    Comment


    • #3
      Originally posted by afrazier View Post
      Hi folks. New guy here, and glad to talk with some new people. My name is Alex.

      I've done a good deal of research trying to learn the best things to do to go solar (on-grid in my case). However, I do have a question that I can't seem to find an answer to. I looked through some of the existing threads and didn't see my question posted anywhere. My apologies for how ignorant this question may seem to some of you who are more electric-savvy.

      My question concerns the compounding of voltage and amperage. I know that watts are volts × amps. I've also figured out that cells run together in a single panel have a compounding effect. For example, a PV cell that produces .5V and 150 mA will have an output of approximately .075 watts. But if you run 36 cells together in a panel, collectively they will produce roughly 100 watts (97.2 watts @ 18V and 5.4A). There are plenty of them for sale on the market.

      But if I string 2 panels together in a series, does the compounding continue? Will I find myself with the collective voltage and amperage of 72 cells, bringing me to 36V and 10.8A for a total of 388.8 watts? Or does the wattage of each panel stand alone and merely add to the one before it rather than compounding the effect, making, in essence, the watts increase from 100 to 200, while the volts go from 18 to 36, and the amps from 5.4 to 10.8?

      In short, if I ran 13 panels in a series, would that give me 1300W, 234V, and 70.2A? Or would it instead result in a compounded wattage of 16.42kW? I think I know the answer (the math sort of shows the absurdity of my question), but I would rather not do something that will get me killed or result in my house burning down. So if someone would be kind enough to give me some bare basics on how voltage, amperage, and wattage combine, compound, or work together, I'd be much appreciative.

      Also (related), a similar question concerns stringing together two or more series of panels. How does the voltage, amperage, and wattage combine? I assume they will combine the same way ... but again, I just want to be safe.

      Thanks in advance for your time in responding.
      Watts would remain the same per panel.
      In series volts multiply, amps remain same.
      In parallel amps multiply, volts remain same.

      "in a panel, collectively they will produce roughly 100 watts (97.2 watts @ 18V and 5.4A)"

      two panels in series = 36v / 5.4amp
      two panels in parallel= 18v / 10.8amps

      both the above equal aprx 200watts, 2@ 100w panels

      Comment


      • #4
        Originally posted by Naptown View Post
        PV panels when wired in series the voltage adds and the amps remains the same
        When put in parallel the amps add and the voltage remains the same.
        Now the big question. Why on earth are you using 12V 100W battery panels for an on grid application.
        Generally they are the most expensive panels you can buy. Larger like 60 or 72 cell 250W panels are the norm and cost about 1/3 as much as your did.
        ha! ya beat me to it. Hopefully the low volt and panel wattage were for example only and not what he intends to use for grid tie.

        Comment


        • #5
          Originally posted by FloridaSun View Post
          ha! ya beat me to it. Hopefully the low volt and panel wattage were for example only and not what he intends to use for grid tie.
          Yes, it was just an example. I haven't built or bought anything yet. That's the purpose of the homework. I'm still learning about this stuff. I understand some simple electrical from automotive, but this is a new animal.

          Comment


          • #6
            Originally posted by FloridaSun View Post
            Watts would remain the same per panel.
            In series volts multiply, amps remain same.
            In parallel amps multiply, volts remain same.

            "in a panel, collectively they will produce roughly 100 watts (97.2 watts @ 18V and 5.4A)"

            two panels in series = 36v / 5.4amp
            two panels in parallel= 18v / 10.8amps

            both the above equal aprx 200watts, 2@ 100w panels
            Okay, you slightly lost me. I'm not a hundred percent on the jargin. When you say in parallel, I assume you mean two separate and independent panels that both end at the same source, whereas in a series, the panels connect to each other, and the final panel in the series connects to the end source. Am I understanding you correctly?

            Comment


            • #7
              Originally posted by Naptown View Post
              PV panels when wired in series the voltage adds and the amps remains the same
              When put in parallel the amps add and the voltage remains the same.
              Now the big question. Why on earth are you using 12V 100W battery panels for an on grid application.
              Generally they are the most expensive panels you can buy. Larger like 60 or 72 cell 250W panels are the norm and cost about 1/3 as much as your did.
              I'll gladly build these things 4x8 and have them produce as much as possible. I just have to know what is a) safe, and b) most efficient in terms of output and space. The small panel was just an example of something I've seen in browsing. I'm still new at this.

              Comment


              • #8
                Originally posted by afrazier View Post
                Okay, you slightly lost me. I'm not a hundred percent on the jargin. When you say in parallel, I assume you mean two separate and independent panels that both end at the same source, whereas in a series, the panels connect to each other, and the final panel in the series connects to the end source. Am I understanding you correctly?
                Automotive electricity is defined in the same way ALL lectric is... W=AxV

                Think of batteries....
                Two 12v batteries connected - to +, and then - and + of opposite ends of two batteries (in series) make 24v.
                Two 12v batteries with both - and + terminals connected together (in parallel) still make 12v

                in both cases watts (or Wh) remain the same.
                (using 12v 100Ah batteries for example)
                12v x 100Ah = 1200Wh
                in series, 2 x 12v = 24v x 100Ah = 2400Wh
                parallel, 2 x 100Ah = 200Ah x 12v = 2400Wh

                or; two 100w panels in series = 36v / 5.4amp = 200w
                two 100w panels in parallel= 18v / 10.8amp = 200w

                may take some time to totally wrap your mind around the concept but once it's there you'll know it for life

                BUILDING panels? If you're going grid tie then forget about that. At today's prices you will never have DIY panels at the price and quality of factory built PLUS they would need to be certified to pass permit inspection.

                Comment


                • #9
                  Originally posted by afrazier View Post
                  I'll gladly build these things 4x8 and have them produce as much as possible. I just have to know what is a) safe, and b) most efficient in terms of output and space. The small panel was just an example of something I've seen in browsing. I'm still new at this.
                  Houston we have a problem.
                  If you live in the US and are intending this for a Grid tie you will not be building anything. You will be buying manufactured panels with UL or other NRTL listing and approval. Other than the fact that it would be an illegal installation and would void your insurance in the event of a fire traced to these (And sometimes not even the cause) it will cost you more in the long run to build your own panels than it will to purchase approved quality panels.
                  NABCEP certified Technical Sales Professional

                  [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

                  [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

                  [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

                  Comment


                  • #10
                    What is your end goal? Charging batteries is a very simple setup using Solar since both the battery and the PV panel is D/C. You can also set up led lighting for light, still a D/C system. But if you are going to use the Solar energy to supplement your home energy requirements, you will need to change the D/C from the solar panels into A/C current. This is done by a product called an inverter. The inverters also take care of synchronizing the A/C to that of the grid that your home is using. Remember that in the USA, Alternating Current is 60 cycles per second. These sign waves have to be in sync with each other or they will negate each other and cause all types of issues.

                    When designing a solar system there are a lot of things to take into account. Typically solar panels have been connected in series, like your originally question. Series being the positive from panel one to negative on panel two and so on. That can yield some high voltages and stiff amps if enough panels are connected. Most inverters accept a wide range of voltages, so that is not a problem. The problem with the series connection is if one panel loses its output, say from shade, the whole string is effected. It is kind of like a string of Christmas lights, one goes out, the whole strings goes out

                    One solution is to the series connection is to use micro inverters. With this solution, every solar panel has its own small D/C to A/C inverter. The micro inverters are all connected onto the same trunk cable and you have usable A/C. There are also other advantages to micro inverters. The biggest is that each PV panel can be monitored. And shade on one panel will not shut down the whole system. The down side is that micro inverters are still more expensive than string inverters. I'm personal sold on micro inverters, and feel that the extra cost is justified.

                    Comment


                    • #11
                      Originally posted by Naptown View Post
                      Houston we have a problem.
                      If you live in the US and are intending this for a Grid tie you will not be building anything. You will be buying manufactured panels with UL or other NRTL listing and approval. Other than the fact that it would be an illegal installation and would void your insurance in the event of a fire traced to these (And sometimes not even the cause) it will cost you more in the long run to build your own panels than it will to purchase approved quality panels.
                      It was actually my intention to have the power company hook them up. I didn't realize there was red tape involved, assuming they were built correctly. But I suppose I should have known. You can't flush a toilet nowadays unless it's a government approved flush capacity.

                      Would it be a TOS violation to ask if anyone can recommend some reputable sources for quality panels, brands, etc. at a good price?

                      Comment


                      • #12
                        Originally posted by t5800512 View Post
                        What is your end goal? Charging batteries is a very simple setup using Solar since both the battery and the PV panel is D/C. You can also set up led lighting for light, still a D/C system. But if you are going to use the Solar energy to supplement your home energy requirements, you will need to change the D/C from the solar panels into A/C current. This is done by a product called an inverter. The inverters also take care of synchronizing the A/C to that of the grid that your home is using. Remember that in the USA, Alternating Current is 60 cycles per second. These sign waves have to be in sync with each other or they will negate each other and cause all types of issues.

                        When designing a solar system there are a lot of things to take into account. Typically solar panels have been connected in series, like your originally question. Series being the positive from panel one to negative on panel two and so on. That can yield some high voltages and stiff amps if enough panels are connected. Most inverters accept a wide range of voltages, so that is not a problem. The problem with the series connection is if one panel loses its output, say from shade, the whole string is effected. It is kind of like a string of Christmas lights, one goes out, the whole strings goes out

                        One solution is to the series connection is to use micro inverters. With this solution, every solar panel has its own small D/C to A/C inverter. The micro inverters are all connected onto the same trunk cable and you have usable A/C. There are also other advantages to micro inverters. The biggest is that each PV panel can be monitored. And shade on one panel will not shut down the whole system. The down side is that micro inverters are still more expensive than string inverters. I'm personal sold on micro inverters, and feel that the extra cost is justified.
                        I did read about the microinverters. It sounded like a good idea. Even more so now. I didn't really think about the Christmas light scenario, but that certainly makes sense.

                        Comment


                        • #13
                          Originally posted by afrazier View Post
                          It was actually my intention to have the power company hook them up. I didn't realize there was red tape involved, assuming they were built correctly. But I suppose I should have known. You can't flush a toilet nowadays unless it's a government approved flush capacity.

                          Would it be a TOS violation to ask if anyone can recommend some reputable sources for quality panels, brands, etc. at a good price?
                          Try our sponsor Solar town (link on home page here)
                          Othewise Google is your friend.
                          NABCEP certified Technical Sales Professional

                          [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

                          [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

                          [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

                          Comment


                          • #14
                            Originally posted by afrazier View Post
                            You can't flush a toilet nowadays unless it's a government approved flush capacity.
                            1. Electric systems are a whole lot more involved and potentially dangerous than your toilet.

                            2. Try http://www.solartown.com/store/catalog/solar-panels/
                            [SIGPIC][/SIGPIC]

                            Comment


                            • #15
                              Toilets won't burn your house down, which is usually an insurance issue . A badly done, even with good intentions, solar system on a roof could do that.
                              PowerOne 3.6 x 2, 32 SolarWorld 255W mono

                              Comment

                              Working...
                              X