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    Solar panel project problems Comments?-gctid390090

    I said I would post when I continued with my Solar panel project.

    To review, I purchased two 100 watt, 20 volt solar panels with a rating of 5.86 amps each and a PWM controller.

    A couple of weeks ago I installed the two panels on the back roof of my 3288. They are not in full sun all day but for the most part. The panels I got were high efficiency with shadow and diode protection.

    The panels warned not to connect under load. Considering solar panels put out the second light hits them I really don't know how you do that but I was careful connecting the panels to the controller before connecting the battery and included a switch to allow for disconnecting the battery when the panels were disconnected for any reason.

    I can't say the results were as expected.

    Under no load the panels put out 19.7 volt as expected. The controller regulates this down to 14.5 volt, again as expected. Once connected to the battery the voltages drops to battery voltage, again as expected.

    Now comes the problems,

    Even under full sunlight the most I get out is around 3 amps. This is will below the maximum output of over 10 amps. I checked the diodes in the panel junction box and all seems to be working. The whole system is very simple so right now I'm not sure if the panels are faulty or not as I have no experience with panels.

    I'm open to suggestions.

    #2
    lolar3288 wrote:
    Even under full sunlight the most I get out is around 3 amps. This is will below the maximum output of over 10 amps. I checked the diodes in the panel junction box and all seems to be working. The whole system is very simple so right now I'm not sure if the panels are faulty or not as I have no experience with panels.

    I'm open to suggestions.
    Do you measure the battery charge current? If so it depends on how discharged the battery is. If it's close to fully charged the controller will regulate it down to prevent gassing.

    Comment


      #3
      Rule of thumb your panels should be tiltd at the angle of you latitude for maximum efficiency, So in you case around 43 degs. If they are lying flat your are loosing a lot of efficiency.
      John McLellan White Rock BC
      "Halifax Jack"
      1999 2855 383 stroker BII
      MMSI 316004337

      Comment


        #4
        kjs wrote:
        Do you measure the battery charge current? If so it depends on how discharged the battery is. If it's close to fully charged the controller will regulate it down to prevent gassing.
        I measured the current the panels were producing with a load on the batteries so it's more of a difference with and without panel current.

        Comment


          #5
          Couple of things to look at:

          1. Do you have the correct gauge of wiring between the panel and your controller? http://www.freesunpower.com/wire_calc.php -- for a 3% loss of power you'll want to have 9 gauge wire or larger.

          2. Have you turned-off/isolated all items that draw DC power? I made that mistake recently with my install -- TriMetric meter was only showing +2.5A but I didn't realize there were DC items currently running that were drawing power so what I saw was the combination of In and Out.

          3. Are your batteries already fully charged? Might want to consider running them down for a while (e.g. turn your fridge on full blast for an hour or more) and then measure the total amps produced.

          4. What are you using to measure the charging capacity? I believe you have a monitor. Is it operating properly? Have you confirmed your readings with a multi-meter to be certain?

          5. What is the make/model of your charge controller? Is it positioned next to your batteries?

          6. What did your manufacturer indicate re panels having "shadow" protection? If your panels are in shadow -- even a bit, you are going to experience a massive drop in power (along the lines of what you are seeing). Usually the manufacturer means they have installed blocking diodes -- such that if there is a shadow across the panel, those cells within the shadow are turned off rather than absorb energy from the cells producing power. That's a common design for all panels -- without blocking diodes, there is a risk of fire.

          If we can't help you pinpoint any performance issues here, I'd recommend posting your system layout and manufacturer specs here: http://www.wind-sun.com/ForumVB/foru...attery-Systems -- these guys are very helpful.
          Terry
          1999 Bayliner 3388
          Twin Cummins 4BTA
          Fisherman, Cruiser, Boaticus-enthusiasticus-maximus
          Member Royal Victoria Yacht Club

          Comment


            #6
            A similar thread on the solar forum: http://www.wind-sun.com/ForumVB/show...rs-I-m-getting
            Terry
            1999 Bayliner 3388
            Twin Cummins 4BTA
            Fisherman, Cruiser, Boaticus-enthusiasticus-maximus
            Member Royal Victoria Yacht Club

            Comment


              #7
              TenMile wrote:
              Couple of things to look at:

              1. Do you have the correct gauge of wiring between the panel and your controller? http://www.freesunpower.com/wire_calc.php -- for a 3% loss of power you'll want to have 9 gauge wire or larger.

              The whole system is wired with #8 AWG wire.

              2. Have you turned-off/isolated all items that draw DC power? I made that mistake recently with my install -- TriMetric meter was only showing +2.5A but I didn't realize there were DC items currently running that were drawing power so what I saw was the combination of In and Out.

              Yes I did...my miminum power consumption is around 2 amps without the frig

              3. Are your batteries already fully charged? Might want to consider running them down for a while (e.g. turn your fridge on full blast for an hour or more) and then measure the total amps produced.

              Yes I thought of this so I ran the batteries down over night

              4. What are you using to measure the charging capacity? I believe you have a monitor. Is it operating properly? Have you confirmed your readings with a multi-meter to be certain?

              I have an digital panel amp meter and volt meter on the house system. The shunt is installed on the negative house bank.



              5. What is the make/model of your charge controller? Is it positioned next to your batteries?

              I can't remember the make (sun something) but it is within 6 feet of the batteries and wired with #8 wire

              6. What did your manufacturer indicate re panels having "shadow" protection? If your panels are in shadow -- even a bit, you are going to experience a massive drop in power (along the lines of what you are seeing). Usually the manufacturer means they have installed blocking diodes -- such that if there is a shadow across the panel, those cells within the shadow are turned off rather than absorb energy from the cells producing power. That's a common design for all panels -- without blocking diodes, there is a risk of fire.

              THe manufacture claimed the panels are shadow protected, I know there are three high current diodes in the connection box of each panel but they are wired in series across the line so I suspect they are reverse voltage protection??

              If we can't help you pinpoint any performance issues here, I'd recommend posting your system layout and manufacturer specs here: http://www.wind-sun.com/ForumVB/foru...attery-Systems -- these guys are very helpful.

              I will have a look at this site
              I have tested under several conditions like full open to sun and under shadow.....not much seems to change. I realise my lack of experience with solar energy probably is a factor in my results so I appreciate the help.

              Comment


                #8
                A quick note.

                If it's a Sunsaver controller you have -- there is a specific order for connecting the battery and panel (at least that's the way mine works). The Battery and Panel terminals are labelled 1, 2, 3, 4 and indicate this is the order of installation. I believe you connect the Neg and Pos from the battery to the controller first, then the Neg and Pos from the panel. If you don't, at least with the model I have, the controller doesn't operate properly.
                Terry
                1999 Bayliner 3388
                Twin Cummins 4BTA
                Fisherman, Cruiser, Boaticus-enthusiasticus-maximus
                Member Royal Victoria Yacht Club

                Comment


                  #9
                  There are a number of different ratings for a solar panel. One is dead short amperage which will give the highest amp reading, but zero watts. Another is open circuit voltage which gives maximum volts, but zero amps (and so zero watts).

                  Max efficiency is achieved at the "knee" of the volts vs amps curve. Here the product of volts times amps gives you the panel rating in watts.

                  So far so good.

                  In reality, the batteries hold the panle voltage down below that value which gives the maximum power,; typically around 17 volts or so for a panel intended to charge 12 volt batteries. (After about 14 volts, your 12 volt battery will begin to boil) My experience is that you will achieve about 75% (max) of panel rated power because of the battery limiting voltage and losses in the charge controller.

                  While this doesn't explain your 3 amp output, it should help explain solar charging a little.
                  2007 Discovery 246
                  300mpi BIII
                  Welcome island Lake Superior

                  Comment


                    #10
                    Can you post a photo of your panel installation?

                    Based upon inefficiencies of the panels, wiring etc... your power goal should probably be about 8Amps or thereabouts. Amorphous panels are somewhat less efficient than mono-silicon panels (but not what you're seeing).

                    I wasn't sure based upon your measurements if your ~2Amps was production from the panel alone or also included the draw from your boat (also ~2Amps). So we're either trying to find 50% or 75% of your power loss.

                    Your wiring sounds like it's great. Positioning of the controller is great. Check the controller's hook-up sequence as above. Other than that, assuming all the measurements are correct then the issue has to be panel related. Either the panel is in partial shadow from the boat structure, an antenna or adjacent sailboat rig etc..., or the panel is not oriented to face the sun (the ~42 degree orientation advice above is a year round rule of thumb -- given we are approaching the longest day of the year where the sun is at it's highest -- your panel should be tilted at about 16 degrees facing sough given your location in order to maximize it's performance).
                    Terry
                    1999 Bayliner 3388
                    Twin Cummins 4BTA
                    Fisherman, Cruiser, Boaticus-enthusiasticus-maximus
                    Member Royal Victoria Yacht Club

                    Comment


                      #11
                      What I would do is bypass the regulator for now. Hook the panels directly into the battery, through an ammeter and see what you get for amperage. I always like to go from the simplist system towards the complex, that way you can prove things all the way.

                      With the controller back in the circuit, turn a bunch of stuff on to get the voltage down to the low 12's. The reg should turn fully on and you should see almost the same amperage flowing (a little less due to the reg losses). Otherwise the reg is a pos.

                      Some controllers are just poor designs too. I'm not familiar with your product, but I bought a cheap 15A 'regulator'...it was junk. I ended up getting rid of the reg and used a .... switch. I just turned it on when I wanted juice. Far from the optimal solution, but it was a stopgap for when I went cruising shortly after the install.

                      I made my own reg. after that, which is a maximum power point regulator until the battery charges near full, then it becomes a regulator (battery charger algorithm) until the batteries are topped off.

                      Chay

                      Comment


                        #12
                        One more thing...the guage of the wire is a bunch of BS.

                        For an inverter 12V feed, yes, quite important.

                        For a 8 amp array....run #12 or #14 and save your money!!!!

                        A little math:

                        12V, 8A = 96W

                        Let's say we loose 1/2 volt: 92W

                        This is a 4.1% loss in power (big deal).

                        You could run 40 feet of #12 to achieve this (Divide by 2 because of pos and neg run), so 20', which is fine for most installs. As the voltage goes up the power loss becomes smaller (At 14V, the power loss is 3.6%).

                        Chay

                        Comment


                          #13
                          TenMile wrote:
                          Can you post a photo of your panel installation?

                          Based upon inefficiencies of the panels, wiring etc... your power goal should probably be about 8Amps or thereabouts. Amorphous panels are somewhat less efficient than mono-silicon panels (but not what you're seeing).

                          I wasn't sure based upon your measurements if your ~2Amps was production from the panel alone or also included the draw from your boat (also ~2Amps). So we're either trying to find 50% or 75% of your power loss.

                          Your wiring sounds like it's great. Positioning of the controller is great. Check the controller's hook-up sequence as above. Other than that, assuming all the measurements are correct then the issue has to be panel related. Either the panel is in partial shadow from the boat structure, an antenna or adjacent sailboat rig etc..., or the panel is not oriented to face the sun (the ~42 degree orientation advice above is a year round rule of thumb -- given we are approaching the longest day of the year where the sun is at it's highest -- your panel should be tilted at about 16 degrees facing sough given your location in order to maximize it's performance).
                          The controller is a sun sc20B1224. It seems to reflect the readings I took from other instruments but there is no order of hookup. The panels have a warning tag on..do not connect under load so I connected the panels to the controller then the batteries to the controller. Right now I'm at anchor with all my computer stuff running and the frig. Full load is 10.9 amps. The panels are flat on the top and in full afternoon sun light and the output is still between 2 and 3 amps. I have never seen it any higher. There is no way I can tilt the panels but I would swear one is not working at all.

                          Comment


                            #14
                            Sounds like you need to start breaking things apart to test. Remove the controller and test again under load. Daisy chain your panels (to make them 200w, 10A) and hook them directly to your battery/shunt.
                            Terry
                            1999 Bayliner 3388
                            Twin Cummins 4BTA
                            Fisherman, Cruiser, Boaticus-enthusiasticus-maximus
                            Member Royal Victoria Yacht Club

                            Comment


                              #15
                              Just to show you that achieving close to 100% capacity is completely possible here is a shot of my Trimetric monitor today. Panel is in full sun. Components as follows:Panel: 85W BP Solar rated at 4.86 AmpsCharge Controller: Morningstar Sunsaver-10 PWMBatteries: 2 x Trojan T105 6V -- 225AhPanel sits on my awning and faces SW when in my slip. It's tilted at roughly 30 degrees and gets full sun from about 1pm onward until sunset.

                              [img]/media/kunena/attachments/vb/695174=28745-photo.JPG[/img]Note that my inverter is off. My boat at rest draws about .5A (Mercathode mainly plus ACR). So at 4.5A you see is actually closer to 5A if you take into consideration the draw of the existing components.

                              [img]/media/kunena/attachments/vb/695174=28746-photo.JPG[/img]85W panel mounted.
                              Terry
                              1999 Bayliner 3388
                              Twin Cummins 4BTA
                              Fisherman, Cruiser, Boaticus-enthusiasticus-maximus
                              Member Royal Victoria Yacht Club

                              Comment

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