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  • Can I Combine These Trackers?

    I have two separate trackers with different solar panels. I now need to "combine" both trackers into one system, with a common charge controller, battery bank, and inverter. Tracker #1 has 8 Arco 16-2000 panels with specs of 33 watts, open ckt 21.6v, rated at 16v. System #2 has 4 siemens SR-90s with specs of 90 watts, open ckt 20v, and rated at 17v. Since they are of very similar voltages, can I combine them without any significant problems? Any feedback would be greatly appreciated.

  • #2
    I would suggest a separate MPPT controller for each array.

    You did not say what voltage your arrays are wired for, or your battery voltage.

    Parallel panels, need fuses installed to be safe. Series panels don't need fuses.

    2 fairly equal arrays, can be paralleled with out a fuse, but add a 3rd, and you need fuses on all.
    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

    Comment


    • #3
      Originally posted by Mike90250 View Post
      I would suggest a separate MPPT controller for each array.

      You did not say what voltage your arrays are wired for, or your battery voltage.

      Parallel panels, need fuses installed to be safe. Series panels don't need fuses.

      2 fairly equal arrays, can be paralleled with out a fuse, but add a 3rd, and you need fuses on all.
      Thanks, Mike. My two arrays are wired for 12 volts, that is, they are wired in parallel (minus to minus, plus to plus, adding current with voltage remaining the same), connected into a 12 volt battery bank. The smaller arco array is 33w X 8 panels= 264 watts////and the Siemens array is 90w X 4 panels+ 360 watts. Now when you say "2 fairly equal arrays can be paralleled without a fuse", are you referring to the "wattage"? So are mine "fairly equal"? Thanks, Joe

      Comment


      • #4
        OK, now that I know how (I think everything is in parallel) your arrays are wired, and system voltage,
        I have 2 different paths to suggest.

        Leave it all in parallel, 16.5V and use PWM controllers.

        Tracker #1 has 8 Arco 16-2000 panels with specs of 33 watts, open ckt 21.6v, rated at 16v.
        264w, 16A
        System #2 has 4 siemens SR-90s with specs of 90 watts, open ckt 20v, and rated at 17v
        360w 21A

        Poor choice, tracker 1 will fall below battery charging voltage on anything other than cool or windy days, as PV panels heat up, their output voltage drops. 16V is barely enough to generate charge on low batteries, and will do little for nearly full batteries.

        When you say "tracker" you have a system that follows the sun from sunrise to sunset?

        This "All Parallel" system will also need to have 12 fuses (one at each panel) and several combiner boxes to be safe.

        Also, each array will need large gauge wire (about #10 & #8 awg, respectively) going to a large, 40A PWM charge controller.

        --- OR ---

        the other way is to split each array to a series/parallel wiring, and 2 different MPPT controllers.

        Tracker #1 has 8 Arco 16-2000 panels with specs of 33 watts, open ckt 21.6v, rated at 16v.
        264w
        4 panels in series = 64V, parallel 2 strings of 4 = 4A for the wire run to the controller, 14ga wire fine

        System #2 has 4 siemens SR-90s with specs of 90 watts, open ckt 20v, and rated at 17v
        360w
        4 panels in series = 68V, 1 string of 4 = 5A for the wire run to the controller, 12ga wire fine

        Both are well below the 150VDC limit for the professional MPPT controllers. Depending on the wire distance, you may save enough on the wiring to pay for the 2 MPPT controllers. Rogue and Midnight make some rugged entry level MPPT controllers. The Rogue, you may have to check it's input DCv limit.
        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

        Comment


        • #5
          Originally posted by Mike90250 View Post
          OK, now that I know how (I think everything is in parallel) your arrays are wired, and system voltage,
          I have 2 different paths to suggest.

          Leave it all in parallel, 16.5V and use PWM controllers.

          264w, 16A
          360w 21A

          Poor choice, tracker 1 will fall below battery charging voltage on anything other than cool or windy days, as PV panels heat up, their output voltage drops. 16V is barely enough to generate charge on low batteries, and will do little for nearly full batteries.

          When you say "tracker" you have a system that follows the sun from sunrise to sunset?

          This "All Parallel" system will also need to have 12 fuses (one at each panel) and several combiner boxes to be safe.

          Also, each array will need large gauge wire (about #10 & #8 awg, respectively) going to a large, 40A PWM charge controller.

          --- OR ---

          the other way is to split each array to a series/parallel wiring, and 2 different MPPT controllers.

          264w
          4 panels in series = 64V, parallel 2 strings of 4 = 4A for the wire run to the controller, 14ga wire fine

          360w
          4 panels in series = 68V, 1 string of 4 = 5A for the wire run to the controller, 12ga wire fine

          Both are well below the 150VDC limit for the professional MPPT controllers. Depending on the wire distance, you may save enough on the wiring to pay for the 2 MPPT controllers. Rogue and Midnight make some rugged entry level MPPT controllers. The Rogue, you may have to check it's input DCv limit.
          Mike, my two trackers are manual trackers that move in both vertical and horizontal directions that look like the old Zomeworks trackers-and will be readjusted seasonally......My panels are already wired with solar USE cable AWG 10, so I'm staying with parallel wiring, but have no fuses installed between panels, so I'll be doing that, and installing a MPPT controller for each array.thanks..........Incidentally, my Arco 16-2000s were originally designed to NOT use a charge controller because their rated 16 volts can't overcharge a 12 volt battery, and I was going to do exactly that, like many did back in the good old days of Home Power magazine editorials. However, I was warned to use a charge controller to keep the battery topped off properly, or "equalized" into staying full. Anyway, what is the bottom line if I insist on combining both trackers at 12 volts into my already purchased Xantrex C-60, a charge controller that can handle up to 60 amps continuous? Joe

          Comment


          • #6
            Originally posted by doubledipsoon View Post
            Mike, my two trackers are manual trackers that move in both vertical and horizontal directions that look like the old Zomeworks trackers-and will be readjusted seasonally......My panels are already wired with solar USE cable AWG 10, so I'm staying with parallel wiring, but have no fuses installed between panels, so I'll be doing that, and installing a MPPT controller for each array.thanks..........Incidentally, my Arco 16-2000s were originally designed to NOT use a charge controller because their rated 16 volts can't overcharge a 12 volt battery, and I was going to do exactly that, like many did back in the good old days of Home Power magazine editorials. However, I was warned to use a charge controller to keep the battery topped off properly, or "equalized" into staying full. Anyway, what is the bottom line if I insist on combining both trackers at 12 volts into my already purchased Xantrex C-60, a charge controller that can handle up to 60 amps continuous? Joe
            The open circuit voltages of 20V and 21.6V are too low to be totally reliable for charging a nominal 12V battery bank, but they should work. And since the two voltages are within 5% of each other you could also parallel them into an MPPT charge controller IF the CC specs say that it will accept that low an input voltage. But better to put each type of panel into a separate series/parallel circuit to get a higher voltage.
            Since they significantly different current values, mixing the two panel types into one series string is not an option.
            SunnyBoy 3000 US, 18 BP Solar 175B panels.

            Comment


            • #7
              Originally posted by inetdog View Post
              The open circuit voltages of 20V and 21.6V are too low to be totally reliable for charging a nominal 12V battery bank, but they should work. And since the two voltages are within 5% of each other you could also parallel them into an MPPT charge controller IF the CC specs say that it will accept that low an input voltage. But better to put each type of panel into a separate series/parallel circuit to get a higher voltage.
              Since they significantly different current values, mixing the two panel types into one series string is not an option.
              inetdog, thanks, that's what I wanted to hear- so, it sounds like I can combine these two trackers at 12 volts. Now, do I need to put fuses in between each panel of each tracker? If the Arcos are 33w/12v @2.7 amps, do I use a 2.7 amp fuse? (or thereabouts?) And if the Siemens are 90w/12v @7.5 amps, do I use a 7.5 amp fuse? (or thereabouts) Thanks

              Comment


              • #8
                Originally posted by doubledipsoon View Post
                inetdog, thanks, that's what I wanted to hear- so, it sounds like I can combine these two trackers at 12 volts. Now, do I need to put fuses in between each panel of each tracker? If the Arcos are 33w/12v @2.7 amps, do I use a 2.7 amp fuse? (or thereabouts?) And if the Siemens are 90w/12v @7.5 amps, do I use a 7.5 amp fuse? (or thereabouts) Thanks
                Inetdog, I just read this off a solar charge controller link- you might be interested........"Beware of some caveats when choosing between MPPT and non-MPPT controllers. First, all the PV modules (or series strings of modules) feeding an MPPT controller should be identical. Mixing modules from different manufacturers; using different PV technologies (monocrystalline, polycrystalline, or amorphous); or using modules with different voltages and different power ratings should be avoided, as MPPT gains can be compromised and mismatched modules could be damaged.".....So it sounds to me that my Xantrex C-60 ( a non-MPPT charge controller) would actually be better to use, yes?

                Comment


                • #9
                  With your low voltage array, MPPT controllers are pointless.

                  My suggestion is, instead of adding all those fuse holders and fuses, rewire into series/parallel as I described, and then you can reap the benefits of the MPPT controllers. It's conceivable that both arrays could go onto one MPPT controller, and work, but as a backup, prepare to add a 2nd controller.

                  Putting both arrays in PARALLEL with each other, will drag the 17v array down to 16v to match the other, lower voltage. There is a great risk to undercharging your batteries with this method in the summer, when the heat causes the array voltage to droop. Hoping for the 21V of unloaded panels to charge the batteries, is pointless.

                  As to the fuses, nobody makes a 2.7 or 7.5a that is affordable. If you can't find 4A fuses, use a 5A, and then for the 7.5, use a 10A

                  good luck
                  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

                  Comment


                  • #10
                    Originally posted by Mike90250 View Post
                    With your low voltage array, MPPT controllers are pointless.

                    My suggestion is, instead of adding all those fuse holders and fuses, rewire into series/parallel as I described, and then you can reap the benefits of the MPPT controllers. It's conceivable that both arrays could go onto one MPPT controller, and work, but as a backup, prepare to add a 2nd controller.

                    Putting both arrays in PARALLEL with each other, will drag the 17v array down to 16v to match the other, lower voltage. There is a great risk to undercharging your batteries with this method in the summer, when the heat causes the array voltage to droop. Hoping for the 21V of unloaded panels to charge the batteries, is pointless.

                    As to the fuses, nobody makes a 2.7 or 7.5a that is affordable. If you can't find 4A fuses, use a 5A, and then for the 7.5, use a 10A

                    good luck
                    Putting the arrays in parallel WILL drag the 17v panels down to the 16v panels, making it really inefficient. And putting the arrays in series/parallel will upset the MPPT charge controller that I mentioned 2 threads ago. According to Xantrex, mixing 2 types of panels, even if they are the same voltage, is NOT recommended, nor is doing a series/parallel into a state of the art MPPT charge controller. I'm not a solar engineer, but I heard it from the horses mouth..........So, I'm going back to PLAN A- rehooking up each array into its own charge controller and inverter and battery bank. So much for an experience in solar complication.....To tell you the truth I prefer the 1979 solar method of hooking panels up directly to the battery WITHOUT a charge controller like the 16-2000s were originally intended. I mean how much money really has to be spent before the law of diminishing returns kicks in. One of my friends just spent $38,000 on his on-grid system- unless he lives another 80 years, he's NEVER going to get his money back!!!!!!Not to mention that solar was originally devised to get OFF THE GRID! It's all going in the wrong direction, like a hellava lot of other things......this threads dead.

                    Comment


                    • #11
                      Originally posted by doubledipsoon View Post
                      Not to mention that solar was originally devised to get OFF THE GRID!
                      In your opinion maybe but in reality no.
                      [SIGPIC][/SIGPIC]

                      Comment


                      • #12
                        Originally posted by russ View Post
                        In your opinion maybe but in reality no.
                        Russ, yeah, it is just my opinion, but, you know reality is "relative" thing. It's kind of like "time". Thanks to people like Einstein, science has learned that there isn't one "reality". I mean, if a energy-conscious individual wants to get into solar, the "current reality" is going to suck you down a hole from which you'll spend a ton of money, hiring a solar engineer who really knows what he's doing @ $300 an hour, and ultimately never recoup the cash you've "saved" off utility bills. You may think that all this is "just my opinion", but the evidence shows otherwise. Since I'm a scientist, I don't mind hearing what solar engineers have to tell me about how out of control the solar industry has gotten. It's no surprise that I live in the windiest and sunniest part of California, and there's ONE wind generator (mine), and a handful of solar panels on the roofs of the rich and famous. Now, could solar exorbitant costs have anything to do with it?

                        Comment


                        • #13
                          Originally posted by doubledipsoon View Post
                          It's no surprise that I live in the windiest and sunniest part of California, and there's ONE wind generator (mine), and a handful of solar panels on the roofs of the rich and famous. Now, could solar exorbitant costs have anything to do with it?
                          Residential wind is generally a loser - more of a pain than useful plus a tall tower is required..

                          Rooftop solar - with the various incentive programs and subsidies it is affordable and practical in places with high power costs.

                          Nothing is out of control - just the greens pushing a technology that isn't ready for prime time yet.
                          [SIGPIC][/SIGPIC]

                          Comment


                          • #14
                            Originally posted by doubledipsoon View Post
                            Russ, yeah, it is just my opinion, but, you know reality is "relative" thing. It's kind of like "time". Thanks to people like Einstein, science has learned that there isn't one "reality". I mean, if a energy-conscious individual wants to get into solar, the "current reality" is going to suck you down a hole from which you'll spend a ton of money, hiring a solar engineer who really knows what he's doing @ $300 an hour, and ultimately never recoup the cash you've "saved" off utility bills. You may think that all this is "just my opinion", but the evidence shows otherwise. Since I'm a scientist, I don't mind hearing what solar engineers have to tell me about how out of control the solar industry has gotten. It's no surprise that I live in the windiest and sunniest part of California, and there's ONE wind generator (mine), and a handful of solar panels on the roofs of the rich and famous. Now, could solar exorbitant costs have anything to do with it?
                            FWIW, a lot of people who believe they are energy conscious are actually energy unconscious. Like everything and everywhere else, there are charlatans and hucksters to make money from the ignorance. They will be with us always, as will the ignorant suckees. Caveat Emptor.

                            Comment


                            • #15
                              Originally posted by russ View Post
                              Residential wind is generally a loser - more of a pain than useful plus a tall tower is required..

                              Rooftop solar - with the various incentive programs and subsidies it is affordable and practical in places with high power costs.

                              Nothing is out of control - just the greens pushing a technology that isn't ready for prime time yet.
                              I appreciate your optimism, but, solar and wind have never been ready for prime time, and still aren't. Back in the early seventies when we all assumed that solar and wind would explode onto the economic scene, we didn't realize how technology would complicate a great idea, make it economically unfeasible for the vast majority of people, and pretty much nip it in the bud. Why? Because solar "hard technology" moved in on solar "soft technology". It's like electric bikes- the reason China has 250,000,000 ebikes and the good old USA has only 250,000 is because they keep it simple, uncomplicated, and cheap. China is off and running into the solar/wind future, while we are making things so complicated and expensive that no one can afford it, or wants to do it. Solar/Wind is not only out of sight and out of reach, it's out of control. Optimism about solar and wind proliferation is simply not tied to the facts. If what you're saying about it being affordable is really true, then where the hell are all the roof-top solar panels? I really want to know. You see, there's still a damn good reason why it hasn't happened.....

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