Announcement

Collapse
No announcement yet.

Off-grid solar panel hit by lightning and not charging

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

  • Off-grid solar panel hit by lightning and not charging

    Hello all,

    This is my first post. I've been reading through the forum and have seen some similar posts answered but my situation is a bit tricky. I took over an off grid solar system in Central America. I wasn't here when it was installed, and the installer hasn't left any manuals or wiring charts, so I've been trying to reverse engineer the whole system. So, I have a few questions and any help would be appreciated.

    We have 30 x 250-watt (38W peak efficiency) solar panels setup in three sets of 10. Each one of these chains of 10 panels is hooked up to one 60-amp charge controller and runs to a battery bank. The battery bank is comprised of 48 x 12v, 200Ah AGM batteries. They are setup as 4 batteries in series to get to 48V and then linked in parallel. Each charge controller (3) is wired to a bank of 16 batteries, or 4 chains of 4 batteries and then these three smaller banks are linked together in parallel to make the whole battery bank. Correct me if I'm wrong, but this would give a battery bank of 48V and 2,400Ah = 115.2kWh. 4 x 12V in series would give 48V and remain at 200Ah and then 12 of these 48V sets would give the 2,400Ah.
    1. Does this make the most sense as a setup?
    I ran the math with the solar panel and battery bank configuration and it all makes sense, but the batteries aren't holding a charge. Before I got here, the system had been hit by several lightning strikes and is surprisingly not grounded. The LED screen blew out and the batteries weren't getting charged. I changed the 60amp DC breakers out for new ones and they began charging again but now they won't hold a charge. This led me to think that it was the backflow diodes that blew. My problem is, the charge controllers don't have backflow diodes and they're actually inside the PV junction box on the inverse of the solar panels. So, my two main questions here would be:
    1. Do the backflow diodes make the most sense as the issue? My thinking is, they're discharging when the sun goes down and the LED lights in the inverter screen blew out, which are the most common indicators of a non-functioning blocking diode.
    2. I've never installed a backflow diode but I'm wondering if I can install 3 backflow diodes where each set of 10 solar panels come together in a junction box so that I don't have to install 30 diodes or replace the PV junction box.

    Other possibly useful information:
    Solar panel's Imp is 8.39A, VMP is 30.4V and maximum system voltage for the panels is 1000V.

    I know this might be a little all over the place. If something isn't clear, please let me know and I'll re-explain it more clearly.
    Thanks in advance for any help!

    Sashaky
    Last edited by sashaky; 09-17-2018, 12:36 PM.

  • #2
    back flow diodes are in the Charge Controller.
    If the system was hit by lightning, consider everything but the batteries, toast.
    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 sashaky View Post

      We have 30 x 250-watt (38W peak efficiency) solar panels setup in three sets of 10. Each one of these chains of 10 panels is hooked up to one 60-amp charge controller and runs to a battery bank. The battery bank is comprised of 48 x 12v, 200Ah AGM batteries. They are setup as 4 batteries in series to get to 48V and then linked in parallel. Each charge controller (3) is wired to a bank of 16 batteries, or 4 chains of 4 batteries and then these three smaller banks are linked together in parallel to make the whole battery bank. Correct me if I'm wrong, but this would give a battery bank of 48V and 2,400Ah = 115.2kWh. 4 x 12V in series would give 48V and remain at 200Ah and then 12 of these 48V sets would give the 2,400Ah.[LIST=1][*]Does this make the most sense as a setup?
      None of it makes any sense whatsoever. But I am only going to comment on your batteries and controllers because it is not worth my or your time to educate you. They are a boat anchors and need re[placed along with all your charge controllers. Before you spend $20,000 replacing Batteries and Controller, I suggest you get a proper working design, or else you will be doing this again in a year or two. .
      Last edited by Sunking; 09-17-2018, 01:04 PM.
      MSEE, PE

      Comment


      • #4
        It sounds like lightning took out your charge controllers, then the batteries have been run down and ruined.
        Battery guys chime in.

        I would say the first concern is to learn how to survive most lightning. All the panel frames could be grounded
        using serious methods such as rebar in concrete, with Cadweld connections to the rebar. That may not be
        enough, but you could build a set of overhead wires that surround the array and are well grounded on their
        own, to distract direct lightning to the array. Like that extra wire you see on transmission poles, at the top
        above all the main conductors. Study and design needed.
        Bruce Roe

        Comment


        • #5
          So I looked up my charge controllers: TriStar TS-60, and they don't actually have backflow diodes even though most modern charge controllers do. The PV junction on the back, JM828 PV junction box, contains them. The problem is, they don't have an easily accessible mother board so I'd have to instal them in between the junction box and the charge controller. That's why I was thinking of doing it after the charge controller. The batteries do get up to 52V when they're full, which is around 95% of their manufactured max. I thought and hoped, because of this, they're not toast. I can get backflow diodes for $3 where I am so wanted to try installing those before trashing the whole system.

          Comment


          • #6
            Originally posted by bcroe View Post
            It sounds like lightning took out your charge controllers, then the batteries have been run down and ruined.
            Battery guys chime in.

            I would say the first concern is to learn how to survive most lightning. All the panel frames could be grounded
            using serious methods such as rebar in concrete, with Cadweld connections to the rebar. That may not be
            enough, but you could build a set of overhead wires that surround the array and are well grounded on their
            own, to distract direct lightning to the array. Like that extra wire you see on transmission poles, at the top
            above all the main conductors. Study and design needed.
            Bruce Roe
            Thank you for your help. If I were here when it was installed, I would have insisted on grounding it. Because I don't want to take them up and move them, I was thinking of trying to retroactively ground the system but this is obviously much more difficult. This would also hopefully prevent the same issue from happening again.

            Comment


            • #7
              Originally posted by sashaky View Post
              So I looked up my charge controllers: TriStar TS-60, and they don't actually have backflow diodes even though most modern charge controllers do.
              What are you talking about? No modern Charge Controller has backflow diodes. All modern controllers use MOSFET's transistors and like a diode current can only flow in one direction.
              MSEE, PE

              Comment


              • #8
                Originally posted by Sunking View Post
                None of it makes any sense whatsoever. But I am only going to comment on your batteries and controllers because it is not worth my or your time to educate you. They are a boat anchors and need re[placed along with all your charge controllers. Before you spend $20,000 replacing Batteries and Controller, I suggest you get a proper working design, or else you will be doing this again in a year or two. .
                Ya I agree, the setup doesn't make much sense but as I said earlier, I wasn't there when it was installed. What I'm trying to do is fix the problem and prevent it from occurring again in the future without ripping up the whole system and starting from scratch.

                Comment


                • #9
                  Originally posted by Sunking View Post

                  What are you talking about? No modern Charge Controller has backflow diodes. All modern controllers use MOSFET's transistors and like a diode current can only flow in one direction.
                  I thought I had read that somewhere, I must have misread or misremembered. So the charge controllers act LIKE a backflow diode but use MOSFET? If I were to get new charge controllers, and got it properly grounded, do you think this would fix the problem? Again, the batteries are charging fine and get up to 52V so i have no reason to believe that the batteries or panels are severely damaged.
                  thanks for the help! I've tried to ask electricians where I am, and they are very unhelpful and refuse to help since I'm in a remote area.
                  Last edited by sashaky; 09-17-2018, 02:10 PM.

                  Comment


                  • #10
                    Originally posted by Mike90250 View Post
                    back flow diodes are in the Charge Controller.
                    If the system was hit by lightning, consider everything but the batteries, toast.
                    Amend to read Backflow diode function provided by the Charge Controller. The controller can use many methods to achieve this function.
                    (Diode, MOSFET, relay, magic...)

                    What's inside the PV panel J-box, is the 2 or 3 Bypass Diodes, in case shade falls on some or all of the panel.

                    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


                    • #11
                      Originally posted by Mike90250 View Post

                      Amend to read Backflow diode function provided by the Charge Controller. The controller can use many methods to achieve this function.
                      (Diode, MOSFET, relay, magic...)

                      What's inside the PV panel J-box, is the 2 or 3 Bypass Diodes, in case shade falls on some or all of the panel.
                      Thanks Mike. So that is where the bypass and backflow diode would be? I have spoken to Morningstar, the manufacturer of the charge controller, and they told me the actual solar array is not setup correctly. The 3 sets of 10 solar panels have a voltage that exceeds the maximum of the charge controller so I am looking into exchanging them for mppt charge controllers and re-arranging the solar array.

                      Comment


                      • #12
                        The lightning subject is always interesting.

                        My house is steel framed posts into concrete and a concrete slab onto ground for part of it. Stand alone system with a generator in another shed 50m away. Its A/C electrical system is earthed to Australian standards, I assume, as it was done by qualified electricians.

                        there is nothing special done for lightning protection.

                        In over 10 years I have had problems from lightning from surge coming in the copper phone lines, or through the ground blowing computers etc.

                        There have been a lot of really, really close lighting strikes, but not a direct hit on the house or I think it would frazzle everything and probably melt the house??

                        I have been zapped sitting at the desk from surge coming through the phone line or the ground.

                        But neither panels, charge controllers or inverter have ever been damaged but any lighting surge.

                        Comment

                        Working...
                        X