Announcement

Collapse
No announcement yet.

Troubleshooting low to zero output on older SunPower SPR-2000 / SPR-200 setup

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

  • #16
    Originally posted by bcroe View Post
    I have some of those, 36V per panel, or 180V loaded from a string of 5. Open
    circuit (unloaded) voltage might be around 225V.
    Ok this 205V DC reading makes some sense now. If each panel is 47.75, multiply that times 5 and get 238.75V DC. Given that the panels are 16 years old, I would expect some degradation. So that max of 205V is probably normal for open circuit.

    Comment


    • #17
      If the inverter faults out again, follow the Sunpower start up procedure stated above. If you get a bunch of blinking LED's and/or fault codes, refer to the manual.

      Since nobody else has suggested it, try to clean your panels very very early in the morning since you clear your panels in the summer. i.e. when you can see good enough to see to get on the roof without falling, but before the sun makes its appearance over the horizon in Central Oregon. The morning sun can be very hot in Central Oregon.

      Comment


      • #18
        I am going to suggest another test. Voltage tells you something, but is not
        useful without the ability to deliver substantial current. Here is my test light,
        4 incandescent bulbs wired in series since my array runs near 400VDC. The
        75 watt bulbs draw around 0.6A, which the panels should have no trouble
        delivering under descent sun. If they cannot, they cannot keep an inverter
        going either. You would only need 2 bulbs in series, nothing magic about
        my choice of 75W bulbs, the array should even run the inverter at the same
        time at reduced output.

        If this load collapses your array voltage to a lot less than 8/10 of open circuit,
        there is high resistance developed in either the wiring or the cells.
        good luck, Bruce Roe

        PVtestLt.JPG

        Comment


        • #19
          Originally posted by oregon_phil View Post
          If the inverter faults out again, follow the Sunpower start up procedure stated above. If you get a bunch of blinking LED's and/or fault codes, refer to the manual.
          The inverter's only faulted once - and that was when I deliberately removed the 600V GF fuse and powered the inverter on just to verify it would complain, and it did. Replaced the fuse, did another reboot, and back to "normal" behavior (fault 0000 0000 0000 for 5 minutes, negative AC output for 5 minutes, then back to fault 0000 0000 0000)

          I will give the panels another cleaning tomorrow morning. But what I really want to do while up there is inspect and label the wires.

          Comment


          • #20
            Originally posted by bcroe View Post
            Here is my test light,
            4 incandescent bulbs wired in series since my array runs near 400VDC.
            I like the idea, but haven't owned an incandescent bulb since 2015, lol. Guess I can get some at the hardware store. Stupid question though - don't bulbs require 120V AC 60 Hz?

            Also, one thing that did bother me yesterday: the orange and yellow strands always showed the exact same voltage, but it seems they should be slightly different (same ballpark though, since both are 5 panels facing the same direction). I unplugged them from the inverter I see 217 for orange and 203 for yellow which made more sense.

            Shouldn't the PV input be the combination of those two, since the strands get aggregated?




            IMG_1939.jpgIMG_1940.jpg

            Comment


            • #21
              That is a quite old inverter. From the very early days of grid-tie technology and probably only came with a 5 year warranty. Its a boat anchor (no really, recycle it...) Time for a new string inverter. Make sure it can handle those reverse polarity, positive grounded Sunpower wierd panels...
              BSEE, R11, NABCEP, Chevy BoltEV, >3000kW installed

              Comment


              • #22
                Originally posted by johnnylingo View Post

                I like the idea, but haven't owned an incandescent bulb since 2015, lol. Guess I can get some at the hardware store. Stupid question though - don't bulbs require 120V AC 60 Hz?

                Also, one thing that did bother me yesterday: the orange and yellow strands always showed the exact same voltage, but it seems they should be slightly different (same ballpark though, since both are 5 panels facing the same direction). I unplugged them from the inverter I see 217 for orange and 203 for yellow which made more sense.

                Shouldn't the PV input be the combination of those two, since the strands get aggregated?

                IMG_1939.jpgIMG_1940.jpg
                An incandescent light bulb is a resistor. You can check this out by using your DVM.

                Are you well versed in High voltage DC electricity? Be very careful with what you are doing. Google DC arcing. You can do exactly the same thing in a safer manner by turning off your DC disconnect. Then measure string 1 positive on the disconnect to string 1 negative in the inverter. From the picture, it looks like only the positive DC lines are switched (open and closed) in your DC disconnect. Do the same for string 2.

                Even after reading the manual, it is unclear to me how your inverter handles each string. I don't have enough inverter knowledge to know how inverters were constructed before 2018. It might be that the inverter inputs just combined/paralleled the two strings together. This makes sense since you get the same exact number.

                Comment


                • #23
                  Originally posted by solarix View Post
                  That is a quite old inverter. From the very early days of grid-tie technology and probably only came with a 5 year warranty. Its a boat anchor (no really, recycle it...) Time for a new string inverter. Make sure it can handle those reverse polarity, positive grounded Sunpower wierd panels...
                  Since the OP asked about reusing the solar panels as part of a future upgrade, what's the chance these weirdo Sunpower positive panels working with a modern string inverter?

                  Comment


                  • #24
                    Originally posted by solarix View Post
                    Make sure it can handle those reverse polarity, positive grounded Sunpower wierd panels...
                    The inverter is very old. I get it. What exactly is so weird about the panels?

                    Comment


                    • #25
                      Originally posted by johnnylingo View Post
                      . I like the idea, but haven't owned an incandescent bulb since 2015, lol. Guess I can get some at the hardware store. Stupid question though - don't bulbs require 120V AC 60 Hz?

                      Also, one thing that did bother me yesterday: the orange and yellow strands always showed the exact same voltage, but it seems they should be slightly different (same ballpark though, since both are 5 panels facing the same direction). I unplugged them from the inverter I see 217 for orange and 203 for yellow which made more sense.

                      Shouldn't the PV input be the combination of those two, since the strands get aggregated?
                      The knee jerk law makers have been quick to bad mouth the incandescent bulb, but it
                      has been proved in for more than a century, unlike SOME of the expensive junk lately
                      peddled. They do not generate radio interference, and are not going to burst into
                      flames if the inverter section of non incandescent faults. For a seldom used space,
                      especially in an unheated structure, incandescents can provide occasional light even
                      in our -20F winters. I have a few used in winter while I wait for the fluorescents to
                      warm up. They are not an energy efficient solution for heavy use.

                      Incandescents convert electric energy flowing into the filament into heat, they care not
                      of polarity, DC, AC, or radio frequency. Work well in cars, flashlights. If you just want
                      light, run them at the voltage rating for that service.

                      As a test device incandescents will give indication below half that voltage.
                      They can provide a cheap, compact, self indicating dummy load. The resistance is not
                      at all constant with applied voltage, some I have tested draw nearly a constant current
                      from rated voltage all the way down. Some were used as bleeders preventing power
                      supplies from long retaining energy after shutoff, wasting a lot less energy than a fixed
                      resistor of similar time constant when turned on.

                      Incandescents serve me well providing a fairly constant current load with all the above
                      advantages, for any voltage in my PV system. They will immediately indicate a serious
                      lack of current capability, and give no false readings from any static or too high impedance
                      sources like a DVM does. Also useful for bleeding down shutoff charge in a DC device
                      (capacitor).

                      I would test each string while isolated to be sure they are both current capable. Running
                      the inverter, bulbs should dim, with about 4/5 the voltage still available. An MPPT inverter
                      will pull the voltage down that much to get more current, maximizing energy flow. In
                      the process the 2 strings (wired in parallel) will be forced to run at the same voltage.

                      Bruce Roe
                      Last edited by bcroe; 04-11-2021, 08:55 AM.

                      Comment


                      • #26
                        Originally posted by johnnylingo View Post

                        The inverter is very old. I get it. What exactly is so weird about the panels?
                        Search for a thread on this forum Sunpower Panels and Positive Grounding.

                        You mentioned in your first post that, if possible, you might want to salvage and move some of the equipment when you upgrade your system. Moving your equipment may trigger you to upgrade your system to current NEC regulations. Only your local authorities can answer that question. My local authority in Oregon did not require me to upgrade my entire system to NEC 2020 when I replaced my inverter last year. The inverter was installed in 2018, but NEC regulations have changed quite a bit from 2014.

                        Comment

                        Working...
                        X