current differences between panels

I have 4 Kyocera KC130TM panels on my roof. All of them were bought and installed at the same time on the same roof at the same angle.

I have them wired in two pairs and each pair is parallel wired. So there are 4 wires to the combiner box wired to 2 breakers. I am finding that one pair puts out more current than the other pair. For example right now, measuring the current I am getting 14 amps from one pair and 10 amps from the other. I am using a good clamp-on meter for these measurements and my controller confirms the aggregate total current.

Is this a common thing or is there something wrong somewhere in the second pair?

Comments

  • icarusicarus Solar Expert Posts: 5,090 ✭✭✭✭
    Re: current differences between panels

    Shading on a string, poor wire connection, corrosion on a fitting, poor contact in the breaker or the breaker lugs,,,

    What happens if you un-wire one string?

    (I am assuming that the panels are identical specs).

    Can you test each panel by itself?

    Tony
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: current differences between panels

    Also check for leaves, bird souvenirs, dirt, etc. on the low-output pair.

    HTH,
    Jim / crewzer
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: current differences between panels

    i would advise after making sure nothing else like shading, connections, or dirt is the problem to test each pv individually. i know this may not be easily done depending on where it's mounted, but there may be a problem with one of the pvs.
  • System2System2 Posts: 6,290 admin
    Re: current differences between panels

    I spoke too soon. There wasn't any problem at all. It was the angle of solar incidence that was causing this difference. As noon approached the difference slowly disappeared and after noon the other pair was producing more current. Thanks for the replies. I'll take more time to investigate before posting next time.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: current differences between panels

    no problem, but we had assumed, wrongly i guess, that they were all aimed in the same direction.
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