Defective Kyocera solar panel?

I have two KC120-1 (120 watt) solar panels on my boat.

They are wired in parallel to a Morningstar Prostar P-30 controller. I monitor battery state/charge rate via a Xantrex Link 20 battery monitor. I've not rewired/changed anything since the original installation in early 2005 (I'm the original installer and understand the installation intimately).

I just noticed my batteries were not being charged to the degree I've come to expect. Upon examination it appears one panel is not outputting the amps I normally get during sunny days. With both panels in the sun, if I isolate the 'good' panel I get 5('ish) amps. If I isolate & switch to the other panel I only get .1-.3 amps.

I disconnected the panels from the controller and checked the (open) voltage. Both panels are outputting 17 - 18 volts. Under load I'm getting 13.2 v from both panels. I checked the diodes on the panel not supplying amperage using a Fluke meter and they check out OK.

I've checked (and cleaned) all wiring/connectors/grounds/etc.. I'm not sure what else to check.

Think I may have a defective panel? If so, how do I obtain a warranty replacement (no contact/tech support info on the kyocera website)

Comments

  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Defective Kyocera solar panel?

    For contact info:

    http://www.solar-guppy.com/forum/kyocera-kc-120-panel-failure-t233.html

    I would pull the suspect panel and look for burn marks, typically when a solar panel fails either is a interconnection failure on the metal strips or the diodes short out.

    I'm not sure panels are warranted in marine applications.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Defective Kyocera solar panel?

    First, try and set your DVM to 10 amp full scale and "short" the panel output by connecting the DVM (in Current Mode) to the panel pigtail/connection points (you will not damage a single panel by shorting it out with a amp-meter).

    If the two panels read the same Isc (current short circuit)--you have an 80-90% chance that they are both good. (it is possible that 1/2 the array is bad and the bypass diode is going around the bad section at zero volt output)

    The second test is to measure the panel current when charging your 12 volt battery (either through your controller, or directly connected to your 12 volt battery --- being very careful to observe correct polarity--backwards connections will ruin the panel). If the current is still good--then there is something else wrong.

    If, you figure out you have a bad panel, take a look at Solar Guppy's website for:

    KYOCERA KC120 KC-120 panel failure contact warranty info
    2000-2002 year of manufactured Kyocera KC-120 aka KC120 panels have been reported to have bad batch's of panels that fail with interconnection failures and faults. No output, low output, intermittent output are reported symptoms and visually one can see burn or brown spots on the backside of the panel.
    So far--Kyocera has been good at replacing bad panels (and sometimes including the entire set--even if only a few are bad) with remanufactured or new panels.

    -Bill

    PS: What "the Guppy" has said.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Westsailor
    Westsailor Registered Users Posts: 5
    Re: Defective Kyocera solar panel?
    For contact info:

    http://www.solar-guppy.com/forum/kyocera-kc-120-panel-failure-t233.html

    I would pull the suspect panel and look for burn marks, typically when a solar panel fails either is a interconnection failure on the metal strips or the diodes short out.

    I'm not sure panels are warranted in marine applications.

    Thanks for the link.

    Physically, the panels look like new... no hot spot/burn marks on the back, front is clear, etc..

    The way I checked the diodes was with a Fluke digital meter with a 'diode' setting. I removed the diodes and put the leads across the diodes. One way I measured 0 volts. Reversing the leads I measured a voltage of .435-.437 v across each diode. Since it was passing V one way and blocking it the other I "assume" they are good (not open or shorted/leaky).

    It wouldn't bee too difficult to just replace them anyway if I knew what they were in more common terms (e.g. a 1N400X)
  • Westsailor
    Westsailor Registered Users Posts: 5
    Re: Defective Kyocera solar panel?
    BB. wrote: »
    First, try and set your DVM to 10 amp full scale and "short" the panel output by connecting the DVM (in Current Mode) to the panel pigtail/connection points (you will not damage a single panel by shorting it out with a amp-meter).

    OK, I did this but only on the suspect panel (measured zero current). I'll disconnect them and compare current at each panel.

    I did measure *voltage* on both panels and they were essentially the same (17.5-18v unloaded). That's what I can't figure out... why both panels exhibit proper voltage yet only one is putting out normal current.
    BB. wrote: »
    The second test is to measure the panel current when charging your 12 volt battery (either through your controller, or directly connected to your 12 volt battery --- being very careful to observe correct polarity--backwards connections will ruin the panel). If the current is still good--then there is something else wrong.

    -Bill

    PS: What "the Guppy" has said.

    I think I've effectively done this by disconnecting each panel and checking the charge current for each one on my Xantrex link 20 battery monitor. That's when I see one panel putting out 4-5 amps while the other only puts out .1-.3 (with both in full sun).
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Defective Kyocera solar panel?

    I think you have demonstrated you probably have a bad panel.

    The fact that you read 17-18 volts on the "bad panel" is reasonable... Normally, the bad panels do not "open"--but just burn through and get a high resistance connection.

    A typical DVM has >1 MegOhm (1,000,000 Ohm input resistance)--so the burned area still connects just enough current for the DVM to read normal voltage--but not near enough current to carry full current.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Defective Kyocera solar panel?

    the other pv may be going bad too and most likely both need replaced even with 5a showing up for it.
  • Westsailor
    Westsailor Registered Users Posts: 5
    Re: Defective Kyocera solar panel?

    Just a follow-up. I contacted Kyocera, described the problem and they are replacing both panels with (certified refurb) KC-120-R's under warranty.

    I can't find any specs on the 'R' model, specifically whether it has a 'pigtail' or junction box). Or maybe it is just a designation for refurbished?

    I must take my hat off to Kyocera for standing behind their products this way.
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Defective Kyocera solar panel?

    There were never KC-120's that had MC cables, I believe it was only available with J-Box's

    The "refurbs" are returns that were either repaired or screened to be OK. When Kyocera see's multi failures, they swap out the entire arrays even if there were for example 5 failures out of 20 panels, this gives them a lot of panels to have as refurb stock