"Tracks" on the solar panels. What are they and should I be concerned?

cruiser guy
cruiser guy Solar Expert Posts: 87 ✭✭✭✭
I added a few more panels to my array the other day and noticed these marks on the older panels. These "older" panels have been in service for about 4-5 months.

I am living in Mokanji, Sierra Leone and we have just come out of the rainy season with thunder and lightening. The panels are grounded using a #12 wire to a ground rod. The house is surrounded by trees which are higher than the house and solar panels but I have full on sun almost all day (from about 9 - 10 AM to about 4 PM).

What is the cause of these marks and should I be concerned? They look like a burn track or something similar on the actual photo-voltaic chip not the glass cover.

Thanks

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    it's hard to say looking at it like this, but it almost looks like moisture tracks. can you verify there aren't any small cracks on the glass? can you verify it is outputting as it should?
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    I think you got water, from water vapor intrusion. There may be pinholes / scratch marks on your protective backsheet. No way to easily fix that I know of. Time to figure if your warranty will apply.
    Powerfab top of pole PV mount | 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 ,

  • cruiser guy
    cruiser guy Solar Expert Posts: 87 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    No obvious cracks anywhere that I could see. These did get shipped half way around the world though so lots of jostling and bumpy roads. There seems to be a little drop in performance but I never had a good meter to measure with before so I was unable to check initially.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    you might want to check with the manufacturer and see what they say about it. let us know of any updates.
  • jkhawaii
    jkhawaii Solar Expert Posts: 30
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    Just wondering, what brand of panel is that?
  • jkhawaii
    jkhawaii Solar Expert Posts: 30
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    and yeah, I'm no expert but that does not look normal
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    Snail tracks ? But what would snails be doing on a hot PV panel.

    They all look like they are connected, and may be radaiting out of the lower part of the photo.
    Powerfab top of pole PV mount | 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 ,

  • cruiser guy
    cruiser guy Solar Expert Posts: 87 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    Some look like they are connected and some not. Not all PV cells on any panel are affected either.

    I'll try the manufacturer.
  • bmet
    bmet Solar Expert Posts: 630 ✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    Could it be a pinhole in the tempered glass? compromise in the backing?
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    is your PV output changing? If not just monitor and get some spray sealant, like used in rain gutters and reseal the back. check with the manufacturer re compatibility with the backing. Hopefully you do not have to replace.
     
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    West Chilcotin, BC, Canada
  • cruiser guy
    cruiser guy Solar Expert Posts: 87 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    I'm in contact with the manufacturer on this issue and have referred them to this thread as well. So far we do not know the cause but there do not think it will affect panel output.

    How does one test panel output? Is it volts or amps? I can test DC volts but I cannot test more than a few milliamps.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    You need to test both volts and amps... It is possible for a panel to read Voc OK and Isc just fine... What you need to be sure is Vmp*Imp measurements.

    If you have several panels in series, you can measure the voltage at each panel connection. Ideally, all panels should have the same Vmp and add up to the Vmp-array voltage.

    If instead, you find two panels read high and one reads low voltage (example of three panels in series passing current to a charge controller with battery drawing current--less than full), then you probably have problems.

    I know you are no where near a US Sears store--but next time you can, a DC Current Clamp Meter is really handy for diagnosing current flow in the array (look for parallel strings with high/low current readings; and for parallel battery strings for unbalanced current during heavy charging/discharging). The clamp meter I have linked is fairly inexpensive ($60 USD or so), and does include the other standard DMM (digital multi meter) functions. Not a Fluke $300-$400 meter--but works well enough.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    the current is what you would be interested in. maybe you know somebody with a dmm that can test the short circuit current? if you get a meter that can read the full isc remember to have it inline with a switch to allow just enough time to get a reading and shut it off as it will heat the wires. the switch is to take the sparking off of the pv leads, but you could also have somebody uncover and cover the pv quickly so the switch won't be needed.

    even if the output is fine right now, there would be future problems with the pv if those are indeed moisture tracks. if after many days straight of sun and no rain, does it look as though the tracks diminish somewhat?

    btw, bb's idea, "If you have several panels in series, you can measure the voltage at each panel connection." is a good one if your pvs are in series and do the measurement while under a constant load/sunshine to stop it from showing variable readings.
  • cruiser guy
    cruiser guy Solar Expert Posts: 87 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    OK, I finally got a DC clamp-on ammeter (ended up with a Fluke clamp attachment). I measured amperage from the three banks of solar panels the other day in full sun and all were within 0.1-0.2 of each other (from memory it was 6.9amp, 6.9 amp and 6.7 amp). This was with the panels connected to the system and operating (not a short circuit amp reading). Two panels are 125w panels and the other four are 135w panels so I'm assuming that is what is contributing to the slight amperage difference.

    Should I be concerned? Everything seems to operate fine. I get a full charge with full sun and I'm able to get the batteries bubbling at that point.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    Sounds like all is working well.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?
    OK, I finally got a DC clamp-on ammeter (ended up with a Fluke clamp attachment). I measured amperage from the three banks of solar panels the other day in full sun and all were within 0.1-0.2 of each other (from memory it was 6.9amp, 6.9 amp and 6.7 amp). This was with the panels connected to the system and operating (not a short circuit amp reading). Two panels are 125w panels and the other four are 135w panels so I'm assuming that is what is contributing to the slight amperage difference.

    Should I be concerned? Everything seems to operate fine. I get a full charge with full sun and I'm able to get the batteries bubbling at that point.

    Encouraging!

    The pattern of the tracks reminds me of electrostatic discharge forkings, but the fairly uniform width (possibly thicker near the common point) has to be indicating something. It does not appear to me to be moisture related, by the pattern, especially if the bottom of the picture is the low edge of the panel.

    If there is a protective coating on top of the cells, and/or a thin conductive layer to act as the electrode, this may be a disruption of that layer, as a result of a static discharge (lightening related?)

    Do you know whether the tracks appeared fully formed or "grew"? Or have you not been looking at the panels often enough to tell?

    If you can measure the voltage under load of each of the panels in a string independently, a difference there could indicate that the current is being forced to be the same but one or more sets of cells in the tracked panel could still not be contributing. (But the near-identical current for the strings which are paralleled to the same voltage would probably rule that out.
    SMA SB 3000, old BP panels.
  • cruiser guy
    cruiser guy Solar Expert Posts: 87 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    It's not really easy to check the panels on a regular basis as they are on the roof and roofs here in Africa are very light corrugated tin. I've got to be real careful where to step. I usually send a kid up to clean them as my 190 lbs makes the tin complain!
    I noticed the markings when we added the 4 135w panels. These markings are on the older 125w panels.
    Sounds like all is OK though.
  • dhsola
    dhsola Solar Expert Posts: 38
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    I have the same thing on some of the Kyocera 135w panels.
    I think I first noticed this last year when the panels were about one year old.

    Before contacting Kyocera, I did the so-called shade test. That is, we covered a single panel in the series string, noted the volts and amps at the charge controller, then covered the next panel in the string, etc. Each shade test gave similar results.

    We then sent photos to Kyocera. They said,
    "[FONT=&amp]The modules are showing what is called a “snail track”. This is usually not a performance issue, but a cosmetic issue only. It is basically indicating a cracked cell. Cells can be broken during installation or transportation and not show until months after they are installed. Whether the cracks reduce power or not depends on whether there are “islands” within the cell surface that are not electrically connected to any of the 3 main silver buss lines on the top surface of the cell. If the cracked areas are connected to at least 1 buss line then the electrons can flow and the output power will not be affected. From what I can see in your photos, you should not have any power output issues. Generally, the cracks are stable and you should not see any further progressions."

    [/FONT]
    [FONT=&amp]I also have some discoloration above the J boxes on some panels. A kind of browning or yellowing. Kyocera said,[/FONT][FONT=&amp]
    [/FONT]
    [FONT=&amp]"Do the modules with the yellowing above the j boxes spend the most time in shadows during the typical day (summer or winter)? I am wondering about the yellowish above the Jbox…..thinking that the modules are shadowed while others in the array are not. If this is the case, the bypass diodes will be conducting and creating heat inside the box (which is normal). Nothing to be concerned about as they are designed to handle it. Reduce the shade….if you can."

    [/FONT]
    Personally, I think the panels were mounted too close to the roof. We get temperatures over 115 F here. I've since increased the 'ventilation space' between the panels and the roof to about six inches (which also increased the power output from what I had been getting. Another indication the panels were too hot).
    As well, there is considerable shading in December, January
    .

    We've had another summer since I raised the panels higher off the roof and they are performing just fine; "snail tracks" and all. We get about 79% - 80% of the nameplate. :D
  • cruiser guy
    cruiser guy Solar Expert Posts: 87 ✭✭✭✭
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    Good to hear! I'll believe the cracked panel/cell explanation. The first two panels were not brought into the village by me personally but were in the stuff we sent over in a container. Transport here is a joke as far as taking care of the customers items. I can't think of the amount of items which were damaged or simply failed to arrive.
    The remaining panels were brought in by me personally and I took great care in ensuring they arrived safely.
    Our panels are 12" off the roof so not too much concern with overheating as we've got as much ventilation as possible beneath them. It's always 70+ here.
  • dhsola
    dhsola Solar Expert Posts: 38
    Re: "Tracks" on the solar panels. What are they and should I be concerned?

    One of the pics sent to Kyocera: