My solar system is only producing 50 % or less power then it used to ??

Solar world panels set up in two runs , connected to SMA 6000 US Inverter...      all was working great when I left the house 4 months ago...    what could cause this...avg 30 to 40 KW a day now lucky to make 15 KW..


  • VicVic Solar Expert Posts: 3,176 ✭✭✭✭

    Hi casa..,

    We know very little about your system.   One to look for,  might be some shading of the PV Modules.   Even small shadows can significantly reduce the output.

    There are a number of other things that could cause this.   Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • ThomThom Solar Expert Posts: 196 ✭✭✭
    Not sure whare u are ? But November is my 2nd worst month for solar. Short days 

    Off grid since 1984. 430w of panel, 300w suresine , 4 gc batteries 12v system, Rogue mpt3024 charge controller , air breeze windmill, Mikita 2400w generator . Added [email protected] 100w panel with a midnight brat 
  • casabonita15casabonita15 Registered Users Posts: 3
    No shade on panels ,    clear sunny days,,,    on cloudy day here in Mazatlan mexico I make 15 KW,,    I have recorded all output  for the last two winter everyday  , the norm is 30 to 40 Kw per day  ...   

  • Dave AngeliniDave Angelini Solar Expert Posts: 6,294 ✭✭✭✭✭
    edited November 2015 #5
    Isolate the 2 strings of panels and test each one for a day. If your inverter has 2 MPPTS, you can reverse the strings and check the outputs. I spent many years in Mazatlan on board  SV Astraea. Enjoy it!  

    Oh yea, you do know about how careful one must be with high DC voltages right?
    "we go where power lines don't" Sierra Nevada mountain area
    E-mail [email protected]

  • solar_davesolar_dave Solar Expert Posts: 2,395 ✭✭✭✭
    edited November 2015 #6
    Dave gave you good advise. My system had 8 strings of 9 panels and the production dropped down, it was 2 fuses blown in the combiner that were pretty undersized at 8 amps.  Had the electrician replace them with 10 amp fuses and all was well.  I found it much the same way, I have 2 5200 watt inverters and one was getting substantially less watts which lead me to tell the electrician to check the at combiner first, he pretty quickly found the fuse issue and kept my time and materials to a minimum.
  • BB.BB. Super Moderators, Administrators Posts: 32,916 admin
    Get a DC Current Clamp DMM (digital multi-meter). This one from Sears (US Link) is "good enough" for our needs and pretty cheap.

    Measure the current through each string... You will probably find one string that is supplying much less current than the others.

    Check the wiring, fusing/breakers.

    In my case, it was the solar panels that went bad (problem in the j-box and my whole array needed to be replaced).

    On my panels, looking closely at just above the j-box (BP 4175 panels under the glass), I could see a light brown/coffee colored staining (apparently from overheating) on about 1/2 of my panels.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,294 ✭✭✭✭✭
    I hate it when they look like coffee under the glass....
    "we go where power lines don't" Sierra Nevada mountain area
    E-mail [email protected]

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