combiner boxes

SolarjimmySolarjimmy Registered Users Posts: 1
I need help with my combiner setup. I have a controller that can take 60 amps and 100 volts. I have 6x200w solar panels that put 37 volts and 5.41 amps. I can run two panels in series with no problems. So I buy a combiner box and wire two panel in series with two more in series a total of 4 solar panel. I wired them in the the controller box I check the voltage and it read 148 volts two much for my controller. What did i do incorrectly?


  • BB.BB. Super Moderators, Administrators Posts: 33,319 admin
    Welcome to the forum SoalrJimmy,

    Just to confirm, your panels are Vmp~37.0 Volts and Imp~5.41 Amps @ standard test conditions.

    And you have an MPPT controller that is rated for Vpanel max input voltage of 100 Volts.

    Voc and Vmp rise in cold weather--Assuming you are in Iowa or Nebraska at this time--Looking at warm to hot weather.

    The panels will reach Voc (voltage open circuit) with zero load and even weak morning/evening direct sunlight. (and under full sun, Voc-panel will be about the same--As panels get hot, Voc and Vmp do fall to almost 80% of Std ratings).

    Anyway, with two panels in series, the will only be at ~80+ VDC Voc or so. The only way you are getting 148 volts is if you have 4 panels in series.

    It sounds like you have all your panels in series (upper left).

    What you want is 2 series x 2 parallel (the lower two drawings.

    You are correct, you do not want to over voltage the Vpanel input for your solar charge controller--It will fry the controller.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
Sign In or Register to comment.