jasonhc73
Cat herder, and dog toy tosser.
Connect all your panels and measure the VOC with a multimeter. If you are under 250V then there you go. Only use the VOC number. Don't complicate it with any other value.Little confused.
At 120a PV max input x 48v only equals 5750w as the max PV input. 6500w ÷ 48v = 135a, so why 120a max input. So it can't handle 6500w input? Am I missing something? Do I need another solar controller to get another string to get to 6500w in if I can use 6500 out.
If you use very common solar farm and residential panel of 250w 38v, 5 of them gives you 190v x 1.2 for cold coefecient = 228v so a series of 5 is your max with our cold desert mornings. Then if you try to get to a maximum amount of panel input it almost does 5s5p.
250w x 5s panels =1250w x5p = 6250w then ÷ 48v = 130a input???
So if you want the highest voltage for the least voltage drop/smallest wire then you would have to do 5s4p = 5000w and then 3s for the remaining 750w??? I was thinking run the strings into a solar combiner but how does 3 panels 140v paralleled onto 5 panels 228v work? Is that possible or should I get a controller to handle 5 more panels. I have 50 panels. So if I do 5s4p that leaves 10 panels unused.
Make a series string of panels as close to 250V VOC AS POSSIBLE. then copy it exactly to make a parallel string. You do not need a combiner box if the panels are less than 10 years old, they all have diodes to prevent reverse charging. Instead of the combiner box use a branch connector. It joins two MC4 into one.