Defcon 4 - warning

[Pac0]

This is the doc of the sizing tool:

[Halfcrazy]

Pac0
So these 2 classics are on separate PV arrays and everything right? Common battery but separate arrays? I think it may be time to get ahold of Mat and schedule a trip to MidNite for that one. I would email or call Mat at Midnite for that. mat@midnitesolar.com

Ryan

[Vic]

Thanks Pac0 for showing the MidNite String Calculator output.

That output data shows that the Classic is just barely below its absolute maximum power output rating by 13 watts.

As I read your posts,  you got the second Classic 150 so you could divide the PV array into two equal arrays,   BUT,  because of the issue with one of the Classics,  you are still running this entire array on a single Classic.

When I asked MidNite about running a single Classic 150 at about full output on a 48 V system,  was encouraged to divide the array to divide the stress between the two CCs.  So,  IMHO,  it is a very good idea to not run any CC at or very,  very near its MAXimum.

Personally,  I wonder about reducing the output current setting on this single Classic until you get the issue with the other one gets resolved.  Perhaps setting it to 60 - 65 Amps would help SOME,  although the reduction in current from the array,  when it has maximum sun will raise the Vin somewhat,  which will reduce efficiency a bit ...   Just my thinking out loud.  Good Luck,   Vic

[Pac0]

Ryan Thank You, I will contact Mat... (for the other question see below)

Vic
I agree with your comments. The initial idea was this, two separate arrays, but when the Classic failed the first time I just had installed 3x3 = 1700Wp running. More below the maximum specs. Because the failure and the impossibility of have installed two independent sections of 1140Wp (in the future up to 1700Wp) I tried to add a fourth string with the new MidNite, until the first will return from the service. The problem that  I have explained before, has put me back to the begining again.

Thank you all for your time