What am I missing? EG4 6500EX-48 array and wiring diagram

[MartyByrde]

Hi,

I am working on figuring out how to set up my solar arrays for the EG4 6500EX. Using SanTan Solar T Series 250W Snail Trails panels. I used Midnight Solar to calculate each string:



I found that 4 strings in series joined at a combiner box seemed to be the only way I could get to the 4000w PV input for each of the two MPPTs in the EG4 6500EX. I would have 2 idential 4000w arrays. I calculated I could use 10AWG PV wire for each string and combine them into the Eco Source 4 String Combiner Box. Both combiner boxes and both solar arrays would be grounded to the same 10ft copper ground bar in between them.

Each combiner box output would first go through a Schneider DC Breaker | 60A 160VDC (I realize I have 15A on the diagram), then both feed into the IMO DC Disconnect Rooftop Isolator Switch.

What am I missing with this?

Thanks for any input!

 

[Subdood]

Unless I'm misunderstanding you, if you put four of these 4 panel strings in parallel, you're going to exceed the max input current rating of each PV input of 18A. Total current would be 4 x 8.3A or 33.2A.

Why not put 8 panels in series, and run two of those strings in parallel to each PV input? Each PV input can handle 450V (500Voc) and 18A, or 4000W. Eight panels in series would give you 301V Voc, 242V Vmp and 8.3A Imp, for a total of 2009W. So, two parallel strings would be 301Voc, 242Vmp and 16.6A, and 4018W per PV input. Add another two strings of 8 panels in parallel for 4018W for the other PV input. You could then run all 4 of these strings thru the combiner box.

But, bear in mind, you'd need a different combiner box and a different DC disconnect to handle the extra voltage and current. But this way, you'd only need one combiner box, instead of two as you proposed. You'd still need two IMO DC disconnect switches.

I'm not sure about your grounding of the arrays, are you talking about a ground mount or rooftop mount? Either way, I don't know enough about that to say if it's safe to use two grounding posts.

 

[Rubicon_Traveler]

This is exactly what I'm planning. How did it go, how's it going OP?