Hello,
I started out small with my off the grid array and slowly added on as time, need and money warranted expansion. I now have seven 12 volt panels:
3 Evergreen 115
2 Sun 205 (just added)
2 BP 50
All are now mounted to a pole mount and will feed into a Midnite combiner box which in turn is regulated by an Outback Flexmax 60 that charges my 12 volt battery bank.
My question is.....I would like to run this array at or above 36 volts in order to minimize loss over the 80' to my home. What I am thinking is the problem is installing breakers on varied sets of panels due to their different amperage outputs. I guess what I am asking is what do you think is the most advantageous route to safely wiring this convoluted number of panels together. Is there a way to fuse the panels independently inside a combiner box and therefore increasing the voltage while safely fusing them into three different groups?
The panel specifics are needed, but I have a hunch that this will not work too well.
Evergreen120
Maximum Power -Pp(Watts) 120
Voltage at Maximum Power -Vmp (Volts) 17.6
Current at Maximum Power - Imp (Amps) 6.82
Open Circuit Voltage -Voc (Volts) 21.5
Short Circuit Current - Isc (Amps) 7.68
Cells 72
Max Series Fuse (Amps) 15
BP SX 50
Voltage at Pmax 16.8V
Current at Pmax (lmp) 2.97A
Warranted minimum Pmax 45w
Short-circuit current (Isc) 3.23A
Open-circuit voltage (Voc) 21.0V
Sun 205
PMPP Max 209.9w
Min 205w
UMPP 18.4v
IMPP 11.15a
VOC 23.0
ISC 11.87a
Max Over current Protection is 30a
the only way i see this going together for a 36v pv system would be to place the 2 sun 205s in series, 2 of the evergreens in series, leaving you with the 2 bp 50s and a evergreen. parallel the 2 bp 50s and place them in series with the remaining evergreen. this won't work optimally, but it will work.
fuse/cb rating for the 2 evergreens in series is the same as 1 for they are in series making the current stay the same. 15a.
fuse/cb rating for the 2 suns in series are also the same as 1 as the current is still the same. 18a as shown here, http://www.sunelec.com/Specs/SUN/SUN-SV-T-190-195-200-205-HV.pdf i doubt you'll find one of that value so maybe use a 15a so the max reverse current is not possible.
the 2 parallel bp 50s in series with the evergreen shall still be similar in current as either one band totaled so go with the same 15a.
this is not an optimal arrangement as some mismatching is evident, but would be close enough for it to actually work as a 36v pv system together.
Thanks for the reply, I think this makes sense and may be my best option besides selling off the whole lot and purchasing a whole new setup-something that my pocketbook nor my ego could handle at this time.