18kpv Solar panel wiring question

[tmprof]

I am currently installing 12 SEG 460W bi-facials . I was wondering if this would be ok to run all off the #1MPPT on the 18k? I live in Houston so the temp doesn't get much below freezing.

Panel info:
VOC - 41.52
ISC(A) - 13.96
Vmp(V) - 34.48
Imp(A) - 13.34

Using online calculators:

All Panels wired in Series
Max Power - 5519.56W
Voltage - 413.76
Amps - 13.34

All Panels wired in Parallel
Max Power - 5519.56
Voltage - 34.48V
Amps - 160.08

Using the 6s2p
Max power - 5519.56
Voltage - 206.88V
Amps - 26.68

It seems the 6s2p will have too much amperage for the single MPPT 1. I assume it's safe to just run them all in a series?

Thanks for your help.
-Troy

 

[pvgirl]

Based on the temp coefficients in the data sheet for SEG YUKON Series SEG-460-BMB-TB(assuming these are your solar panels) the open circuit voltage at -40 F or C is going to be 586 volts which is within specs, so all in series will be OK. Open circuit voltage at the coldest temperature is the big do not exceed value in solar string design as this can lead to permanent damage to your inverter.

 

[tmprof]

I do have a 25 amp/1000v DC breaker on this string before it comes into the inverter just in case. Thanks so much for the help!
-Troy

 

[Cmy]

On May 14 James from Signature wrote on EG4 18 string size and the newer, higher amp, M10 panels.

"Canadian solar 540W m10
This is a 13Amp panel, so 1x string on the small inputs and 2x on the large (26A vs 25 is safely under the 1.2 x clipping recommendations)
That leaves us with 4 strings of panels at 49VOC, the max string length is 11 in texas and may be 10 in colder places, let’s go with 10
4x10x540 = 21.6kW of PV.

I running voltage is 400v then total amps of 13+13+25=51A x 400v =20400 dc watts utilized, above the 18k needed for max utilization.
Note the 410w class solarever and others coming soon are in this range too."

 

[tmprof]

I'm not sure I understand. Are you saying 12 is too many for mppt1?

 

[Cmy]

Good question for Signature Solar, I just copied what they posted. But if 10 for colder areas than Texas, 11 in Texas, then how many for areas that seldom freeze like Tucson and Tampa? As mentioned earlier, heat reduces panel output while cold increases it. If a planned string has a reserve, does it cover experienced cold in your area? I like the SEG 460s, but while James was comfortable with 26 amps for a 25 amp MPPT, is 27.88 amps still OK. I know, within the 1.2 allowance but why not have a 'do not exceed' 30 amp limit? Fun times sorting this all out.