Which DC disconnect switch to use for PV strings?

Still trying to design my off-grid system. I have 20 445W panels, arranged in 2 strings of 10 (2S5P), each feeding a Victron 150/85 SCC. Here are the specs I calculated for each string.

Rated PV Array Power 4450 Watts
Anticipated Array Power @ 40 C 4216 Watts
Rated PV Array Current 53.9 Amps
Battery Charging Current @ 57.6V 77.3 Amps
VMP (Maximum Power Point Voltage 82.6 Volts
VOC (Open Circuit Voltage) 98.2 Volts
VMP @ -10 C 92.8 Volts
VOC @ -10 C 107.4 Volts

Would this work? MNPV6-Disco http://www.midnitesolar.com/product...connecting&productCat_ID=26&sortOrder=2&act=p

Just looking quickly, I would suspect your maximum voltage, in a string of 10 445W panels in series, will probably far exceed the input capacity of 150v for the controller! You will see two blinking lights, telling you that you have exceeded the maximum rating, and are doing damage.
The Victron controller name tells you the maximum volts in>> 150, and the maximum amps out>> 85 amps at whatever battery voltage you are using.
When stringing the panels in series add volts, when going in parallel add amps.

I did think about the other way, paralleling the panels, but getting wire to carry that amperage? I think the limit on standard solar wiring is about 20amp over 30 metres, or similar? Most people string their panels in series to obtain higher voltage, and lower amperage, because high voltage/low amperage has less loss, more efficient; Victron controllers are also set up for higher voltage (I think they need 5 volts higher than battery system, to start charging (need to look that up).

What panels exactly are they? I found one panel rated at 445W and they have a Voc of 49.1V. Putting 10 in series would be 10 x 49.1V = 491V which far exceeds that controller.

dennisuello said:

Still trying to design my off-grid system. I have 20 445W panels, arranged in 2 strings of 10 (2S5P), each feeding a Victron 150/85 SCC.

Click to expand...

I think saying "2 strings of 10 panels" has caused some confusion.

You really have two strings of 2s5p, which should be fine for the Victron unit, but admittedly I didn't check the specs for the Victron or the DC disconnect.