Outback MPPT controller Help with Voc, Vpm, Ipm, Isc and nominal voltages.

Have you tried www.mcmaster.com (McMaster-Carr) ?

Thanks for the reply! Yes I would like to use a 48 V nominal setup with the sharp modules. I presume my calculations are correct then or you would have said so? But with the Sharps the #0 AWG cable required in my opinion is just too large to run 150 feet!
What about a 72 V nominal setup? The Wattsun AZ-225 Tracker can mount a maximum of 16 Sanyos and 16 Sharps. But with the sharp modules I wouldn't be able to add 2 more to make 18, so I have to minus 1 loosing 175W and have unused space on the Wattsun tracker, is this correct?
With regards to what you say about the Sanyos meant for a grid tie ... I thought connecting them to an MPPT step down controller was similar to an MPPT inverter setup. My main question was would all or any of these arrangements be suitable for an Outback MX60 or FLEXmax 80 and which would you advise in this case? If it's the FLEXmax 80 then why?
OK but I'm so sorry to say that I don't understand this statement about vmp but your help is much appreciated thanks.
Regards,
Simon.

James,

Thanks for the explanation I do appreciate it really but you don't answer ALL my questions ... Year well like I said I wouldn't consider a 48v nominal array with the Sharp 175s because if my calculations are correct the required 46.15mm2 cable size is just too large to run 150 feet.
What do you think about this configuration:
Modules: 16, Day4Energy 48 MC 190, 190 W STC, 24 Vpm, 7.9A Ipm, 29.7 Voc, 8.3A Isc
Array: Four  4-module series string, 3,040 W STC total, 96 Vmp
Wire Size: (150 x 31.6) / (2% x 96) x 1.1 = 27.16mm2, requires #2 AWG
What is the nominal voltage here with these four 4-module series strings?
MAX 150Voc at -1deg. to -10deg. is (29.7 x 4)x1.13 = 134.244 yes?
Once again your help is much appreciated.
Regards,
Simon.

Firstly thanks for the detailed reply! It's great to have someone to check my calculations and give support and advice and I thank you very much! You've certainly got me thinking. After contacting the met service here in the past 20 years the coldest temperature has been -8.7°C and the hottest 36°C.
The Day4Energy modules have 36.417 in. of #? AWG cable on the back and use Tyco Solarlok conections.

I have been using Appendix I and Appendix E in "Photovoltaic Power Systems and the National Electric Code: Suggested Practices" from the Southwest Technology Development Institute website here:
http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/PVnecSugPract.html
Also I don't have a copy of the 2008 NEC so I've only referenced the tables from the 2005 NEC I can view online here:
http://www.nfpa.org/freecodes/free_access_document.asp

If you could please check over the following calculations to make sure I'm on track then it would be much appreciated. I think what I'm really tying to figure out now is what type of direct burial cable I need from the PV combiner box to the controller or in other words whats it called, USE, UF, SE, XLP? and what temperature derating is used [NEC Table 310.16] to calculate the required AWG size for a 2% voltage drop?

Proposed PV Installation:
Modules: 16 Day4Energy 48 MC 190, 190 W STC, 24 Vpm, 7.9A Ipm, 29.7 Voc, 8.3A Isc
Array: Four  4-module series string, 3,040 W STC total, 96 Vmp
Wire Run: 45m (150 feet)!
Inverter: Xantrex SW3048E
Battery Bank: 16 Trojan T-105 flooded-cell @ 48 volts
Calculations:
The module short-circuit current is 8.3 amps and as stated above the array consists of 16 modules divided into four 4-module series strings, therefore each string short-circuit current is 8.3 amps.
CONTINUOUS CURRENT: 1.25 x 8.3 = 10.375 amps
80% OPERATION: 1.25 x 10.375 =  12.97 amps per module

All calculations are based on copper conductors.
The maximum estimated module operating temperature is 70°C therefore the cables must be temperature derated.
[NEC Table 310.16]
At an ambient temperature of 30°C the derating factor for USE (75°C Insulation) cable is 0.33 at 61-70°C.
At an ambient temperature of 30°C the derating factor for USE-2 (90°C Insulation) cable is 0.58 at 61-70°C.

Therefore what size cable would be used to exceed the required 10.375 amps per module string?
Cable 10 AWG USE (75°C Insulation) has an ampacity at 70°C of 11.55 amps (0.33 x 35)
Cable 10 AWG USE-2 (90°C Insulation) has an ampacity at 70°C of  23.2 amps (0.58 x 40)
Cable 12 AWG USE-2 (90°C Insulation) has an ampacity at 70°C of  17.4 amps (0.58 x 30)
Cable 14 AWG USE-2 (90°C Insulation) has an ampacity at 70°C of  14.5 amps (0.58 x 25)

The requirement of 156% for each overcurrent protection at the PV combiner box is 1.25 x 10.375 = 12.97 amps.

Therefore what size circuit breaker would be used for each four module strings to provide overcurrent protection for the conductors? 13 amps? 14 amps? 15 amps is the maximum stated on the Day4Energy modules and do these have a rating less than the derated cable ampacity?

The array (4 string circuits) short-circuit current is 4 x 8.3 = 33.2 amps.
CONTINUOUS CURRENT: 1.25 x 33.2 = 41.5 amps
80% OPERATION: 1.25 x 41.5 = 51.88 amps

Therefore the ampacity requirement for wire size from the PV combiner box to the controller is 4 x 10.375 = 41.5 amps.
I would like to use a direct burial cable for the 150 foot run. What type of cable is required, USE, UF, SE, XLP? I would prefer to use a 2 core with earth shield or 3 core, is this available? What temperature derating would you have to consider?
In this case then what size AWG cable would be required for a 2% voltage drop?

Once again you help is much appreciated thanks.
Regards,
Simon.