[RE-wrenches] overfeed 7kW gridtie inverter or drop a mod per string?

[David Brearley]

Is using the SMA SB 8000US out of the question?

http://www.sma-america.com/en/products/solar-inverters/sunny-boy/sunny-boy-5
000us-6000us-7000us-8000us.html


On 4/19/10 3:37 PM, "Jim MacDonald" <jmac at solaresystems.com> wrote:

> For a straight grid-tie system@ 10 degree tilt, 180 azimuth, zero/little
> shade, NYC avg 4.29 kWh/m²/day.
>  
> Feed an SMA7000 with (3) strings of 11 Suntech STP275¹s [9.075 kWdc]
> Or
> Do strings of 10, so itd be 8.250 kWdc into the 7 kWac inverter.
>  
> Strings of 11= 491.7 Voc; 386 Vmp
> Strings of 10= 447 Voc; 351 Vmp
>  
> The tradeoff would be power clipping at/around noon in the sunny months in the
> 9.075 kW scenario;
> Inverter sleeping late every morning and retiring early in the evenings in the
> lowered voltage scenario.
>  
> Trying to figure out which would yield more kWh at the end of the year.
>  
> Any ideas appreciated,
> thanks
>  
>  
>  
>  
> Jim MacDonald
> Solar Energy Systems, LLC
> Brooklyn, NY 11222
> www.solarEsystems.com <http://www.solaresystems.com/>
>  
> 
> 
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David Brearley, Senior Technical Editor
SolarPro magazine 
NABCEP Certified PV Installer 
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