Solar Guppy, I notice that 2 of your inverters are running on relatively low voltage (285-295). I'm just curious because I now have the chance to do it right. Did you choose this for a reason other than size restrictions?
According to the Xantrex sizing tool I can go anywhere from 8 - 12 panels so I assumed I would want to go as high as possible.
Comments?
thanks

The East and West arrays are configured the same, they are 2 strings of 10 PW1650-155/165's, which are 24V nominal 155watt/165watt panels

This is about 3300 STC watts per inverter.

On any String inverter, the lower the operating voltage, the higher the efficiency, its about 1-1.5% better running at this voltage (VDC ~280's) than than (VDC~500's). Technically, it's called switching losses and they go up much faster with higher voltages than the current losses increase operating at a lower voltage. For ANY string inverter, running at near the minimum operational voltage will be the sweet spot.

The CEC site has all the inverter test data, you can look up all listed inverters and see this effect.

http://www.consumerenergycenter.org/erp ... index.html

For example, look at the PVP 3200

http://www.consumerenergycenter.org/erp ... PR3200.pdf

Or the Sunnyboy 3800

http://www.consumerenergycenter.org/erp ... 0U-240.pdf

Or the Xantrex GT3.8

http://www.consumerenergycenter.org/erp ... _GT3.8.pdf

In the real world, 1% is in the noise and configure your panels in the way the configuration wise best matches the power handling of the inverter and or the number of panels for your installation