[RE-wrenches] Max Insolation

[Larry Crutcher, Starlight Solar Power Systems]

Ray,

Regarding the PV power from Photowatt, did you put a load on the output/batttery to drop voltage to or below battery resting voltage? Doing so will force the controller to output the maximum power available. If you don't, then battery acceptance dictates the power being generated. Also, disconnect the PV module and try a short circuit test. Adjust for irradiance.

I have found the Daystar meter to be a reliable and useful tool. 

Larry Crutcher
Starlight Solar Power Systems
(928) 342-9103
www.starlightsolar.com




On Aug 29, 2012, at 11:26 AM, R Ray Walters wrote:

Hi All;

I was recently at a mountain top solar site (11,000 ft), doing some testing, and I measured insolation values that were averaging 1400w/m2, with a temporary peak (edge of cloud effect) that hit 1800w/m2.
Do I need to my meter recalibrated?  Its the Daystar, and seems to be accurate,  when we got some cloud cover, insolation dropped to 200-300 w/m2 as expected.

Interstingly the aging Photowatt 1000 modules were running at only about 60% of rated output current into a Blue Sky 3048 MPPT controller.  So I'm also wondering if I have faulty modules.  Back of module temps were about 95 deg F.
Any help on both the high insolation reading or Photowatt troubles would be great.

Thanks in Advance,

Ray Walters

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