Xylem Ai1 Series Quick Start Manual page 21

While the categorization based on Sunshine Duration or detailed calculation for ESH may be used, consideration
should be given to localized shading and platform movement. Additional sensors may require the Ai1-36W model.
Vertical Panel Angle Considerations
The solar panels on the Ai1 are mounted vertically to allow top and bottom mounting options, to suit the widest
variety of locations (including higher latitudes) and to maximise self-cleaning. Solar panel power generation is
specified with incoming solar radiation at 1,000W/m
generation must be de-rated to allow non-perpendicular incoming energy. With fixed installations, winter sunshine
is maximised by orientating the panel South (in the Northern hemisphere, or North in the Southern hemisphere).
For a station installation at a latitude of 27.5°N, the panel would point South, at an angle of 50° (27.5° + 23.5° for the
optimum declination at the winter solstice). For vertical panels in a fixed location, the panels are to be orientated
East / West for morning and afternoon charging. In this arrangement, the panels must be de-rated by approximately
24%. The 2x9W panel arrangement is as effective as an optimum mounting for a single 6.8W panel. The
performance is demonstrated in Figure 3.
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Figure 20 - Power generation from optimum angle panels and vertical East/West (E/W) panels
Power Generation (W.Hr)
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2
perpendicular to the panel face. The solar panel power
9:36 14:24
Optimum E/W
19:12 0:00