We're running our station from 2x 100W UBSCO mono-crystalline solar panels, 103cm x 67cm, collecting power at about 17% efficiency. These are attached to a custom-built extruded aluminum frame, mounted at a 22ºθ angle to the sun.
This angle was selected so as to optimize spring-summer-fall flying season usage, ignoring most winter sunlight hours when our club doesn't fly or need FLARM situational awareness coverage.
Our power management and distribution is based on Ubiquiti Networks' SunMAX SolarSwitch MPPT battery charge controller, Power over Ethernet distribution for our system components, 10/100Mbps ethernet switch, and per-port power scheduling via a web interface.
Here's Ubiquiti's diagram to illustrate a similar deployment to ours:
In our case, we're running 2X (two) Motomaster Nautilus Group 27 deep-cycle 12V batteries, with approximately 105AH of power each. On average seasonal charging (spring through fall) this should give us 2-3 weeks of run-time without any charging on our relay station. On average our whole system draws about 8-12W at 5VDC, and we can easily collect 8-15W on overcast and cloudy days.
