I was a bit scared to take my entire setup into the wild but it was worth it. The first real test in a harsh environment was a great success: a week in the Black Rock desert was noting but fun with no failure or downtime. During that last week of August we experienced a heavy rainfall with hail, dust storms and torching temperatures.
The solar controller was part of a setup described here. It was mounted outside in a somewhat shaded area to prevent direct sunlight onto its enclosure. Temperatures in the Nevada desert can climb really high and the recorded maximum for that week was 49.8°C (122°F)!
122°F desert heat
This mean a lot of ‘stress’ for all the parts: batteries, inverter, and controller.With higher temperatures you also see less efficiency mostly due to increased resistance in cables and the solar panels. If you look at the peak energy chart you can see the spike on the day with the rainfall (3rd).
The solar array produced 490 Watt peak power which is a stunning 95% of the rating for the STC value (107% of the PTC value).
STC in an acronym for Factory Standard Test Conditions, which is 1,000 watts per square meter solar irradiance, 1.5 Air Mass and 77 degrees Fahrenheit cell temperature. PTC is an acronym for Photo Voltaic USA Test Conditions, which were developed at the PV USA test site at the University of California Davis. The PTC rating represents a more real life condition of 1,000 watts per square meter solar irradiance, 1.5 Air Mass, 68 degrees Fahrenheit ambient temperature at 33 feet above ground level and wind speed of 1 meter per second. More in-depth info on this can be found here.
Average of 1500 Wh energy consumption per day
The Energy statistics chart shows the energy consumption vs. production – both are really close. This can mean a really nicely balanced system. The SOC chart below will also support this finding. The SOC values were recorded at day-dusk and night-dawn transition and will therefor not go up to 100%. SOC was not recorded as a daily maximum value and by dusk some energy was already used up. The discharge of the batteries bottomed out at 53% by the end of the night. This was leaving a solid safety buffer for a future expansion of the system.
According to the NREL PVWatts calculator the average available power per day in Gerlach, NV for the used solar array should be closer to 2750 Wh. This means there is room for expansion for the next years.
Recommended also: Solar camp power at Burning Man