The efficiency of the photovoltaic energy conversion depends on the temperature significantly. We monitored the behavior of I–V characteristics of the PV cell based on monocrystalline silicon in temperature range with extreme limits from −170 °C to +100 °C. We have not yet found a similar measurement in this temperature interval. The temperature of PV modules without radiation concentration can reach values of −100 °C to +100 °C on the Earth's surface. The temperature range may be few wider in space. Changes of I–V characteristics and P–V characteristics are discussed in terms of the theory of solids. The open-circuit voltage dependence is approximately linear over a wide temperature range, but saturation occurs at temperatures around −150 °C, which is also explained in accordance with the theory of semiconductors. The decrease in energy conversion efficiency with increasing temperature has a value of about 0.5%/°C throughout the whole temperature range possible on the Earth's surface. If there are large changes in the temperature of the PV modules during operation of the PV system, the electrical voltage of the PV modules will also change considerably. In space applications, these fluctuations may be greater. This must be taken into account when designing PV systems (especially for deep space missions). For example, electronic inverters are sensitive to overvoltage or undervoltage.

There exist over 2 GW of photovoltaic (PV) systems in the Czech Republic, exposed to moderate continental climate. Although there exist many PV modules defects, thanks to the generally the same production year 2009, only some of them are usual at systems installed in Czech Republic. This work shows delamination failures that are frequent in moderate climate conditions. Special account is taken into edge delamination defect and its possible propagation in modules of standard construction. Combined PV panel and PV inverter failure is caused by edge delamination with water penetration and high string voltage. The electric discharge channel is created between the string of solar panels and the grounded PV panel frames. The result of the discharge channel created because of edge delamination is inverter switch- off and few months later total destruction of the inverter because of protective relay damage. The number of combined PV panel and PV inverter failures is increasing substantially after ninth year of operation of PV panels in moderate climate. Additional sealing of the PV panel frames by transparent polysiloxane gel reduced the number of combined PV panel and PV inverter failures very substantially.