A typical solar module has three such bypass diodes. In the past, Schottky diodes were generally used for this. However, the voltage drop at them is relatively high at 0.5 to 0.7 volts. This equates to a power dissipation of up to seven watts per diode in sunlight; in total up to 21 watts per solar module.
“In addition to the losses when operating these bypass diodes, there are also problems with heat dissipation in the case of the plasticjunction boxes” continues Rene Battistutti. “The high temperatures in the junction boxes lead to rapid ageing of the components and to additional thermal stress on the panel foils.” The result is more rapid ageing and thermal drifting of the solar cells in front of the junction box. The effect is simply intensified.
Modern solar modules can generate currents of almost 10 A under standardised test conditions (1000 W/m², 25 °C). Under actual operating conditions, they can sometimes be significantly higher.
“The e.ISP technologyis equipped with intelligent, highly efficient control electronics which generate 10 times less loss: 2.85 watts instead of 21 watts, like with standard diodes.” The system operator gets up to 18 watts more energy from the shaded photovoltaic module. “A factor which significantly increases system profitability”, says Battistutti emphatically.