In recent years, active solders have made their way into use in solar panel manufacture. To understand where S-Bond solder alloys are being used one has to understand the solar panel construction. Solar panels consist of arrays of solar cells, soldered together. A solar cell consists of three basic elements, top contact, base and rear contact, as shown in Figure 1. From the back of each solar cell, electrical contact needs to be made between these surfaces to close the circuit and provide an electron path as photons emit electrons in the semiconductor polysilicon photovolatic (PV) cell which migrate to the back of the exposed cell surface, as illustrated.