Bypass diodes were designed for solar panels back when most solar arrays were constructed by feeding about a dozen series connected panels onto a grid-tied inverter. The purpose of the diodes is to improve the way a series connected array performs under partial shade conditions. When one cell or row of cells is shaded, the diode across that shaded section bypasses the underperforming cells, allowing the panel to maintain the same current as the other panels in the string. By maintaining the same current, the shaded cell(s), column(s), row(s) or panel(s) to not reduce the output current of unshaded panels.