A photovoltaic connection system for maximum current output and heat dissipation properties. The connection system includes a connection box with improved heat transfer capability to permit higher current output capacity. Diodes are surface-mounted on a printed circuit board inside of the connection box. An optional metal plate may be mounted inside the cover plate of the connection box as a heat sink for dissipating heat from the diodes. The metal in the plate has good thermal transfer characteristics, e.g., copper or aluminum.