Solar cell battery charging circuit - includes shunt with parallel sets of cells, one in series with bimetal switch

摘要

The charging circuit uses photo voltaic converters such as solar cells and includes two sets of cells (1,2) in parallel, with one set (2) in series with a thermally operated bimetallic strip (5). These are in series with a blocking diode (3) connected to the accumulator (4). Also in parallel with the cells is a shunt controller (9). This has one path formed by a shunt resistance (8) in series with a transistor (7), preceding the diode and a parallel path formed by the controller (6), following the diode. The shunt controller bypasses current from the battery as it becomes charged, and the temperature of the shunt resistance (8) increases as the current flow through it increases. This temperature increase operates the bimetallic switch (5) so that the current flow in the circuit is regulated.