Connected between a battery and dump load. Diversion Charge Controllers are typically used when the charging source cannot be disconnected from the battery, such as wind generators or hydroelectric chargers for off the grid electricity.
Diversion controllers do not cut off current from the charging source at all. When the battery charges to the maximum set voltage, the diversion controller connects a “dump load”such as ceramic air heating resistors or water heating elements to the battery to dissipate the energy coming from the charging source.
The controller adjusts its consumption rate to offset the excess charging exactly, and keep the battery voltage at, and never exceeding, the preset maximum voltage. If you use a windmill for off grid living that does not have its own charge control, or use hydroelectric generating, a diversion control must be used, since those generators can be damaged if their charge is not absorbed in the batteries at all times.
One diversion control handles a combination of solar, hydro and wind, so long as the total amps charge from all of them taken together is within its amp capacity.