Diversion Load Information
In most hydroelectric and wind-powered battery charging systems, the charging source cannot be disconnected from the batteries while running without the possibility of damaging them from over-reving. The typical way to regulate battery charging voltage with this type of generating system is to use a “load diversion” type charge controller. The Morningstar TS45 and TS60 and the Xantrex C-35, C-40 and C-60 can be configured for this mode of charge control. A diversion-type charge control also may be used in a PV system. If the array is much larger than necessary to charge the battery, excess power can be used to heat water by using a water heating diversion load. In operation, when battery voltage reaches the full charge setting in the charge control, it begins to divert excess power to the diversion load. The controller uses pulse width modulation or a relay to divert the excess power to the load or turn the power on and off to keep the battery voltage from rising further. To determine wattage of these diversion loads at other voltages, use Ohm’s Law formula: Voltage = Amps x Ohms The critical requirements are that the diversion load can dissipate more watts than the charging source can deliver, and that the maximum amperage that the load can draw is smaller than the maximum diversion rating of the charge control. Order one or more loads with a total current (amps) draw greater than your charging system’s maximum output, but no more than the maximum power rating of the charge control in the diversion mode. We recommend that you do not use a load that draws more than 75 percent of the maximum rating of the charge controller. For example, if the charging source can deliver 20 amps at 24 volts, use a 30 amp diversion load with a 40 amp or larger charge controller.