Different Types of charge charge controllers There areseveral different basic types of charge controllers, the first being the seriescycling controller which is probably the simplest; the series cycling controllerprohibits overcharging of your batteries simply by turning your solar panel'scurrent off and on based on the battery voltage.

       If the battery voltage is to nearly full charge,a mechanical relay on the controller shuts off the charge.
When the battery voltage begins to fall and getslow enough, the charge controller kicks back in.
The constant voltage charge controller is basedon a three-stage method which offers more precise control than a series cyclingcontroller, giving you the maximum charging power possible on any given day.
       The constant voltage controller goes throughbulk charge first, which allows the power to go straight from the solar panelsto the batteries until they are charged.
The second stage is called the absorption stagewhich holds the maximum battery voltage by reducing the charge current.
       Float charge is the third stage and occurs whenthe battery voltage is reduced once the charge is complete.
       The constant voltage charge controller avoidsexcessive evaporation of battery water, thus extending the life of yourexpensive batteries.

       If you are using sealed, AGM or gel batteries,the three-stage constant voltage controller would be the best, safest method ofcharging your system.
Finally, a diversion charge controller nevercuts off from the charging source; it charges the batteries to the maximum setvoltage, then the diversion control senses the voltage, causing it to absorbthe excess current and off-setting the excess charge.

       If you are using wind turbines or hydroelectricenergy which do not have their own charge controller, then you must use adiversion controller, as these types of power generators can be damaged whentheir charge is not being absorbed into the batteries at all times.