Battery Charging, Trickle Charging onboard

 Basic charging circuit

 To charge the battery we have to give DC supply to the battery on a timely basis. As you know, ships use AC supply, so we have to convert AC to DC using a rectifier . Below showing the basic diagram of battery charger

 As it can be seen in the diagram AC is stepped down to the required voltage and then the AC is converted to DC with the help of a rectifier system which changes sinusoidal wave of AC to DC system. It is then connected to the battery terminal.

Trickle Charging

     When you charge a battery technically charging should stop when full battery voltage has reached. However , in that case, the battery starts self discharging due to its internal resistance. Some batteries like emergency batteries are required to be fully charged all the time. In order to keep it in a fully charged position, it is practice to keep a small current just enough to balance the discharge. This small current is the trickle current. A charging circuit is designed to maintain this trickle current once full battery voltage has reached.

 If the batteries are in standby mode, with the charging switches C closed and the Emergency load switches E open. The positions of these switches are held with the help of an electromagnetic coil against the spring tension. The electromagnetic coil gets its supply from the main power source available on the ship. As soon as there is a loss of main power, the electromagnetic coil loses its power and the batteries are connected to load switch E which gets disconnected from the charging switch C.