Types of conventional current charging techniques 1. A constant current charger supplies a very low current so charging time is high, It is a simple design and low cost . Also, it is called "Trickle Charger", It not used for all battery. It hasn't any protective circuit which can avoid a battery against Overcharging. 2. Fast charging concept is to reduce a charging time of a battery with supplies a large current to battery. It consists with a circuit which disconnect a battery to supply after fully charge, also monitor a temperature at time of charging. But these kinds of charger have a limitation that if we use continuously, it will reduce a battery life, increase an internal resistance by formation of metallic crystal and charging by large current. 3. Constant current Constant voltage charger techniques battery receives a constant current until voltage reaches it predefine value. At this point charging voltage held constant until the charging current become zero. It has a same negative effect like fast charging techniques