Constant Voltage Charging (CV)
This is a simple method where a constant voltage is applied to the battery terminals. As the battery charges, the current gradually decreases. Once the battery reaches its full capacity, the charging process stops or enters a trickle charge mode. This method is commonly used for lead-acid batteries and some types of lithium-ion batteries. A constant voltage battery charger is a DC power supply which basically made up from a step-down transformer from the mains with a rectifier that provides the DC voltage which ultimately charges the battery. These forms of charging can be commonly found in inexpensive vehicle battery chargers. Backup batteries and car batteries, usually use lead-acid cells which requires constant voltage chargers. On the other hand, a constant voltage system is used with lithium-ion batteries. However, lithium-ion constant voltage systems usually consist of added circuitry which acts as a protection layer for the battery and the operator.
