There are several types of ev chargers

Electric vehicle chargers can be categorized into the following types:

1. Three-Stage Charger
   This is the most commonly used type in the electric vehicle industry. The charging process consists of three stages: the constant current stage, the constant voltage stage, and the trickle charge stage. From an electronics perspective, these correspond to the current-limiting stage, the high constant voltage stage, and the low constant voltage stage. In most chargers, the first two stages are indicated by a red light, which turns green during the third stage. The transition between stages is determined by the charging current.

2. On-Board Charger (OBC)
   Also known as an AC charger, this charger is installed inside the electric vehicle and connects to an AC power source through a socket and cable, operating on either single-phase or three-phase AC power. The advantage of this type is that charging can be done wherever an AC socket is available. However, due to space constraints within the vehicle, the power output is relatively low, resulting in lower charging currents and longer charging times.

   

3. Negative Pulse Charger
   Originating from fast-charging research for lead-acid batteries, this charger operates through a cyclic process: high-current pulse charging, temporarily disconnecting the charging circuit, briefly discharging the battery, stopping the discharge, reconnecting the charging circuit, and repeating the cycle. Instead of fully disconnecting the circuit during charging, a small resistor is used for momentary discharge, which helps protect the power conversion components of the charger. This method is claimed to extend battery lifespan.

Among these types, the on-board charger is considered essential for all electric vehicles. Even electric vehicles that primarily rely on battery swapping are typically equipped with an OBC. For EV users, understanding the characteristics of different charger types can help them choose the most suitable charging method, ensuring vehicle reliability and battery longevity.