EV chargers are broadly categorized in 3 types of categories:
- AC or DC
- Smart or Non Smart
- Connector Based
Difference between AC and DC chargers
All Electric Vehicles run on batteries which are Direct Current (DC) and our grid or the electricity that comes to our homes and offices is Alternating Current (AC). Electricity needs to change from AC to DC to be able to charge an EV battery.
Most modern EVs come with an on board charger (AC to DC converter) to make it easier for us to charge EVs at home or at normal plug points. An AC charger is mainly responsible to make sure AC Electricity reaches the car in a safe manner. AC chargers have a lot of protections like under/ voltage protection, residual current protection, overcurrent protection. These protections are both for the EV and the humans that interact with the EV Charging Equipment. The actual charging is done by the EV’s on board AC to DC converter. AC chargers usually give low power to charge the EVs in the range of 3.3kw to 7.4 kw single phase or 11kw to 22kw 3 phase.
DC chargers on the other hand bypass the cars on board charger and charge the battery directly. DC chargers are much more powerful and can charge EV batteries in a fraction of the time it takes to charge from an AC charger. DC chargers are used more for commercial charging stations on places like highways where EVs need to be charged in a short period of time. DC chargers need special connections and approvals from utilities to install as they consume a significant amount of power. They also cost significantly more than AC chargers. For cars and buses DC chargers come in the range of 30 to 350kw.
Small DC chargers are also used to charge 2 and 3 wheelers. These chargers are much smaller and can range from a few hundred watts to 5kw. 2 and 3 wheelers do not have an onboard AC to DC converter on board to reduce weight and cost.
Difference between smart and non smart chargers
Most EVs come with simple chargers that can be plugged into a wall socket and the vehicle to charge the vehicle. These chargers are not connected to the internet and cannot be controlled through an app or used for commercial purposes. These are usually lower powered portable chargers that can be carried along. These chargers can also be used by anyone if left unattended.
Smart chargers are usually connected to the internet or directly to your phone using Wifi or 4G or Bluetooth. They can also be activated using simple Radio Frequency identification cards (RFID). For a consumer with a smart charger installed at home they can control their charger and charge their car at a certain time and for a certain time during the day, this helps them to make sure that the car charges when the utility prices are the lowest to help maintain charging costs low. These chargers are also used for commercial purposes and have built in energy meters to record consumption. Most charge point operators use OCPP servers and OCPP compatible chargers to manage their chargers. The users simply use an app to book the EV charger in advance and pay for the charging to a particular charger.