The Differences Between Fast Charging and Slow Charging for EV Chargers

Fast charging and slow charging are relative concepts. Generally, fast charging refers to high-power DC charging, which can charge the battery to 80% capacity in about half an hour. Slow charging, on the other hand, refers to AC charging, which typically takes 6-8 hours to complete.The charging speed of electric vehicles is closely related to the charger's power, the battery's charging characteristics, and temperature.

 With current battery technology, even with fast charging, it still takes about 30 minutes to reach 80% capacity. After reaching 80%, the charging current must be reduced to protect the battery, making it take a long time to reach 100%. Additionally, in colder winter temperatures, the required charging current decreases, further extending the charging time.

A vehicle may have two charging ports because there are two charging modes: constant voltage and constant current. Generally, a combination of constant current and constant voltage is used, which results in higher charging efficiency. Fast charging is caused by different charging voltages and currents, with higher currents leading to faster charging. When the battery is nearly full, it switches to constant voltage charging to prevent overcharging and protect the battery.

Both plug-in hybrid vehicles and pure electric vehicles are equipped with on-board chargers, allowing them to charge directly from a 220V power outlet. This method is typically used for emergency charging and is the slowest. The so-called "flying line charging" (where a cable is run from a 220V outlet in a high-rise building to charge the vehicle) is not recommended due to significant safety hazards.

For home use, there are two types of on-board plugs corresponding to 220V power outlets: 10A and 16A. Different models come with different plugs, some with 10A and others with 16A. The 10A plug is the same specification as household appliances and has smaller prongs. The 16A plug has larger prongs, similar in size to home outlets, making it less convenient to use. If your car is equipped with a 16A on-board charger, it is recommended to purchase an adapter for easier use.

How to Distinguish Between Fast and Slow Chargers

First, the fast and slow charging ports on electric vehicles correspond to DC and AC interfaces, respectively. Generally, fast charging ports have 5 pins, while slow charging ports have 7 pins. Additionally, the charging cables can help identify them, as fast charging cables are thicker. However, some electric vehicles may only have one charging port due to considerations like cost and battery capacity.

Fast charging offers quicker charging speeds but requires more complex infrastructure and higher costs. Fast chargers typically use DC power (derived from AC power from the grid) and require additional fast-charging equipment. They are more suitable for mid-journey top-ups but are not practical for all households, hence the inclusion of slow charging functionality in vehicles.

Slow charging uses the vehicle's built-in charging system and is beneficial for battery health, allowing it to charge to full capacity. Slow charging stations are simpler to build, requiring only a sufficient power supply without the need for additional high-current charging equipment, making them more accessible.