Why is fast charging still so slow?

Have you encountered issues charging your car to its full capacity at a charging station? What are the reasons behind the slow fast charging?

1. A correct understanding of charging procedures

Before exploring the reasons behind slow fast charging, we need to establish a correct understating of charging. Besides the movement of plugging the charging connector into the charging port in the electric vehicle and the activation of the Battery Management System, there are some steps of communication between the charger and the EV.

  • ┬áCharging handshake: in this step, the charger will send the protocol version number to the car, and in return, the car will send the information about its own largest charging voltage to the charger.
  • Charging parameter configuration: the car will send the specification of its battery and the charger will send its largest charging output capacity to the EV. Then two sides will send they are ready for charging to each other.
  • Charging: BMS will tell the charger about its demand and condition and the charger will send charging conditions like output voltage, current, and so on. The charger will adjust output according to the demand of BMS.
  • Charging finished: BMS will send statistical data to the charger and the charger will finish charging.

fast charging

2. Correctly understand changes in charging speed

When you get the charging procedures, it is time to look at the charging speed of the EV charger.

The charging speed is not fixed. At the beginning of charging, the battery needs to be warmed up, so the charging speed is not very fast. But it will become faster and faster and then charge EVs at a fixed and relatively fast charging speed based on the demand of BMS. But when SOC reaches 50% to 60%, the charging speed declines. When the SOC reaches 80%, the charging speed will become slow charging to ensure charging safety and battery life. So, it is not sensible to wait for full charging because charging the last few percent of electricity costs too much time. With an AC EV charger at home to fully charge your car, you will save money and time as well.

3. Factors affecting charging speed

1) Voltage

We have heard about an 800V electric car, right? Correspondingly, the 800V car needs an 800V charger. When you find a charger with lower voltage, of course, you cannot fully take advantage of the charging capacity.

2) Power sharing adjustments

It involves dynamic load balancing. In terms of AC EV chargers installed at home, dynamic load balancing is needed to prevent EV chargers from taking up the power from other electric appliances. When it comes to DC charging stations, there is a power-sharing to avoid long-time queuing and rationally distribute power to different electric cars.

As we mentioned, if there is a 360kw charging station, the first car with lower SOC needs 150kW, the second 150Kw but there comes another car which will make the station distribute power again to a slower charging speed for the first and second car. Voltage architecture of EV

3) Environmental impact

The charging and discharging of the battery are influenced by temperature. When in winter, charging speed will become slower than usual. So, in northern China, there are fewer EVs than in the South. But why the prevalence of electric vehicles in Norway is so high? Because of their existing energy structure. And their electric vehicles use upgraded batteries to defend against the cold.

charging car


So, what determines the fast charging speed of electric vehicles? This is a question that requires comprehensive consideration. There is no single answer. The impact of “fast charging” speed cannot be attributed to one reason. The best solution is the continuous development of charging infrastructure so we can have more choices and not be confined to a certain area because of range anxiety. And this is not the effort of a single side: government, entrepreneur, and every individual. From the point of an individual, for a short distance commute, a BYD seagull with a home-use EV charger is a wonderful choice. Numerous single steps accumulate a giant leap in green mobility. We Bluesky look forward to cooperating with you to achieve the small step.

Update cookies preferences

Get a Quick Quote!


    Get a Quick Quote!