If you power up your electric car, you might observe that you don’t always receive the quickest charging rate that your automaker or the charger promised you. On different days, you also might find out that you are getting different charging speeds. 

Why does it happen?

The answer is simple. Charging an electric vehicle is more similar to charging your phone than fuelling your vehicle at a gas station.

While every EV is different, here are five factors that affect charging speed:

The State of Charge (SoC) is an indicator of the amount of power left in your battery when you begin to charge it; it’s equivalent to a fuel gauge. 

When your SoC is low, it is much easier for electrons to fill up the “seats”; in contrast, when your SoC is high, it takes longer for the electrons to find an available spot, thus slowing down the charging process. 

Think of it as a movie theatre. When it’s empty, finding a seat is much simpler than when it’s full and you have to search for an opening and climb over people’s legs without spilling their popcorn. Similarly, the SoC of a battery affects the speed of the charging.

The temperature of your EV affects recharging speed

Generally, batteries need to be kept at a temperature that is neither too hot nor too cold. This is to protect the battery and maintain its health. An Electric Vehicle (EV) will have a Battery Management System (BMS) that is like the battery’s brain, which monitors the battery’s safety. Extreme temperatures can affect a battery’s life expectancy. 

Most EVs come with a thermal management system, which controls the temperature of the battery for it to stay at an optimum level. However, the outside weather can still influence the battery. If it is very hot or the battery has been charging for a long time and is heating up, the charging speed will be slower. Likewise, if it is freezing cold, the charging pace will also be slower.

Using your EV while recharging

If you stay in your car during fast charging, it is important to be aware that some of the energy that should be going to the battery is instead used up by cabin air conditioning, heating, lights, radio, and other accessories. Additionally, the thermal management system also utilizes some of the charging power to regulate the temperature of the battery. This is why it may seem like the kW display on the charger is a bit higher than what the in-dash displays show.

Battery deterioration

Over time, batteries can deteriorate and lose their charging capacity. As a rule of thumb, it is recommended to stop charging when the SoC reaches 80-85%. This not only prevents the battery from becoming too hot but also saves time as the charging rate decreases when the battery is close to being full.

Your vehicle’s current and voltage limits

Regardless of your EV’s charging capacity, it has a max rate of charge it can take in. This maximum charge rate (also known as the voltage limit) is set for the vehicle. For example, if the EV has a maximum charging speed of 7 kW and the charger can give out 22 kW, the EV will still only draw energy at the rate of 7 kW. The opposite is also true, if the EV is able to take 15 kW but the charger can only provide 7 kW, the car will again only draw energy at 7 kW.

Overall, there are many factors that can affect your EV recharging speed, from the type of charger you are using to the temperature of the battery.

If you enjoyed this post, don’t forget to check out our latest blog- How to pick the right EV for Yourself in UAE.