Does Fast Charging Affect EV Battery Life?

Fast charging and battery life

EV technology has come a long way, and with it, the way electric cars are “refuelled”. Fast charging has become a popular option, offering the convenience of charging EVs significantly faster and safer than a standard 3-pin socket.

But this convenience brings up an important question: Does fast charging reduce EV battery life? We’ll look into the effects of fast charging and other types of charging, and whether it poses any risks to the longevity of EV batteries.

What is fast charging?

Fast charging refers to chargepoints rated between 7kW and 22kW. This is typically found in homes, which provide the electricity via alternating current (AC). However, EV batteries only store direct current (DC) energy, so fast (i.e. AC) charging has to be converted via a converter in the car. It’s this extra step that makes AC fast charging slower than DC (i.e. rapid) charging.

Rapid chargers are growing in popularity, with more appearing in the public charging network every year, because they charge much faster. For example, a 22kw charger will recharge a 60kWh battery in around three hours while a 150kW rapid charger can do the same in just under 30 minutes.

However, the lightning-fast speed of rapid chargers comes at a premium, and they tend to cost more than other public or home charging options. Because of this, it’s recommended to use fast charging for your everyday needs and tap into rapid charging whenever you need to quickly recharge to continue a journey and time is of the essence.

Want to learn more about different charging types? View our guide on EV chargers, connectors and speeds.

The effects of fast charging on EV batteries

Fast charging of up to 22kW has no detrimental effect on EV batteries, given other good charging habits are followed. To maintain a healthy battery, keep your electric car between 20 and 80% and out of extremely cold or hot temperatures.

However, frequent use of faster rapid charging has been shown to slightly increase the rate of battery degradation. A study testing two Nissan Leafs showed that exclusive DC rapid charging increased the rate of degradation by 16% when compared to AC fast charging.

The high voltage and current in rapid charging subject EV batteries to increased strain. Over time, this can wear them down quicker than fast charging would. Degradation reduces the battery’s capacity to hold charge, meaning you will run out of power faster than you used to when the battery was new.

Tips for preserving battery life while using rapid charging

For EV owners looking to maximise the lifespan of their batteries while using rapid charging occasionally, here are some top tips to follow:

• Monitor battery temperature – A high battery temperature strains the lithium-ion cells. The high voltage and current during rapid charging generate heat, which is normally controlled by the car’s battery management system. If this is faulty, you could see temperatures rise to detrimental levels, so it’s worth keeping an eye on it from time to time.

• Prioritise fast charging – Try to use fast charging as much as possible, like when parked at home overnight or at work. Reducing the frequency of rapid charging will help you maintain good battery health.

• Don’t overcharge – Charge up to 80% and then unplug your EV. Once your battery hits this number, charging slows down significantly, which removes the key benefit of rapid charging – its speed. Constant charging above 80% can harm the health of the lithium-ion battery.