Electric vehicles (EVs) have become increasingly popular in recent years, offering a cleaner and more sustainable mode of transportation. However, the performance of an EV relies heavily on its battery, which is susceptible to degradation over time. While manufacturers typically strive to increase the battery capacity to improve the range of an EV, the “EV 80% rule” suggests that Charging the EV to about 80% will maintain optimal battery performance and life over time.

Why is maintaining 80% battery power the best choice for EVs

What is the EV 80% rule?

The EV 80% rule refers to designing the battery capacity of electric vehicles to be around 80% of its maximum capacity to achieve optimal performance and lifespan. This is because charging and discharging become more difficult when the battery reaches its maximum capacity, which accelerates battery aging. In the 80% range of battery capacity, charging and discharging rates are slower, and battery lifespan is longer. Additionally, within this capacity range, battery safety is better because internal temperatures during charging and discharging are lower.

Why is 80% battery capacity the optimal choice?

Charging is not linear. Instead of batteries taking in energy at a constant, predictable rate, the rate changes based on myriad variables, though most notably the battery’s state of charge. The fuller the battery is, the slower it absorbs energy.

When it’s time to charge, it’s often wiser to stop at 80% and then get back on the road instead of waiting for the battery to fill up. Doing so maximizes your use of time. If your EV has 300 miles of range when fully juiced up, it can go about 240 miles with an 80% state of charge. You’ll stop and power up before hitting zero miles, but let’s keep things simple and say 240. If the 0-to-80% recharge time is 40 minutes, you can hit the road in less than half an hour, which is not too bad. If you want to replenish the battery fully, it could take 90 minutes to go from 80 to 100%. In the time it took to gain that extra range, you could be a hundred miles or more down the road and near another charger. That’s why stopping at 80% usually makes the most sense, though that is something you have to determine. Of course, there are instances where you’ll want to wait longer to hit 100%. There may be huge distances between DC fast chargers, and you need every range you can get. It could be the dead of winter, and you’re worried about reaching your destination – you’ve got range anxiety.

Although it’s commonly believed that rules are meant to be broken, when it comes to electric vehicle (EV) battery life, it’s advisable to charge to a lower percentage for optimal long-term performance. This doesn’t mean that charging to 100% is prohibited, but for those who plan on keeping their EV for many years, following this practice is akin to changing engine oil more frequently than the manufacturer’s recommendation in a traditional vehicle. It’s a good idea that can help extend the battery life of your EV.

By now, you should better understand the significance of 80% . Charging past this point using DC fast charging can result in a significant slowdown, and to ensure optimal battery longevity, it’s recommended that you limit your charging to approximately 80% unless additional range is necessary. Keeping this in mind can help you maximize the lifespan of your EV’s battery.