What is an EV Charging Curve and Why You Shouldn't DC Fast Charge Beyond 80%


Electric vehicles (EVs) have taken the world by storm in recent years, offering a cleaner and more sustainable mode of transportation. As EV adoption continues to rise, so does the need for efficient and effective charging solutions. One crucial aspect of EV charging that often goes unnoticed is the charging curve, specifically the practice of not DC fast charging beyond 80%. In this article, we'll explore what an EV charging curve is, why you shouldn't DC fast charge beyond 80%, and how this knowledge can benefit both you and your electric vehicle.

Understanding the EV Charging Curve

Before diving into the 80% rule, let's break down what the EV charging curve actually is. An EV charging curve represents how an electric vehicle's battery charges over time. It illustrates the relationship between the state of charge (SoC) and the charging power or rate. Typically, this curve is not linear; instead, it shows that charging speed varies during the charging process.

In simple terms, when you plug your EV into a charger, it charges rapidly from empty to about 80% SoC. After reaching this point, the charging speed begins to decrease significantly. This phenomenon occurs due to various factors, including battery chemistry, temperature, and safety considerations.

The 80% Rule: Why You Shouldn't DC Fast Charge Beyond It

Battery Longevity: One of the primary reasons to avoid charging your EV beyond 80% with DC fast chargers is to prolong the life of your battery. Lithium-ion batteries, which are commonly used in EVs, degrade faster at higher states of charge. Charging your battery to 100% repeatedly can significantly reduce its lifespan over time. By stopping at 80%, you can mitigate this degradation and enjoy a longer-lasting battery.

Charging Efficiency: As you approach the upper limit of your battery's capacity, the charging process becomes less efficient. The energy conversion and storage become less effective, resulting in more energy loss as heat. Stopping at 80% ensures that you get the most efficient use of your charging time and energy.

Safety: Charging to 100% capacity, especially at high power rates, can generate more heat within the battery, potentially leading to safety concerns. Heat is a common enemy of battery health, and by staying below 80%, you reduce the risk of overheating and related safety issues.

Time and Convenience: The last 20% of charging takes significantly longer compared to the initial 80%. This means that while you might achieve an 80% charge relatively quickly, pushing for that extra 20% can be a time-consuming endeavor. If you're on a road trip or in a hurry, stopping at 80% can be a practical decision.

How to Implement the 80% Rule

Implementing the 80% rule is quite straightforward:

Set Charging Limit: Many modern EVs come equipped with the option to set a maximum charging limit through their user interface. You can typically find this setting in your vehicle's charging menu.

Use Charging Apps: Charging apps or platforms often allow you to set a desired charging limit. These apps are especially useful if you're using public charging stations.

Plan Your Charging: If you're on a long trip and using DC fast chargers, plan your stops strategically. Aim to charge your battery to around 80% at each stop to maximize your time on the road while maintaining battery health.


Understanding the EV charging curve and the importance of not DC fast charging beyond 80% is vital for maximizing the lifespan of your electric vehicle's battery. By following this rule, you can enjoy a longer-lasting, more efficient, and safer battery while minimizing the time spent at charging stations. It's a win-win situation for both you and the environment, ensuring that your EV journey remains smooth and sustainable for years to come.

Previous Post Next Post

Contact Form