should i charge my ev to 80 or 90

Why Charging Your EV to 80% or 90% Matters

Electric vehicles (EVs) have rapidly gained popularity in recent years, offering a greener and more sustainable option for personal transportation. One common question among EV owners is how much they should charge their vehicles. The charging process plays a crucial role in maximizing the battery life and overall efficiency of an EV. In this article, we will dive into the debate of whether you should charge your EV to 80% or 90% and explore the factors that influence this decision.

The Impact of Charging Levels on Battery Life

Maximizing the longevity of the battery pack is a top concern for EV owners. Lithium-ion batteries are the most common type used in EVs, and their lifespan is influenced by various factors, including the state of charge (SoC). Keeping your battery between 20% and 80% capacity is often recommended for optimal longevity. However, the debate arises when considering whether to charge your EV to 80% or 90%.

Charging up to 80%:

Proponents of charging to 80% argue that it offers the best balance between battery lifespan and driving range. By avoiding the extremes of a full charge, you can reduce the strain on the battery, minimizing degradation over time. Additionally, charging to 80% ensures that you have a sufficient buffer for unforeseen situations or unexpected trips, providing a comfortable safety net.

Charging up to 90%:

On the other hand, supporters of a 90% charge believe that the slight reduction in battery lifespan is outweighed by the increased driving range it offers. By charging to a higher level, you can embark on longer trips without worrying about your battery level dropping too low, which can cause range anxiety, a common concern among EV owners.

The Role of Battery Chemistry

When deciding between an 80% or 90% charge, it's essential to consider your EV's battery chemistry. Different EV manufacturers use various types of lithium-ion batteries, each with its own characteristics and recommended charging levels.

1. Lithium Iron Phosphate (LiFePO4) batteries:

LiFePO4 batteries are known for their exceptional durability and safety. These batteries tend to have a slower capacity degradation rate, making them less susceptible to the negative effects of charging to higher levels. Therefore, owners of EVs equipped with LiFePO4 batteries may lean towards charging up to 90% without significant concerns about battery life.

2. Lithium Nickel Manganese Cobalt Oxide (NMC) batteries:

NMC batteries strike a balance between energy density and durability. While they offer a higher driving range, these batteries are more sensitive to higher SoCs. Charging up to 90% regularly with NMC batteries can lead to faster capacity degradation over time. Therefore, owners of EVs with NMC batteries may opt for an 80% charge to prioritize longevity.

The Impact of Charging Habits on Battery Degradation

Aside from the charging level, how you charge your EV can also influence battery degradation. Let's explore some factors that can affect your battery's lifespan:

1. Fast charging:

Fast charging, also known as DC fast charging, allows you to quickly replenish your battery's charge. However, frequent use of fast chargers can result in increased temperature rise and stress on the battery cells, accelerating degradation. If you often rely on fast charging, charging your EV to 80% may be a prudent choice to mitigate the strain on the battery.

2. High charging rates:

Charging your EV at high rates, whether it's using a Level 2 charger or a fast charger, can generate excess heat and contribute to battery wear. To minimize degradation, it is advisable to charge at a slower rate when possible, especially if you opt for a higher charging level like 90%.

The Effects of Temperature on Charging Decisions

Temperature is a crucial factor that affects both battery performance and degradation. Extreme temperatures, whether too high or too low, can impact the battery's lifespan and driving range. Here's how temperature comes into play when deciding between an 80% or 90% charge:

1. Hot climates:

In regions with hot climates, such as desert areas, a higher charging level like 90% can result in increased battery stress due to elevated temperatures. Consequently, opting for an 80% charge could help mitigate the cumulative effects of temperature and charging on the battery's degradation rate.

2. Cold climates:

Cold temperatures can cause the battery's chemical reactions to slow down, reducing its performance and available capacity. Charging your EV to a higher level, such as 90%, can provide a larger buffer to compensate for the decreased range in frigid conditions. However, it is worth noting that extremely cold temperatures can still impact battery efficiency regardless of the charging level.

The Middle Ground: Balancing Range and Battery Life

Ultimately, the decision to charge your EV to 80% or 90% depends on finding the right balance between driving range and battery lifespan. Maximizing battery longevity is undoubtedly important, but it shouldn't overshadow the convenience and functionality that a higher SoC offers, especially for longer journeys.

It is worth highlighting that even though charging to 90% can result in slightly faster battery degradation, the impact may not be significant enough to outweigh the benefits of the additional driving range. However, charging regularly to 100% is generally discouraged unless necessary since it can lead to accelerated wear on the battery.

Ultimately, understanding your specific EV model, battery chemistry, driving habits, and local climate can help guide your charging decisions. Additionally, it's recommended to consult your vehicle's manual or reach out to the manufacturer for detailed guidelines on charging practices tailored to your EV.

In conclusion, charging your EV to 80% or 90% is a decision influenced by multiple factors, including battery chemistry, charging habits, and temperature. Striving for a balance between battery longevity and driving range is key. By considering these factors and understanding your specific EV's needs, you can make an informed decision and optimize your charging practices accordingly, ensuring both a reliable driving experience and long-term battery performance.