Have you ever heard about the 80% rule? If you own an electric vehicle or planning to buy one, you need to be aware of this paticular rule. A commonly held perception about charging EVs is that it's not good to use an EV battery at its extreme limits. But why is the 80% rule? This article will explain how this rule affects EV battries.

Why you should follow the 80% charging rule for most of the time?

• Charging speeds slow down after 80%

Charging rates slow down dramatically past the 80% mark. EVs don't charge at a constant rate from 0-100%. The charging rate will change based on the battery's state of charge. The fuller the battery is, the slower it absorbs energy. Knowing this rule can save you a lot of time for daily charging. And if you are on a long way journey, it's smarter to shop at 80% when you charge.

• Long-term battery capacity is improved at 80%

The EV battery packs typically employ lithium-ion chemistry. Charging to 100% can lead to reduce capacity of the battery. It can also cause degradation, reducing the effectiveness of the electrochemical energy exchange. If you are always concerned about fully charging, you don't have too. A lot car companies make this easy to do with an system that allows you to set your preferred charge level.

Can you charge to 100%?

You can still charge to 100% if you are going for a long drive. The 80% rules are mostly for the common daily driving. The other reason for charging to 80% is when you're at a DC fast-charger. If you don’t need that last 20%, don't waste your time (and potentially delay others waiting for that charger) by staying there.