You don’t need the latest and greatest smartphone to get all-day battery life. These days, most midrange or budget options can get you through a full day on a single charge. Instead of prioritizing day-to-day battery life on my iPhone, I’m focusing on its battery lifespan, how long the battery remains in good condition over the course of my phone’s life.

One way to improve your phone’s battery lifespan is by minimizing the time it spends charging when the battery is 100%. A fully charged battery can experience stress, which reduces its health in the long term and causes it to degrade faster.

If you have an iPhone, it may already be learning your charging routine thanks to Optimized Battery Charging. With this feature enabled, you can keep your device plugged in overnight, and it won’t charge to 100% until the next morning.

How to set a charge limit

If you want even more control over your iPhone battery, you can use a feature called Charge Limit. By setting a Charge Limit, you can prevent your device from reaching its maximum capacity, which can help reduce strain on the battery.

You can enable Charge Limit on iPhone 15 or newer models by going to Settings > Battery > Charging. There, you can choose a percentage at 5% increments between 80% and 100%. (Note that Optimized Battery Charging can only be toggled on at 100%.)

Should you ever charge your phone to 100%?

According to Apple, a Charge Limit can improve your phone’s battery lifespan and iOS might recommend it based on your use patterns. Even if you only limit your charge to 95%, the feature can have long-term benefits for your iPhone. 

However, you shouldn’t lose sleep if your phone is still plugged in when the battery is full. «There are so many different variables that affect battery age and longevity besides just filling it to 100%,» says Patrick Holland, CNET editor and phone reviewer. «Apple and other phone-makers use software to minimize those factors, and even give customers ways to take control of that if they like. But there’s a balance and people shouldn’t be afraid of topping off their phone completely.»

You might occasionally still see your iPhone charge to 100% when you’ve enabled Charge Limit. «If you have Charge Limit set to less than 100 percent, your iPhone will occasionally charge to 100 percent to maintain accurate battery state-of-charge estimates,» according to Apple.

For more iPhone battery tips, check out the iOS settings that can drain your iPhone battery, and learn whether permanent Low Power Mode can make your old iPhone battery last longer.