Why Holding Off Full Charges on Your iPhone 15 May Not Be Ideal

Key Takeaways

• Apple introduced a new feature in the iPhone 15 that allows users to limit charging past 80% to improve battery health.
• Enabling the 80% limit may result in a shorter daily battery life, as you are immediately losing 20% of your phone’s battery capacity.
• For most people, it is more cost-effective to use their iPhones normally and replace the battery when capacity drops, rather than immediately reducing capacity and potentially having to charge more often.

Apple introduced a new charging optimization feature with the iPhone 15 that allows you to artificially restrict how much of your battery the charging process uses, capping charging at 80% capacity. Here’s what it is, how to enable it, and a strong argument against doing so.

What Is the New iPhone 80% Charging Optimization?

Many smartphones allow you to limit overnight charging to around 80-90%, and then charge the last bit of capacity just before you take the phone off the power connection. It’s supposed to improve the lifespan of the internal battery, since keeping the phone at 100% on the charger for several hours straight can be worse for battery health.

Apple is now taking it further on the iPhone 15 series, with a new option to prevent all charging past 80%, though most people probably shouldn’t use it.

The iPhone 15 series includes a new Charging Optimization option that won’t charge your battery past 80% under any circumstances, alongside the existing “Optimized Battery Charging” feature that has been available since the iOS 13 update in 2019.

Apple explains in a support document , “When you choose 80% Limit, your iPhone will charge up to about 80 percent and then stop charging. If the battery charge level gets down to 75 percent, charging will resume until your battery charge level reaches about 80 percent again. With 80% Limit enabled, your iPhone will occasionally charge to 100 percent to maintain accurate battery state-of-charge estimates.”

How to Limit Charging on the iPhone 15

If you want to never change your iPhone past 80% capacity, it only takes a few seconds to flip the switch. Open the Settings app (ask Siri “open Settings” if you can’t find it), then navigate to Battery > Battery Health & Charging > Charging Optimization. Then, just select 80% limit.

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Your iPhone will now avoid charging past 80% capacity, except when occasional battery calibration measurements are required. If you want to go back to the default charging, go to the same menu and select “Optimized Battery Charging” instead of “80% Limit.”

You can also just select “None” for the iPhone to charge to 100% whenever possible, which might be the best option if you notice the phone isn’t fully charged in the morning or you rarely do overnight charging.

Should You Limit Charging to 80%?

Does it make sense to use the new charging limit feature? For most people, probably not. It’s supposed to reduce wear on the phone’s internal battery, since charging the last 10-20% of a battery cell causes more heat and strain on the battery cells. However, with the existing optimized battery charging that has been around for a few years, most people only lose 5-10% of the reported battery capacity each year.

With the charging limit option enabled, you’re immediately losing 20% of your phone’s battery capacity, which might even mean your phone doesn’t last a full day of usage (depending on what you’re doing with it). If you have to charge more often throughout the day, that’s still putting wear on the battery cell — likely not as much damage as charging all the way up to 100%, but it’s still something.

It’s also worth noting that a degraded battery isn’t a death sentence for an iPhone. Battery replacements for the iPhone 15 and other recent models cost $99 at any Apple Store location, and third-party repair centers like uBreakiFix/Asurion and Best Buy Geek Squad will likely offer battery replacements for the new models sometime soon.

For most people, it makes more sense to use their iPhones normally and replace the battery when the capacity drops too low (usually around 2-3 years), instead of immediately reducing the battery to that level and potentially having to charge more often. To put that in perspective, if you find yourself needing to replace your battery every 24 months, and it costs you $99, that’s essentially a $4.13 per month battery “tax” you’re paying to charge your phone to 100%. So, if you’re on the fence about using the feature or not, you may want to frame it in terms of “Would I pay four bucks a month to get more battery life every day and charge my phone less?” And if you make it to 36 months before you need a replacement, the per-month “tax” drops to $2.75.

When you look at it that way, suddenly artificially shaving 20% off your battery’s capacity seems less compelling. It’s great that the option now exists for niche cases, but we’d recommend you don’t sweat too much over battery health — it’s going to degrade over time no matter what settings you use so there’s no sense optimizing your battery to the point that you enjoy using your phone less.

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