Apple's iPhone battery life is always a major concern for owners. But in its new iOS 13 operating system Apple plans to launch later this year, it'll come with a new feature for preserving that precious battery life.

The folks over at Apple-tracking site Cult of Mac have been taking iOS 13's beta for a spin and found a new feature baked into the operating system's Battery Health menu called "optimized battery charging."

Apple describes the feature, which you'll find hidden in the software, as a tool that "helps slow the rate of battery aging by reducing the time your iPhone spends fully charged. iPhone learns from your daily charging routine so it can wait to finish charging past 80% until you need to use it."

That's right. In order to extend your iPhone's battery life, Apple's tool will stop you from charging the smartphone's battery to 100 percent. Instead, you'll only be able to charge it to 80 percent most of the time, and based on Apple's analysis of your use, every now and then, it'll bump the charge to its full capacity.

At first blush, that might sound like a bad thing. After all, if you're losing 20 percent of your battery capacity, wouldn't that mean that your iPhone's battery life will suffer and not be as long as Apple itself promises in its iPhone specification listing?

Temporarily, that's possible. But did you know that when you charge your battery to 100 percent and allow it to drain down to zero, you're actually doing more harm than good? And did you know that over time, if you keep charging your battery to 100 percent, your total capacity will drop. Less battery capacity means less battery life.

So, Apple's new tool in iOS 13 aims at fixing that by only charging your battery to 80 percent to extend its total capacity life. Initially, a brand-new iPhone charged to 80 percent won't last as long as one charged to 100 percent, but over time, as capacity drops more quickly with the 100 percenters, your 80 percenter will win.

Think of it like a sprint and a marathon. In the world of battery life, the marathon wins.

It might sound counterintuitive, but Apple is on to something with its new battery-saving tool. And believe it or not, it might just make for a far more appealing experience over time.