Plug in your iPhone or iPad and charge it up, and you’ll notice that while the first 80% or so will go by pretty fast, they actually kind of suck at charging up that last 20%, taking a lot more time to do so than it feels like they should.
There’s a reason for this. Charging batteries up to “full” is a complicated process. There’s no real way to tell if a battery is completely “full” so all you can do is measure the voltage, which (and this is a vast simplification) tells you how much resistance is being met when you try to put more electricity into the battery.
That’s why it takes so long for an iPhone to charge that last 20%. It charges full blast until it measures a certain voltage, then goes into what’s called “trickle mode” to slowly allow small sips of electricity into the battery until it thinks, based upon some software calculations, that the battery is more or less full. But a new algotihm could make the time it takes to charge your iPhone or iPad go by a lot faster.
If you’re an iPhone user who plays Angry Birds and watches YouTube videos all day long, you probably think your handset’s battery life is terrible. In reality, the iPhone often provides you with a lot more energy than many rival smartphones, and as for the iPad, well, no other tablet beats it when it comes to staying awake.
But there are some things you can do to make your battery life even better. In addition to obvious fixes — like turning down your brightness when you don’t need it to melt your retinas, or killing apps like Skype that constantly run in the background — identifying buggy apps that might be using battery unnecessarily could make a huge difference. And Carat for iOS helps you do that.