You’ve been lied to, but it’s for your own good. Most devices are designed to never fully charge or discharge their battery because the extremes are when they're most unstable. Instead, devices use roughly the middle 80 percent of a battery's capability. So the next time your phone says it's 100 percent charged, tell it you know the truth.
The reasons are too numerous to mention, but safety far outweighs the rest. Batteries with poorly made separators can suddenly fail — and catch fire. And chargers without adequate protections can send too much energy to your phone, causing an explosion. Don’t believe us? The next time you hear about someone’s phone exploding, read beyond the headline: a cheap charger is almost always at fault.
Apple and Google are smart companies, and they know that if smartphone applications run all the time, battery life suffers. Both companies’ mobile operating systems prevent apps from sitting open unused. Even though Apple iOS, for example, shows a long list of recently used apps when you double-click the home button, they’re not running. A program closes automatically within minutes of your moving on to another task.