Much like old humans, old iPhones have a tough time holding their juice — and part of the reason why is how you charge them. “Charging my phone is a breeze,” you say. “What could possibly go wrong?” you say. As it turns out, some of our seemingly harmless habits are doing slow, silent, deadly damage to those precious lithium-ion batteries.
If your palms start sweating when your battery drops below 90%, you need to chill. Maintaining a full charge is not the most efficient way to keep your phone battery strong. In fact, experts suggest letting your phone coast through the day between 30 and 80 percent full. That’s where it’s most comfortable, and will run most efficiently. So stop juicing it overnight, and instead go for shorter and more frequent bursts throughout the day.
Lithium ion batteries become volatile when they drop down to low power, so you should avoid getting that pesky “low battery” warning too often. Every full discharge wears down your battery ever so slightly. That being said, Apple and other experts suggest you let it fully run out of juice every one to two months to “calibrate” the battery gauge.
Okay, this isn’t specifically a charging issue. But it’s still very important. You’ve probably noticed that your phone is annoyingly sluggish after its been sitting out in the sun. That’s because iPhone batteries really, really hate extreme temperatures, and have to work extra hard in high heat or cold. According to Apple, the “comfort zone” for iPhones (as well as iPads, iPods, and Apple Watches) is between 32 and 95 degrees. Bottom line: your phone is basically a needy little computer baby that needs to be bundled up and cooled off on the regular.
Your mophie backup battery case is a godsend when you’re out & about and need some extra juice to get home. But both your battery and the case itself emit heat during charging, which can do long term damage your device. To avoid overheating, try a portable power source that doesn’t attach to your phone.
While we’re on the subject, if your phone feels too hot when it’s plugged in, it’s possible your fancy schmancy case might be trapping in the heat that’s produced while charging. So do your phone a favor and take it off.
If you’re hanging onto your old phone as a backup for when you inevitably drop your new 6S in the toilet, make sure you stash it in a cool place, roughly half-charged. According to Apple, it you leave the battery completely depleted it will fall into what’s known as a “deep discharge state,” which apart from sounding like a nightmarish medical issue, will render it less capable of holding a charge in the future. Conversely, if you store it fully charged for an extended period, it may lose some capacity as well.
Your Apple-issued charger is designed to cut power when the battery hits 100%, but those cheapo unauthorized third-party USB cords are not, and may do some damage by excessively juicing the battery. Plus, ya know, they could kill you.