Safety even when charging your phones

You may already have heard the warnings: Don’t overcharge your mobile phone. Make sure you unplug it from the charger after it reaches 100%. Don’t leave it charging overnight. Or else.

The direness implicit in those imperatives may be overblown, but they’re not paranoid conspiracy dictums — you still shouldn’t overcharge your phone. Here’s why.

Mobile phones contain a rechargeable lithium-ion (or li-ion) battery. Li-ion batteries charge faster than traditional rechargeable batteries. That’s why you can plug your iPhone or Android phone into a charger, and revving it up to at least an 80% charge happens fairly quickly. But as we all know, our smartphone battery charges don’t last long. We’re often lucky to get through the day without our phones losing all their juicePart of that dilemma is because the batteries on our phones are relatively small and can hold only so much capacity. But the other part is due to the way we use our phones. Constantly checking email, texting people, listening to music, watching videos, using apps, playing games. All those activities eat up a single charge, causing our phone batteries to run out of gas, often sooner than expected.

For that reason, many people (myself included) probably charge their phones overnight. You then wake up to a 100% freshly charged phone in the morning when you have to trot off to work or otherwise start your day. In most cases, your phone probably needs only an hour or two to hit 100%. Leaving it plugged in longer is pointless. So what happens if you act as I assume most do, and leave your phone plugged in overnight?

First, the good news. You can’t overcharge your phone’s battery, so don’t worry about that. Your phone stops drawing current from the charger once it reaches 100%, according to Cadex Electronics marketing communications manager John Bradshaw. Cadex manufactures battery charging equipment. “Go ahead and charge to 100%,” Bradshaw says. “No need to worry about overcharging as modern devices will terminate the charge correctly at the appropriate voltage.”