Overcharging does not, in fact, harm the battery.
Apple has been under quite a bit of scrutiny in the past few days over the way the new iPad’s battery charges. Shortly after the new iPad’s launch, it was discovered that when the tablet is plugged in, it continues charging for as much as two hours after the battery indicator reaches 100%. While this might be frustrating, it’s not actually a major problem. Many devices read as fully charged before the battery actually reaches 100% in order to preserve the battery’s health. Since the new iPad’s battery is so much larger than the batteries in other devices, it stands to reason that the gap between when the device reports 100% charge and when it actually reaches 100% charge would be bigger.The problem came from a CNBC report that claimed to offer Apple’s response to the issue. Here’s the video again, in case you missed it:
As you can see, the reporter in the video attributes the claim that overcharging the battery can damage it to Apple. That, as you might imagine, struck a nerve with a lot of people, including Raymond Soneira, who originally discovered the discrepancy between when the battery reports 100% and when it actually reaches 100%.
Apple has responded to the controversy today. Apple Vice President Michael Tchao toldAllThingsD that the new iPad charges in exactly the same way as every other iOS device. It reports 100% battery charge when the battery is actually not quite fully charged. At that point it continues to charge until the battery actually reaches 100%. Once that happens it stops charging and allows the battery to drain, then starts charging again to bring the battery back up to 100%. According to Tchao, if you unplug your iPad at any point after the battery indicator reads 100%, you should expect to get the promised 10 hours of battery life. What’s more, that charge cycle is in place specifically to avoid damage to the battery. The system is designed to allow users to keep their iPads (and iPhones, and iPod Touches, etc.) plugged in as long as they like with no ill effects.