According to media reports, testing of Apple’s new iPad3 battery charger display revealed that the battery is actually only 90% charged when the display says that it is fully charged at 100%, which was said to result in more than an hour less running time off of battery power. Controversy increased when it was reported that Apple answered the questions surrounding its battery charge function by claiming further charging the iPad3, when the battery indicator reads full charge, could result in harming the longevity of the battery.
Critics responded that damaging the longevity of the battery is then exactly what the new iPad’s internal battery charging hardware and software are doing since it is their responsibility to properly control and manage the battery recharging process. The assumption was that Apple had configured the new iPad to damage the longevity of its own battery if it isn’t manually disconnected from the ac charger when the 100% indicator appears. This would that anyone recharging their iPad unattended, especially overnight, would be doing this.
Apple responded to the reports by noting that the new iPad, like all devices powered by iOS, reports a fully-charged battery before it actually reaches 100%. The company says that the iPad, iPhone and iPod Touch all display "100%" on their battery indicators before they are completely charged. The battery continues to charge until it is, in fact, at full, when it goes into a cycle of slight discharge-recharge-slight discharge until the device is unplugged.
The company denied that it has told users not to let the iPad charge after the meter reads 100%, stating that a recommendation like that would run counter to the long-standing practice of leaving portable devices unattended while charging.