There have been a number of issues reported with the new Apple iPad. According to Apple, though, the concerns being reported about the iPad battery are not issues at all—just the device doing what it was designed to do.
There are two issues being reported by used when it comes to the battery. One is that the iPad battery is not fully charged at the point that the display indicates it has reached 100 percent. The other is that the device takes significantly longer to fully charge than its predecessor.
Dr. Raymond Soneira of Displaymate Technologies first raised concerns over the accuracy of the new iPad reporting that it’s fully charged. He found that the iPa seems to take another hour or so to truly be fully charged even after it reads 100 percent.
Soneira is correct. However, the behavior is apparently not unique to the new iPad, and is not an issue at all.
To stay fully charged while plugged in without overcharging, all iOS devices report fully charged before they’re quite at 100 percent. When the device really does reach 100 percent, the charging circuitry stops and the battery begins to discharge. But, when it drops a few percentage points it charges again and the process continues so the device is always at or near a full charge without damaging the battery.
Apple VP Michael Tchao told AllThingsD, “That circuitry is designed so you can keep your device plugged in as long as you would like. It’s a great feature that’s always been in iOS.”
Tchao stressed that iPad owners will experience the 10-hour battery life Apple claims from the new iPad even if they unplug it and start to use it when it says 100 percent, but hasn’t actually reached its full capacity.
As for the battery taking longer to charge, that is also normal behavior. The new iPad takes longer to charge than the iPad 2 for the same reason that my Chrysler minivan takes longer to fill up with gas than my Toyota Prius–it has a larger tank, or in this case charging capacity.
The new iPad has a 42.5 watt battery compared to the 25 watt battery in the iPad 2. All else being equal, a battery that is 70 percent larger will take longer to charge.