By doubling the number of LEDs in the new iPad, Apple cut somewhat into battery life--particularly when used at full brightness--something you won't find on Apple's tech spec page.
Though the new iPad's battery is 1.7 times larger than the iPad 2's, all of those extra LEDs still take a toll on battery life at full brightness--as Raymond Soneira, president of DisplayMate Technologies, told.
"The [power consumption of the] LEDs is 2.5X compared to the iPad 2, and the battery is 1.7X [larger]...so what happens is that if you run your new iPad at full brightness, the battery run time is less because you only put in 70 percent more battery but you're using 150 percent more power," Soneira said. (See chart below.)
While full brightness battery life went south, lower settings are pretty much the same. "So, at full brightness the new iPad lasts 20 percent less than the iPad 2. But in the middle range, the new iPad runs essentially at the same running time as the iPad 2. And, in fact, that's the way Apple delivers it and that's probably the typical setting," he said.
More specifically, that's the brightness slider set at 36 percent, Soneira said today in a follow-up interview. He described this as more or less as the default setting on the iPad.
Still, there are plenty of people--just check out the Apple Support Community forums--who insist on using the iPad at full brightness.
It all comes down to LEDs. The number of backlight LEDs has roughly doubled from 36 to an estimated 72 to 82, according to Soneira. "Since the display normally consumes about 50 to 60 percent of the total tablet power, the new iPad needs at least a 50 percent larger battery," he said in report, echoing what he told CNET above.
Soniera's analysis meshes more less with a test CNET's Eric Franklin. He evaluated the battery life by continually running a movie file on the iPad until its battery dies. The new iPad drained in 12.8 hours, faster than the iPad 2's drainage rate of 14.2 hours. But Franklin points out that 12.8 hours of battery life "is still the second-highest result we've seen on a tablet using a single battery."