Couple of days back, we reported that the new iPad continues to draw power even after the iOS battery indicator reports 100% charge.
DisplayMate now reports that after testing the new iPad for some more time, they’ve observed that it draws power for more than 2 hours after the iOS battery indicator reports 100% charge.
Dr. Raymond Soneira of DisplayMate Technologies told PCMag:
“At 2:00 hours after reporting 100% charge, the new iPad hardware started to reduce the charging power. At 2:10 the recharging cycle fully terminated with a sharp decrease in power. The new iPad battery is truly fully recharged 2 hours and 10 minutes after prematurely reporting on screen that it was fully charged,”
However, Soneira points out that the new iPad is not the only tablet to display such a discrepancy. He believes that there is a bug in the way Apple is computing the battery charge:
“Other tablets and smartphones also lie about their charging status. The charge indicator on all mobile devices is based on a mathematical model of the charge rates, discharge rates, and recent discharge history of the battery. It uses this information to estimate how much running time is left. … So there is something wrong with the battery charge mathematical model on the iPad”
Soneira points out that since the new iPad uses the same power adapter and internal charging circuitry of iPad 2, it is taking longer to charge as the new iPad’s Retina Display takes 7 watts of power compared to the iPad 2′s 2.7-2.8 watts. Soneira reports that in their tests he found that the new iPad takes about seven hours to charge compared to iPad 2, which took 4 hours. And if you add the 2 hours where it continues to draw power, the new iPad takes 9 hours to fully charge.
It is not clear whether iPad 2 continues to draw power after reporting 100% charge, if it doesn’t then it means that iPad 3′s battery, which comes with a bigger battery that has 70% more capacity, takes more than twice the time to charge compared to iPad 2. Though we expected the third generation iPad to take longer to charge due to the extra capacity, we didn’t expect it to take so much time.
While it is not such a big deal, it is nice to know how much time it takes to charge the new iPad, so you don’t forget to leave it overnight for charging.