Rigorous test results released this morning from DisplayMate Labs, run by Dr. Ray Soneira, conclude what some in the Apple support community are already discovering about their new iPads: the battery life indicator is displaying 100% charged when in fact it is really at about 90%.  

The discovery comes from the labs of Soneira and his DisplayMate company, an independent display technology test lab, which adds scientific rigor and test standards to all things display. In a press release on Sunday, Soneira concludes, "The battery is only 90% charged when it says 100%" on Apple's new iPad.  But the pain doesn't stop there. Soneira discovered that to recharge the device takes a whopping 5.5 hours when the new iPad is fully discharged. So what's going on? 

What's the Matter With the Battery Indicator?

According to Soneira, the battery charge indicator uses a mathematical model that includes the charging rates, discharge rates and the recent discharge history of the battery. These are estimates of how much runtime is left, and accuracy is no trivial matter, as "...most batteries degrade slowly as they discharge and then tend to surprise with a precipitous decline near the end," he writes. He also notes that because batteries are based on "complex chemistry," there is no way to measure the charge level in hardware. 

So there is something wrong with the battery charge mathematical model on the iPad. It should not say 100% until it actually stops recharging and goes from the full recharging rate of about 10 watts to a trickle charging rate of about 1 watt. Otherwise the user will not get the maximum running time that the iPad is capable of delivering," Soneira said.  

Effects as the Community Takes Note

You don't have to look far for evidence consistent with these findings, as it's popping up among the new iPad early adopters. On the Apple Support Community web site articles under the headline, "New iPad battery drain," first-time charging experiences are being written up with results of 10% battery loss from overnight in standby mode. "That's 10% for standby without loaded apps as the thing was down to 0% (shutdown) before I started charging," writes Meneer Tuur from the Netherlands on March 26. "I don't see that happening on my iPad 1 (same apps running) and phone. Is this normal?"

Soneira's explanation is that the new iPad was actually at 90% while the meter showed 100% on the display. 

New iPad May be Damaging Its Own Battery

Life would be simple if it were just a matter of correcting the on-screen battery indicator, but Apple has put forth "a rather shocking reverse perspective," according to Soneira, that the onscreen battery indicator is instead the correct one. John Fortt of CNBC reports in a video today that, "Apple is saying... if you charge it more than [when the battery indicator reads 100%], you could actually harm the longevity of the battery." 

In short, the new iPad running time, based on a fully charged battery, is 11.6 hours, but to get there you need to charge the battery beyond its 100% battery indicator (with an actual charge of 90%) that also delivers the marketed runtime of 10 hours. The downside to delivering the 1.6 hour boost is potential long-term damage to the battery.