Apple is shortchanging new iPad owners on battery power, an analyst said today.
“If you stop charging the iPad when the battery indicator says 100% youwon’t get the maximum running time,” said Ray Soneira, president ofDisplayMate Technologies, in an updatedpaper on the new tablet.
According to Soneira, when the iPad’s battery meter first shows 100%,the tablet is actually charged only to 90% capacity, shorting users bymore than an hour on the device.
That may jeopardize Apple’s claim that the iPad can keep going for over10 hours, said Soneira.
If the iPad remains connected to an outlet, the remaining 10% ofrunning time — about 1.2 hours — is eventually added as the charge isslowly trickled to the tablet. All the while, said Soneira, the metercontinues to read “100%.”
Although the iPad’s software — which monitors the charging process toinsure that the battery is not overcharged, and thus at risk of damage– is generally working as designed, Soneira said there is “somethingwrong with the battery charge mathematical model on the iPad” thatresults in the inaccurate charge status.
“It should not say 100% until it actually stops recharging and goesfrom the full recharging rate of about 10 watts to a trickle chargingrate of about 1 watt,” said Soneira. “Otherwise the user will not getthe maximum running time.”
Soneira’s tests showed that an iPad that was turned on while chargingreached 100% capacity 2 hours and 10 minutes after the indicatorprematurely read full. If the iPad was off or asleep, the additionaltime needed to completely charge the tablet ran just over an hour.
Soneira also noted that a videoreport by CNBC last week claimed Apple said users coulddamage the iPad’s battery if they continued to charge it after themeter showed 100%.
“Apple is saying… if you charge it more than [when the batteryindicator reads 100%], you could actually harm the longevity of thebattery,” said CNBC’s Jon Fortt in that report.
There is no such warning on the Apple website, where the company offers battery longevity and charging guidance.Advice like that would also run counter to the long-standing practiceof leaving portable devices unattended while charging.
Apple did not immediately reply to a request for comment on Soneira’sfindings or CNBC’s claim that the company has advised users not tocontinue charging the iPad.
The new iPad sports a lithium-polymer battery rated at 42.5-watt-hours,a 70% increase over the iPad 2’s 25-watt-hour battery.
A bigger battery is necessary,said Soneira, to drive the tablet’shigher-resolution display and its backlight.
Apple may be able to tweak the battery indicator software with a futureiOS update to make it moreaccurate. The company has made similar movesin the past, such as in July 2010 when it revised the iPhone 4’s signalstrength meter during the brouhaha that then-CEO Steve Jobs called”Antennagate.”
Gregg Keizer coversMicrosoft, security issues, Apple, Web browsers and general technologybreaking news for Computerworld. Follow Gregg on Twitter at @gkeizer , on Google+ or subscribe to Gregg’sRSS feed . Hisemail address is firstname.lastname@example.org .