New iPad's charging math wrong?!

Research firm DisplayMate says the math behind the latest iPad's charging indicator is wrong, providing users with misinformation about when their gadget is fully juiced. iPad's behavior here can be attributed to the calculations that go into determining how far along the recharging process is based on battery health and other factors.

Apple did not immediately respond to a request for comment.

DisplayMate's original report -- based on its own testing -- found that the full power draw while charging Apple's latest iPad continued for about an hour after the on-screen display said the battery was at 100 percent. That meant those who unplugged the device at that point were potentially getting less of a charge than if they let the device keep charging, the firm said.

After additional testing, Soneira said it takes an additional 2 hours and 10 minutes after the battery reports 100 percent for the recharging cycle to "fully" terminate.

Apple's latest iPad has a considerably more powerful battery than its predecessors, jumping from a 25-watt-hour lithium-ion battery to a 42.5-watt-hour battery. That change came in order to power a display with four times the number of pixels as previous generations, a dual-core processor with a quad-core graphics chip, and 4G LTE wireless networking on some models. All told, that's led to battery life that's about the same as the iPad 2, while adding extra weight and thickness to the unit itself.

Apple has tweaked the mathematic formulas behind its on-screen indicators before, primarily the one that told users what kind of reception they had on the iPhone 4. Following its 2010 press conference centering on the performance of the antenna on that device, Apple said it was adopting a new formula for calculating how many bars were displayed on screen based on signal strength. That change came in the form of an iOS software update, which also made the first three bars of that signal range taller.