3DS is a power-hungry device, a fact that Nintendo isn't hiding in the latest issue of Iwata Asks. Nintendo's Ryuji Umezu noted that the 3D display mode not only requires the device to render each image twice, but requires brighter brightness than a flat image. "In order to make it look just as bright as usual, you have to increase the brightness of the backlight, which increases the power used by even more," Umezu pointed out.
Thankfully, there are still some steps users can take to increase the longevity of the 3DS battery, such as turning off the wireless functionality (when it's not needed). Perhaps the most important of the power-saving options, though, is the system's "power save mode." Employing a technology called "active backlight," this feature "precisely controls the brightness of the backlight according to the brightness of the screen being displayed," Umezu explained. "When the screen as a whole is dark, the backlight itself gets darker, which saves power."
The energy savings offered by the power save mode should make it a requisite for every 3DS player. "With the backlight set to the brightest level and the power save mode turned off, battery duration was about three hours," Umezu said. "But if you use the power save mode under the same conditions, it gets about 10–20 percent longer." That's almost an extra half hour you could spend grooming your Nintendog ... or cat!