It may pain you to add girth to the iPhone 5's slender frame, but when a little more junk in your iPhone's trunk means double the battery life, it's hard to say no. The new Mophie Juice Pack Helium case promises to do just that and be about 13% lighter than the iPhone 4's Air version.

Mophie claims the device, which is equipped with 1500 mAh of battery power, can offer up to 6 more hours of 3G talk time, six more hours of cellular browsing, seven more hours of Wi-Fi browsing, 30 hours of audio playback, or seven more hours of video playback.

The cases will retail for $80 (approx £50) and are supposed to ship in time for Valentine's Day (In the US), according to Mophie. Because nothing says "I love you and now you can never lie to me about your phone being dead again" like a battery-extending, emotionally smothering iPhone case. [TechCrunch]