Softbank Mobile today announces a new external battery for iPhone 3G, letting iPhone 3G users in Japan to charge their iPhone anytime anywhere. The battery extender can also receive the One-Seg media broadcast, it will then transmit the video via WiFi signal to iPhone 3G. With one full battery charged it can receive and transmit video continuously for 3 hours. The company plan to start selling the add-on from mid-December this year.