Winten 5200 mAh WT-P52S-BK mobile external battery pack, with 1x high (5V / 800mA) USB Output for iPhone, iPod Touch / Nano; Smartphone, Black (Wireless Phone Accessory)
We have the battery pack for several months in use. Since the first was broken, we were sent a new problem (Thanks for the good service Winten GmbH). It manages our HTC 7 charge on twice. However, the time the battery pack to recharge is quite long.