Even though most conference have extra power stations – it never hurts to travel with some backup. This Mophie Powerstation is a 4000mAh 2.1A External Battery Charger for iPad, iPhone, iPod touch, DROID, HTC and BlackBerry. If your charging connector has a USB connector chances are the Mophie can power it.
During the conference we were recharging about 1.5 times and at speeds that were impressively fast. To recharge the Mophie simply connect it to any micr-usb charging connector. Cost is about $79 via Amazon or the Mophie website.