We got these and the company even sponsored our Ingress tournament event. http://www.amazon.com/10000mAh-Portable-External-Smartphones-USB-charged/dp/B009USAJC

We got these and the company even sponsored our Ingress tournament event. http://www.amazon.com/10000mAh-Portable-External-Smartphones-USB-charged/dp/B009USAJCC http://www.amazon.com/10000mAh-Portable-External-Smartphones... $40, big battery capacity, nice design, quality, and durable.