Keep charged with this DigiPower RF-A52 portable charger that is compatible with most USB-powered devices. The 5200 mAh capacity offers extended use of your device, and it features a USB port and a 4-LED charge indicator for convenience.
I'm very cautious when buying power banks for my phone as advertised capacity is often not completely truthful. Here is a battery that actually charges as much as you would expect. I have an iPhone 6S Plus and I get about 1.5x charge out of this guy. The only drawback is it takes literally hours to charge this battery. Discharge (charging from the battery) rate is normal.