Try a different USB cable (for iPhones, try factory Apple USB cable)
Keep in mind that there are quite a few variables that can affect how long it takes for the GO PUCK to charge your phone or mobile device. Things like: the model of your phone/mobile device (some smartphones have very large batteries), brightness of your screen, being connected to WiFi, Bluetooth, 3G/4G, any open applications in the background, and having your location turned on (GPS), just to name a few. These can all consume power while your GO PUCK is trying to charge your device. This will reduce the time it takes to fully charge your device and the number of full charges your device will get from the GO PUCK.
If you feel like your GO PUCK is not charging your device as fast as it should, and is less than 1 yr. old, follow the link to our online warranty form here