Finally a device that allows me to overcome the battery charging problems of my S3. I just got it and I've tested: the battery is charging fast enough (at least faster than the live cable to the smartphone !!) Delivered without notice, but is it useful? one branch, the light is purple when that load, blue when it's ready. As noted by other buyers: no overheating of the battery. At this price it should not hesitate! I tested on the original battery, there I am trying it with a long replacement battery (model slightly thicker than the original) and it works too.