I am using a smart phone for GPS and it needs to be plugged to operate with the app and screen at full brightness. I had problems keeping the GPS operating, so figured to use an app to measure charging currents. Using a "belkin" car charger 2,1Amp and found the current fluctuating and reducing all the time reaching 30mA, 10mA and 0mA in 3-5minutes, letting the battery empty. In order to avoid possible problems on the car electrical system, I repeated my experiments at home, on a 12V switching transformer and found similar results. I used the app "Ampere" and "Battery monitor" on a Samsung S6. Anybody have ever tested your chargers with these apps? What is your experience with these chargers?