Looking to get a secondary charger and possibly a car charger and not looking to pay OEM retail. The print on included OEM charger reads: Output 5-15V & 2-1.2A (2-1.2A) Then, below that in another language it separated this to 5V @ 2A or 15V @ 1.2A My first question is what does this specific inverter actually output? If both, how/when does it know which one to choose? and Which one of these juice specs is ideal for prolonging battery life and charge cycles? I would assume the lower amperage, but 5V is basically universal as far as mobile device charging goes..