text: This phone case has to be turned on to work, and it shuts off automatically when it detects the current drop below a threshold. Unfortunately this threshold is set way too high. When your phone's internal battery reaches near 90%, it slows down charging to a trickle. The battery case decides to shut off at this point. The problem with this is that you cannot run your phone for a long time without regular intervention. The battery case has to be repeatedly turned on. So, if you were hoping to extend your phone's battery life without having to turn the battery on over and over, you're out of luck. If instead you just want to treat this battery like a spare where you push a button to top off your phone's internal battery, that will work fine. On the upside, the USB port does still work to pass-through data. All ports are still accessible on the phone (although the headphone jack is tricky depending on your headphone plug). Even the NFC reader still works just fine on the phone through the case. This is the only battery case available for this phone, so if you need it, you're stuck with its deficiencies anyway.