What is happening is this. Your iPhone requires less power to charge while it is off, than it does to charge and run the phone while it is on. The charger you are using is supplying enough amperage to charge the battery while the phone is off. Once the phone turns on, the current draw is too much for the charger to keep up with, so the phone starts draining the battery again. Apple chargers will not have this problem. Switch to a genuine Apple branded charger and see if you continue to have this problem, it is unlikely you will.
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Your iPhone requires less power to charge while it is off, than it does to charge and run the phone while it is on. The charger you are using is supplying enough amperage to charge the battery while the phone is off. Once the phone turns on, the current draw is too much for the charger to keep up with, so the phone starts draining the battery again. Apple chargers will not have this problem. Switch to a genuine Apple branded charger and see if you continue to have this problem, it is unlikely you will.
What is happening is this. Your iPhone requires less power to charge while it is off, than it does to charge and run the phone while it is on. The charger you are using is supplying enough amperage to charge the battery while the phone is off. Once the phone turns on, the current draw is too much for the charger to keep up with, so the phone starts draining the battery again. Apple chargers will not have this problem. Switch to a genuine Apple branded charger and see if you continue to have this problem, it is unlikely you will.