[header] How to keep low power mode on after the battery charges on an iphone [title] Charge your iphone. [step] Connect the usb/lightning cable that came with your device to your iphone and to the charger. [title] Monitor the battery level. 
[step] Keep an eye on the battery percentage, until it's charged between 75 and 80 percent. [title] Remove your iphone from the charger.