New iPhone 16 will not hold a charge
iPhone 16 battery is dying and needing to be charged multiple times a day. My 12 was much better. What will this be like when it’s old if new it is horrible.
iPhone 12, iOS 17
Charge overnight, all night, every night. It should be fully charged in the morning, and should last to the next nightly charge.
Note, however, that the first couple of days after an update or a new phone it has a lot of “housekeeping” to do that may use extra energy. Charging overnight speeds this process up.