Thank you for your invitation. Personally, I think there are two possible reasons
1, mobile phone battery problems
Insist on whether there is a lot of heat when the phone is charging, the power is off too fast, and the phone cannot be turned on. These may be the original fault of the mobile phone battery, or it may be caused by incorrect charging at ordinary times, you can bring the relevant certificate to APPLE's official repair store for repair, the cost is generally determined by the reason.
2, mobile phone charging mechanism
iPhone XR is paired with the iPhone's current largest battery capacity mobile phone battery, and coupled with the performance optimization of the A12 processor, lower power consumption, more durable. And mobile phone charging is generally high current fast charging before 90%, the natural speed will be faster to ensure the basic power, and 90% to 100% of the power in order to protect the battery is weak current trickle charging, because the battery voltage is too high, the battery will have a loss, so there will be a long charging time.
I hope my answer will be helpful to you.