Battery Iphone Xr

Hey there, azizah64!

Thanks so much for using Apple Support Communities.

Your iPhone XR has a lithium-ion battery which is designed to let you charge it whenever you want. You don't have to wait until the battery dies or drops close to 0% before you can plug it in. Charge whenever it is convenient for you and you'll be good to go. You can learn more about lithium-ion batteries right here: Batteries -- Why Lithium-ion?

Another good resource we want to share is: iPhone Battery and Performance

This article will help you get the best possible battery life from your iPhone and includes tips and tricks to make that battery work at its absolute best for you.

We hope that this information is helpful.

​Have a great day!

azizah64,

Auto-brightness is actually a great way to help your device manage your battery life and actually extend overall battery life. You can learn more about that here: Maximizing Battery Life and Lifespan

We hope this helps!