My battery keeps dying while it is backing up to the cloud, even though it is plugged into a power source. Help!

Greetings Anaberta,

Thanks for visiting the Apple Support Communities! I understand you're concerned with the battery in your iPhone, as you mentioned your iPhone is turning off while connected with a charger.

I suggest checking the battery health of your iPhone. The following support article provides helpful steps for checking the battery health, maximizing the performance of the battery of your iPhone, and preventing unexpected shutdowns: iPhone Battery and Performance - Apple Support

If the behavior persists, the following guide will help you to prepare and arrange service for your iPhone: Get your iPhone, iPad, or iPod touch ready for service - Apple Support

Kind regards.