Heat up and Stand by drain

iPhones perform many tasks in the background (syncing, backing up, analyzing photos, etc) so it’s normal to deplete battery even when not in active use. It’s also normal for it to get warm when charging. Unless you see the screen below, it is not overheating.

Both aspects are, however, exasperated by the age of your iPhone. If you bought it when it came out, its battery is six years old! It’s at the end of its useful life, or past it. As of right now, iPhone 6 is still supported by Apple. If you intend to keep it for a while longer, I suggest investing in a replacement battery.

Hi there SAwais,

It sounds as though you're experiencing shorter battery runtime as well as noticing your phone becoming warm when on a charger. You're in the right place to seek a solution and I'd be happy to assist.

Below is a resource that can help:

About the battery usage on your iPhone, iPad, and iPod touch

First, this resource can assist with checking the amount of battery used by each app to see if there could be an app using more than it should.

Next is a resource that provides additional information on the battery and performance in iPhone:

iPhone Battery and Performance

This resource provides great information on the battery inside your iPhone as well as details on how to check information such as Battery Health.

Finally, below is a resource that can provide information on acceptable operating temperatures for iPhone, iPad, and iPod touch:

Keeping iPhone, iPad, and iPod touch within acceptable operating temperatures

I hope this helps,

Cheers!