Sudden reduction in battery life

[HondaMan983]

Good evening

Over the past several days, I have noticed my iPhone 13 Pro Max losing battery power at an alarming rate even tho' my usage has not changed. Up to that point the battery would last for at least a day and a half, now it drops to 50% in a very few hours.

Any helpful ideas appreciated

Thanks in anticipation

 

[Rod]

I'm sure you don't need me to tell you there are only two possibilities here. Either something is using up your battery or your battery is dying.
The first alternative suggests something has changed, a new app, new settings etc. You can check the Battery Health and Charging in Settings > Battery which will tell you the condition of your battery and which apps are using what percentage of charge.
If your battery is in need of replacement the same page will suggest that too.