The battery my Phone suddenly started 2 lose power very quickly

[AC Question]

Have not changed anything i am aware of

 

[Tim1954]

Charge it fully. Leave it on for a few hours. Go to battery and you will see what's using the power. If it's an older phone, the battery may have come to the end of its useful life. In that case get it replaced, if it suddenly fails you will be greatly inconvenienced.