S9 plus battery life

[Bloomy1976]

My S9 plus battery life is pucker my only isuue is when it gets down to 10% it will drpp straight to 2% without battery count down usually happens if I've been say using WhatsApp just close Facebook soon as I close all the apps off it does it when it's that low anyone else come across this i dont know weather this is normal because of screen and power or battery cell knackered

 

[belodion]

Welcome.

It could be a bad battery.