Most of s9 and note 9 users are facing battery drain after 30 percent. Don't worry anymore its a software based error in battery measurement. Dial *#0228# and then tap quick start and then yes. After this simply let the phone shut down to zero percent and then charge it to 100 percent. Use it as usual and then again let it shut down to zero percent and again let it full charge. Repeat it 2 to 3 times after that issue will be solved. I have tried it , its really useful.
