battery problem

[Zakhwan05]

So I have Lenovo a6600d40...running android 6.0...2300mah battery...the problem is...if I charge my phone while shutdown is during the shutdown is showed that I charged 18% but after booting up the phone the battery will become about 35 40% but it will drain real fast

 

[Mooncatt]

That phone was released two years ago. Depending on how long you've owned it and your usage habits, I suspect the battery is just at the end of its life and due for replacement.

It's also an extremely low spec phone in today's world. If it's having trouble keeping up with current app demands, basically running it at full power most of the time, that could be causing the fast draining too.