Heavy battery drain in S9+

[Evan0202]

Please help with the battery drain in S9+. Its been running on Pie for the past 4 months, and things took a turn last week. I wiped the cache partition, recalibrate the battery and even did a full factory reset. My idle time drain is huge, 20-30% drop by the time I wake up. No change when used on airplane mode and moderate power saving. 

[BasselK]

You should check device care for the apps running in the background and the percentage of their battery consumption per day, try putting unused apps to sleep by default, you can also visit an authorized Samsung service centre to check your battery health for free.

[MittuVichu]

Usually battery optimisation will automatically start working when the device is idle. When you lock your phone and the screen turns off, android will automatically put certain apps and features into sleep mode. In this case we can see a uniform decrease in battery graph almost 50% which is not common in a healthy device, especially when the device is idle.

[Evan0202]

The phone was charged to 95% before I went to sleep. All apps closed. I took it to the service centre, but they assured the battery is physically in perfect condition

[MittuVichu]

If this is the battery graph when the device is completely idle, then there is some issue with either the battery or the motherboard.
Take the phone to service centre. If they still say phone is okay show them the battery graph. In the graph there are no apps another than some system options which used battery. Its very rare that these 3 options will use 50% of battery especially when the most power consuming part, the display itself was working just for 14 minutes.
Also the batterys idle time will increase if you use the phone in flight mode as the network is completely off. In this case you say there is no difference at all between flight mode on and off.
See the attached screenshot of my battery usage.

[Evan0202]

yea, I know this ain't normal. I used to get 18+ hours with the smart watch connected and 5+ SOT.

[BasselK]

So better to go back to Samsung service centre.

[happyazar]

no use of discussing all these. there is no response from samsung regarding this battery drain issue. i have done all the check points.no use. when i removed my S9+ from charger,it shows only 10hrs. before it was 18+hrs. really fedup