After an restore and trying everything as optimizing battery and other ******** things, is this a faulty battery or an issue related to motherboard and the unit is faulty?! Any suggestions?
Which iPhone do you have?
It's an iPhone 5S with 520 cycles and 95,62% of capacity!
The battery might need replacing. I'm assuming this is the original battery in the iPhone? How long have you owned the iPhone for?
Additional information on lithium ion batteries:
https://www.apple.com/batteries/why-lithium-ion/
Well, bought from second hand, but assured that was never replaced as battery, so I'm thinking it's the original battery!
95% capacity? Holy cow, my 6s is at 86% and lasts longer. You need to look in the settings because something is working in the background. Also try "battery life" from the app store, it s a simple app that shows the life of the battery.