I have the same problem except the charging (i dont know how to check it, now i have a Aukey 2.5A charger and it runs perfectly).
My problem is this:
Windows 10 battery duration aprox. 3h- Browsing in Edge30min, watching videos in youtube 1080p 1h30min, Office 20min
Android – only a few little time each 30min aprox 10% even playing Modern Combat 5 – 30min x 10×10% – 300min – aprox 5h
I think is a drivers problem in Windows 10 but i can“t confirm, this afternoon im going to check the duration in Android mode. If the tablet runs 5h we can discard a hardware problem and it will be a software problem in Windows 10.
Regards
Daniel