Why is my battery draining so fast after updating to Windows 10

[WPCentral Question]

Have Lumia 925, prior to update my battery lasted a day with regular calls/WhatsApp/ Surfing, but after updating to Windows 10 its just 5 hrs with a call or 15 min and 10 min surfing internet.

Can anyone help us get a Fix ASAP, this is making the phone unusable...