Battery draining problem with my smartphone LG G2

Hi,
Two weeks before I purchased smartphone LG G2. It was amazing and worked very well since yesterday.
But yesterday night I noticed that the battery status was showing 90%. After I woke up in the morning, I checked that the battery is shown at 5%. I got surprised. Because in my mobile I didn't add any applications except local weather and no other application running. I don't even have Wi-Fi at my home. I don't understand what might be the problem here.
Could someone figure out what is the issue with my phone? Thanks in advance for any help.
