With Windows 8.1, I was able to put the Surface 3 to sleep at night and wake it up in the morning with almost the same battery level. Now with Windows 10, the Surface 3 is experiencing significant battery drain overnight. I put it to sleep last night with 54.5% battery charge. Now this morning, I just woke the S3 up and the battery charge is 33.4%. Are you guys experiencing something similar running Windows 10? I hope there is a fix soon.