Guaranty it isn't Skype video, I selected it and it says I am not signed in. I also changed the email sync setting just now, couldn't find them before.
I usually listen to Groove on my bluetooth headset, but today I listened to Pandora for 7 hours or so, had 5% left after like 11 hours. Battery usage shows 54% to Pandora, Messaging & Skype 12%, MS Edge 11%, five more less than 2% and the rest <1%, that is for the last 24 hours.
In use shows 40%, background 60%.
Tomorrow I'll try Groove again an see if it is near Pandora, I expect high 40's because it isn't much better.
My issue is that with some other W10M builds and W8.1 it would have 35-45% remaining at 16 to 17 hours use with 7 of those just like today streaming for a good amount of time. Oh, FYI I am on WiFi almost 95% of the time, I do occasionally go on road tests and then it would be on cell data, but it is not usually any significant amount of time.
I don't want to use W8.1 but I still have issues with Cortana too, that was better in W8.1. I am pretty sure the issue is the OS, not my use or the device.