I think my Siri is using excess battery in iOS 10. I don't know if this was like this before but I looked at my battery usage and I Noticed Siri is a 10% - I seldom use Siri unless I'm in the car sending a text.
My 4 months old SE still have better run time than new iPhone 7. The 7 has 7 hours usage standby 1 day with 27% juice left while SE has 5 hours usage 32 hours standby and 50% left.