Got the watch on Tuesday. Spent a few days learning about the settings. Full charge on Friday night, up to 100%. Short run on Saturday morning, 10% of the battery. Then, normal day with no other events. Wore the watch overnight, woke up to 53% battery.
I have Pulse OX off -- all the way off, sleep / daily tracking. I've turned off the seconds display. I'm not sure if there is anything else for me to mess with.
I had gone from the FR 230, to the FR645, and a brief stint with the Coros Apex (amazing battery, bad GPS / HR / Interface). I was really excited to get this watch as I met all of my needs. But I'm not keen on charging my watch EVERY day.