In my experience an ultra always lasts a day, always… unless you do over 12+ hours of gps use like on a day hike you are tracking or a full length Ironman. I’m sure using it as a cellphone for a lengthy time would also kill it. But “normal” watch use? A busy day kills around 50% at most for me.If this is true it will be getting returned. I only use the ultra cause of the battery life...I dont need 42 hours, but I need it to always last one day, which the regular models do not.