My more than 2 years old 735 has a strange behavior: After my runs the battery level increases again! For example yesterday I started my 15km run with 58%. After returning 1.5hrs later 23% were left. When I looked at the watch 2hrs later it was back to 40%! Well, it was cold outside but I had this "recharge" during summer, too! Not such a big difference but it was there. A rather big drain (I use HRM Run) and then recharge itself. Even more battery drain while walking (with another data field and oHR). But also with recharge after the walk. I can't remember this behavior the last winters. Such a drain and then such a recharge itself. Is the battery already week or is there another cause?
