Firstly, it's a brand new battery. I read on another forum that there could be a WM6.1 bug where when hard reset with a partially charged battery WM6.1 screws up and doesn't charge the battery fully as it mis-registers the charge level. So I drained it to critical, hard reset and then charged to full with the device off.
Once it was charged I didn't install anything on it and then managed to get 4 days out of the battery with the phone on during the day, and Exchange ActiveSync running. All was fine. I then recharged it, and set about reinstalling stuff, and now it's started doing it again. I turn of the radio when I go to bed, and leave any apps running, just live I've done with WM5 and WM6, and then in the morning, along with my alarm I get a critical battery notification.
I've tried monitoring the processes running and what CPU they're using and the pull on the battery, but nothing comes up abnormal, apart from once when I found repllog.exe was going on a rampage and stopping the device from sleeping. But the thing that really confuses me is that I can use the phone all day and the battery drain is as I would expect for the usage, but it only plummets overnight when the phone is off.
Anoyone got any ideas, as I'm considering sending it back to T-Mo and getting them to put WM6.0 back on it. I just want the thing to last 2 days like it used to, which isn't exactly spectacular, my partner only charges his Nokia once a fortnight.