I don't like the way Garmin just shut down threads they find uncomfortable.. this battery problem goes on and on and on... and their answer is to say send us your watch which one of our upgrades may have broken and we'll send you back a reconditioned one... oh, and we'll charge you £95 for it including postage. Anyway, for those suffering from this battery issue....
After countless hard resets my battery has settled into a weird yo-yo pattern. Today I charged it fully after it had behaved itself for four days, dropping from 83% to 39% slowly and dealing with two short runs as well. Within 10 minutes of reaching 100% today it fell to that same 39% within 15 minutes. So I charged it to 100% again and it fell to 55%. I then went for an hour's ride and it had fallen to 33%... About 30 mins after I got back it went up to 55% and is now at 56%. I fully expect it to keep rising as this has happened before. I've kicked GPS into touch unless I'm doing an activity. I even manually set the time after my last reset plus one and avoided letting the GPS do it. I have all the other settings either off or as low as possible (Brightness 10%). That had seemed to make a difference and I thought maybe I'd cracked it, but no... And to end this, the 56% has just risen to 58% for no apparent reason. I'll keep you posted