I recently updated my Nokia Lumia 800 to the latest build, 1600.2483.8106.11500.
I’ve been keeping an eye on the battery capacity of my Lumia 800 following the reported battery charging issues using the phone diagnostics (which can be accessed by entering ##634# on the phone keypad, then from the list of applications afterwards) and noticed that following the update to the latest build, the reported full charge capacity started dropping. Initially it was around the 1350 mAh mark, following one full charge it dropped to about 1250 mAh, following the next it dropped to about 1140 mAh. Over the next couple of days it rallied a little, settling eventually at about 1180 mAh.
In reality I wasn’t too worried by the apparent drop in charge capacity, especially as the runtime following a charge was a good step up on what it had been before the update, but was concerned enough to drop Nokia a quick e-mail to ask them about the issue in case it was something they’d not come across before. My phone’s reported runtime was also lower than others in the office were reporting for theirs and I’ve seen some experiencing similar issues with their Lumia 800s on the Nokia forums.
Nokia’s support has been excellent. Following my initial e-mail to them, I had two very quick responses by e-mail asking for a few more details, followed by a call offering to collect the phone to run some diagnostics on it. Following a quick conversation with Robert however, it looks like I won’t need to take them up on their offer…
The solution in my case was to stop the tasks running in the background on my phone. After stopping the background tasks (go to settings, then slide one screen over to applications, then select background tasks and stop anything that is showing as running), RAC Traffic and one other in my case, I rechecked the battery diagnostics, and not only showed that the current being used had dropped by about half, but the reported battery full charge capacity had returned to it’s original state of over 1400 mAh.
Quite why a couple of running background tasks were influencing the reported full charge capacity of the battery, I’m not quite sure, but the method seems to be a reliable way to return the reported capacity of the battery to its full value.