after two replies from the Customer Service I decided to ask if the Community has the same problem as I.
My phone is Lumia 820. Works fine, no problems. The battery lasts for approximately 1.5 day (ypu can say not bad - ok). BUT - after the battery runs out, the telephone switches off (automaticly due to low battery), when I try to switch it on, there is a red battery blinking sign - ok. But If I wait four hours (without touching the phone) the phone not only will switch on but the battery shows bettween 20%-50% and - what is very weird - it is sufficient for the whole day of normal work (phone calls).
Can anybody check this issue?
Yes, I've done tests on the newest software. I've also done "reset to factory defaults" few times.
It was also done by the Customer Service (twice) - the first time they checked only battery and software and said everything is ok (they've held the phone for two days), second time I've described them what they should do (Charge the phone to full, insert sim card, wait until the battery runs out and phone switches off, wait couple of hours (4) and switch on, repeat the test) - they have held the phone for two weeks and said no fault.
It's also weird to me, as the phone, apart of that, works fine.
A moment ago I've performed the soft reset as you said - I switched the phone off, held both buttons, the phone vibrated, waited a second, switched the phone on. Before the reset battery showed 21%, after the reset now shows 61%.
Is this a problem with: the battery, the software or the phone?
None of my friends has such a phone, so can anybody perform the test?
The system used to approximate battery level in phones is very simplistic and not at all accurate. All it does is to measure the voltage and approximate level from battery. Voltage level in the battery will temporarily dip after a discharge episode and will recover slightly if left to rest for a while. Perhaps this is what you are experiencing.
@cjlim: I can understand what you mean, but there is a very huge difference between the battery indications. And it's not only indications as the phone can work a copule of hours more.
I can imagine that if my phone/battery was working properly, it could have been working for few hours more.
Maybe my battery has so non-linear behaviour, that it needs a reset after a small discharge.
You need to drain your battery followed by a full charge without interruptions. Due to the non linear behaviour of your battery, it may take a while to fully drain.
@cjlim: I've tried that a few times.
I'll try this recalibration few times more with a combination of this soft reset. I'll write the result of this test probably after a week or so (need some time to discharge the battery).
During my last week holiday I've performed some test and there is no improvement.
On friday evening the baterry showed 15%, I've put it on the table and gone sleep, in the mornig phone was switched off (automatic switch due to low battery). I've switched it on (without any additional action), the battery indicator showed 69% and battery worked for 12 hours until it run out.
I have no ideas what to do. I don't even now if the problem concerns battery or phone. Maybe I'll buy cheap battery replacement and try on it. But what then with a guarantee.
Has somebody from forum encountered the same problem?
Once I've found an advice like this:
1. Update your phone.
2. Charge the battery (fully - leave it for a couple of hours)
3. Restart phone
4. After turning the phone on, switch airplane mode for half an hour
5. Maybe it will help
Unfortunately it didn't help me. But maybe you will be lucky
I don't even know for now if the problem concerns battery itself. I also don't know if changing the battery may help.
If the process, mention above will help or you find the solution or reason of this behavior please tell me.