I've had my 1520 about a week and had an issue 2x where I set it to charge overnight (approx. 8 hours) and found the phone not to be fully charged.
The first time was the 2nd night I had it and figured I must have plugged it in wrong, but last night my battery was at 10% when I put it on the charger. I checked it 30 minutes later and found it at 6% despite being plugged in. It turned out my wifi was disconnected and I was downloading a music using the cellular antenna. I cancelled all the downloads, restarted the phone, and went to bed with nothing being downloaded and connected to wifi. This morning my battery was only at 25%. I came into work today and 3 hours later it was at 100%.
I never had this problem with my 1020 and it seems to be specific to 1520.
The first time was the 2nd night I had it and figured I must have plugged it in wrong, but last night my battery was at 10% when I put it on the charger. I checked it 30 minutes later and found it at 6% despite being plugged in. It turned out my wifi was disconnected and I was downloading a music using the cellular antenna. I cancelled all the downloads, restarted the phone, and went to bed with nothing being downloaded and connected to wifi. This morning my battery was only at 25%. I came into work today and 3 hours later it was at 100%.
I never had this problem with my 1020 and it seems to be specific to 1520.