Re: my lumia 1520 heats up in the top left corner, what should i do ?
This is normal operation for any smartphone.
Gaming is the most taxing thing you can do. Game plugged in to wall charger of at least 2A output to preserve battery.
An approximately 25 minute 1080/30 video brought me below 50% battery level and heated up my 1520. Once again, normal operation. No chance my previous phones, iPhone 4s (not capable) and Galaxy S3 could have completed the task successfully.
My suggestion is employ daily battery saving measures. Check your Battery Level app for apps running in the background. Change email account sync settings to once daily/manual. Shut off Location, Bluetooth, WiFi/Cellular when not necessary (i.e. taking video and some games), Nokia/Microsoft feedback options, and Camera auto upload (be sure to switch back on to maintain OneDrive bonus).