I googled the same problem, but on Lumia 920. I found the answers on microsoft answers and one of the member says that the problem with random battery draining and overheating was gone. The solution was reinstalling the phone fw with Nokia Software Recovery Tool. Detailed explanation below :
I think i already solved this issue (at least for mine . . . give it a try and post your update if this works for you). I think there is a flaw in the manner updates are downloaded from the servers be it OTA or via Nokia Retail Updater.
What i did is that I deleted the previously downloaded Black FW in my PC which I used in reinstalling in my L920 countless times with same issues/results. Downloaded it again at the time where my internet connection is at fastest and stable (in my case 3mbps at early morning) to ensure a flawless transfer of data but this time I used the Nokia Software Recovery Tool. Just go to the same process and viola . . . for 6 days now I'm having no issues with my L920 and a battery life of 2 days for normal usage.
Maybe this is the reasons why the causes are random, some have issues with gmail, whatsapp, outlook, games, gps and for me the MS account. The issue will depend on what part of the update/transfer went wrong . . . well as i said with me its the MS account.
Now my MS account is set on "as item arrives" and no issues with the following apps
connectivity tiles
pdf reader
flashlight
converter lite
battery doctor
here city lens
here drive
here maps
nokia cinemagraph
nokia creative studio
nokia screen beamer
nokia smart cam
office one note
panorama
outlook & gmail account
Syncing is also a breeze . . .before it takes forever! And will load more apps from then on . . . hope this helps and solve yours . . .
Source : [answersmicrosoftcom]/en-us/mobiledevices/forum/mdlumia-mdsettings/nokia-lumia-920-overheat-and-battery-issues/c54b5210-53c6-4eb3-8dfb-f16b7fc7d119?page=9&tm=1435891091089
Is the solution worked with lumia 925 since both of them almost have same hardware?
I am ask this question because I planned to buy used lumia 925 soon, because I loved the camera peformance. I am afraid if the overheating and bettery issues still exist in this year.