Why does my konkar8a mobile go dead flat over night when even when it has not been used.

There are likely apps running in the background all the time. Make sure you terminate any apps when done with them and it is not automatically syncing or updating. There is probably at least one app responsible. Go into settings and examine battery. It should show you the items that are consuming your battery. One other thing, you should cycle your phone off and on every couple days to allow updates to be completed and to stop apps that are "stuck" running in a loop.