Yes, now it is totally understood that the analog mic was causing all this trouble. Perhaps this note for other analog inputs while having analog mic should be somehow highlighted in the documentation. Anyways, after loosing some hours of sleep I am pretty glad now that the wled is up and working in a very stable manner 
As about the battery indicator I am about putting an additional circuit piece that will show me the full/empty battery states with a two color green/red led.
Perhaps this will do the job:
If you have any other small size schematic to suggest please recommend.