power outage with key fob

Late last year I had a new battery, which turned out to be the wrong one. New battery on in new year, problem solved. Or so it seemed. I am now experiencing power outage. At first I thought it might have been a security issue as a few times I was sat in the car with the engine off, but with the key just sat in the ignition, where upon the system went dead with the dashboard panel dead and the engine would not start. This happened a couple of times all with the engine starting up after a few minutes. Yesterday morning the system again went dead, would not start and I had to use a battery starter. This morning I could not open the door on the button of the key fob and the panel was again dead. I opened the door using the key and the panel rebooted and I was able to start the car. Upon finishing my journey I put one key in the ignition and locked the door with the key and proceeded to do a system reset i.e. turn the key in the lock to open the window and then lock the door to close the window. I then swapped the keys and redid the reset. Hopefully redoing the coding on both keys. I started the car with one key and then the other to check them. Anyone have any ideas as to what might be happening and what can be done to fix it as I'm just running on guess work.