Hi Ricardo.

I had a similar problem last year. I had electric_always_available=1 as well. I still lost them after about 30 minutes.

LOU kindly answered my problem here: http://www.captainsim.org/yabb2/YaBB.pl?num=1267897624/15#15 and in the replies that follow.
I was able to remove that line from the aircraft.cfg and I have never lost the avionics during a flight since.

Hope this helps.

Mark