Ok, obviously I did NOT do exactly this, otherwise it would have worked…my bad!
So: I found out both the problem with the alternators failing and the problem with the load only going up to ~70% at full throttle are caused by an incompatibility with the “YourControls” mod (for shared cockpit). With incompatibililty, I mean just having the folder of this mod in the Community-folder ( without having a shared cockpit session active).
EDIT: And if i had read through the previous posts more thorougly, I would have seen that this is already known… facepalm
Edit2: @OkkoAurelian You have been faster with your reply than I was with the edit… I gladly admit that you informed me thusly. 
