Solving the electrical systems depth in x-plane is a deceptively nagging problem that requires one to ignore most all of x-plane electrics save the battery charge. and TBH, it really is the only 'system' in a small GA. You can tie a few circuit breakers to default datarefs but that usually still leaves a lot left. For example, alternators commonly have a field winding tied to a voltage regulator...so there are TWO ways to disconnect a generator (THREE if you want to fail the voltage regulator)...via the generator switch (which disconnects a relay) or the field switch / fuse, which disengages the voltage regulator (not modeled in xplane). In addition, most avionics work on a voltage range...so when the alternator goes down, you will have 'x' amount of time before the battery drains below the minimum level to drive a device...and not all devices have the same voltage range, so you may lose one device before another and x-plane doesn't do this by default either. You need a battery model (different for Ni-Cad vs. Lead-acid), a charging model and a discharging model to get really accurate......but really, what user simulates alternator failure in a single GA or cares if an instruments dies in 10mins vs. 15mins. Is it that we enjoy knowing its there? Most aircraft don't have truly accurate systems and most users don't know it because they always operate the aircraft in a predictable manner and as long as the author makes sure things look right down that path and users don't deviate too far, they're golden. Most developers who claim they have "realistic systems" don't have truly realistic systems....but what they do have is "realistic enough for most folks to enjoy them" systems and there is something to be said for that....BUT at the same time, having truly realistic systems satisfies most all types (there are folks who claim they want accuracy but then complain when they actually get it) so there's something to be said for that too. I think in the end, a product follows a developers preferences and standards and folks who share in those can share in the enjoyment of that product for what it is. TomK