I am designing my electrical system for my Kitfox SS7. I have a Rotax 912S and I am installing a master cut off relay for the battery. I have looked at several wiring diagrams others have used and see some people put an additional relay in to cut off the alternator power. On conventional aircraft they cut off the field wire to stop the output of that device so no power even exits in the cable coming out of it. On the 912 it installs a relay to stop the output to the battery. I am thinking this is really not doing much and is it really needed? Unless the relay is mounted right next to the regulator to eliminate the presence of a high amperage hot wire running in your engine compartment, what advantage does this really have? I was thinking of running the regulator directly to the battery which is already protected by the master cut off... Anyone have any thoughts on this and am I way off track? Your thoughts please... Ken