This is the standard equipment. With the optional capacitor, the engine will continue to run in case of battery failure. However an engine restart in the air using the electric starter is not possible.
Each ECU has its own set of Hall sensors.
Should an ECU fail while flying and the engine stop then a switch in the cockpit allows selection of the alternative ECU and a re-start in the air.
Both circuits should be tested before take-off.
The same advantages as diagram II, however 2 batteries are now charged by a double alternator. This alternator has two outputs from 2 sets of windings each delivering 50% of the power of the standard alternator for the same weight and dimensions If one set of windings fails the 50% remaining output provides sufficient power to proceed to an airfield.