Considering the Electric Fan turns ON (low speed) earlier than expected (96C), I modified the logic circuit to accommodate that.
I don't know how much power the radiator fan consumes on low speed.
I think the fan circuit is on a 30A fuse.
So theoretical electrical load would be 12.6V x 30A = 378 Watts on full speed. Not sure, but Low speed could be half that, so around 190 Watts.
I would assume the aero drag would be higher than 190 Watts with shutters 50 % open.
Keeping shutters SHUT and allowing the fan to run on low speed might be more efficient, but the trade-off would be increased wear and tear on the fan motor. Which is why I considered an approach that allows a more gradual cooling.
Trigger points :
Below 90C : shutters SHUT
Above 90C : shutters open @ 25 %
Above 93C : shutters open @ 50 %
Above 96C : shutters open @ 100 %
Fans ON : shutters open @ 100 %
