Dragonfly wrote:Yet it appears the alternator overloads and heats above the critical temperature.
And, with my humble electronics experience, I see no problem whatsoever to get stable and conditioned 5V supply from the KERS battery even if it has several tens of volts rating, or even more.
The Alernator doesn't overload the circuits at high temperature though, it might actually under power them!
The components of the alternator just fail under the heat generated.
The MGU on the other hand can overload the electrical circuits of the car because it works at much higher voltages (over 400V??) and is wired to suck more power from the engine. The only way to practically reduce the voltage output from the MGU is to reduce the strength of the magnetic field winding inside it, or install a another DC to DC converter on the MGU.
The current from the MGU is derived from the engine torque transferred to the MGU. Therefore you only want to a small portion of the engine torque being transfered to MGU OR you have another load (KERS) in the MGU being charged at the same time.
So Technically it is possible to use it as an alterantor, but do you you want to use it 100% of the time with fancy controls to change field winding current on the fly and fancy load reduction devices that work in two diffrent modes? KERs mode and alternator mode? I think it is simpler and more reliable to use the tried and proven alternator to power the car electronics.