Norman,
I am pretty sure the modern regulators don´t apply Zener diodes which produce a short to earth above their fixed voltage maximum. These do transform excess voltage and current into heat.
The typical dc dynamo or even three phase car generators need some of the power to produce a magnetic field wherein windings rotate. Rotating windings in a magnetic field produce voltage and current. So in a case when the field is generated by electric power you can modulate the power that goes into the field and so you can limit the voltage that is generated by the dynamo or alternator. This type of generator needs copper windings for the field plus windings where the power output comes from.
Now looking at permanent magnet alternators, you get the field from the magnets which you cannot regulate. So the higher the speeds of the magnet rotors the higher the voltage goes. In long passed times the excessive voltage was sunk to earth by the Zener and went up in heat.
The modern type of regulator for these permanent magnet generators will most likely apply the pulse width modulation PWM electronics. An AC alternator, single or three phase, no matter, outputs a sine wave form AC voltage. Depending on the speed of the rotor, the voltage may reach 20, 30, 40 V , not suitable for your 12 V battery. So the PWM just cuts each sine wave at the point of 14 V along the curve. It does not sink the rest of the voltage into earth, just cuts it. There is certainly some power loss into heat as from any semiconductor apparatus, but no way all of the excess current gets lost in heat. When you look at the regulator that I ordered last night, it can output 35 amps at 14 V . So that would be almost 500 W , you could use that for cooking if all of the power was turned to heat. But in reality the component is only 90x85x28 mm large, so one can guess what amount of power will be lost in operation. Anyway, 500 W is only 3/4 of one hp and we´d be happy to have maybe 150 to 200 W - just one quarter of 1 hp.
Yes, this kind of regulation seems to be undersophisticated but then you get an alternator which has no brushes, no collectors, no flying windings. It is even suitable for in- oil operation like in bevel Ducatis. Once the motor spins the alternator produces power without a battery. But then I guess a battery will be easier on the regulator for cushioning voltage spikes possibly, I don´t know. Those China regulators should be allright with 30 or 40 V at times - anyway, cheap enough to have some on stock.
Vic
Rectifier 14.5 V 35 A
Honda three phase alterator
Honda alternator brushless