Hi Adt2015, you can control a power transistor or thiristor from any alternator regulator. I show you the diagram of my alternator type charger and variable power source (Own design. The diagram is free to use). In the case that you build it with a built-in power source, this circuit unlike the traditional ones, the voltage regulator reference is taken from the input and not from the regulated output, so you can also charge batteries from this output + VDC of variable voltage The diagram below is only alternator type charger (With positive regulator the design is facilitated because it does not require transistor Q3): This is the adaptation for positive regulator, which in this case is Delcoremy brand In case you require it, I send you an explanatory image, for proof of regulators to the positive and regulators to the negative. A variable DC power source is required, up to at least 16VDC (The bulb turns off when the voltage is greater than approximately 14.5VDC): Luck.