I've heard there is a difference with these types of reg/rect's,particularly: shunt type and series type.
Does anyone know the Pro's or Con's of these two types ?
As I understand it, the shunt type shorts the output incrementally to bring down the system voltage. The series type would gate the output only allowing what was demanded to pass to system. I believe both these types on our bikes need the field coil to get max voltage and current all the time. The risk is that the field coil overheats and ruins the winding insulation, as it wasn't designed to operate that way.
The best type would be neither of those. But, rather to control the alternator output power, by controlling the power to the field coil electromagnet. This varies the strength of the magnetic field according to the demands of maintaining battery voltage. The alternator makes only the power needed, relative to the RPM it spins. And powers the field coil only as needed.
The field coil CAN be controlled with silicon devices. ( I don't know which brands or offerings work this way.) But, they all use up some power all the time to do their work switching currents on and off. The stock regulator only uses power when there is excess voltage in the system to hold a weak electromagnet contact away from the full power contact position. This means the battery is at full capacity and doesn't need or want more power. If for some reason the electrical loads are extremely low, even the low power mode can overcharge a full battery when the RPM is high. The stock regulator then uses power to completely disconnect the field coil and stopping all output from the alternator, thus keeping the battery from any overcharge harm. The stock regulator is essentially a three position switch that is activated based on what voltage it senses at it's terminals. It is a simple device, but with excellent and efficient engineering, and the only bit that can wear out during use are the mechanical contacts. Which should probably be dressed and spring preload re-adjusted (properly) every 30-40 years or more depending on battery abuse patterns. Lastly, the stock regulator has selected components with temperature coefficients matching the battery charge requirements at different battery temperatures. When the battery is hot, full voltage basis is different than when the battery is cold. And the battery can be harmed if the voltage is not corrected for that temperature variance. The stock regulator complies with this in operation. I don't know of ANY aftermarket electronic regulator that has this feature. But of course, I don't know about them all, and have never needed to buy one as the old but proven design still works admirably on all my SOHC4s.
I spent 30 years in the electronic industry designing circuits. I could design an electronic regulator for this bike if I felt the need to do so. But, since I don't need the profits from selling or reselling such a device, I don't want to, especially since the stock one works so well for me. While Honda did switch to an electronic one for later bikes. They also changed the means of generating power in different ways than that of the SOHC4. The stock mechanical design was abandoned because electronic devices can be made cheaper than electro-mechanical regulators. NOT because they are necessarily "better", but because of profit margins in components, testing and production adjustment costs. To make a mechanical type Voltage regulator today, while doable, would cost far more than the cheap regulators available today made for a price point rather than tailored to function in the best manner for a specific application. Who is going to test them for correct operation in all environmental conditions besides "look the battery charges, must be perfect, let's go ride!" (until something else fails.)
