The easy way (and the common factory way) would be to simply use a 3 phase bridge rectifier and zener and transistor to shunt excess power to ground to maintain 12V. I was thinking of using schottky diodes to gain a little more voltage at idle, although now i don't think its necessary after measuring the original 1970s rectifiers voltage drop at 2.5V with a 5 amps load. That is 5volts lost! I believe any decent standard modern rectifier should be less then 2.5V drop. That is already a 20% gain which is more then a $200 rewound stator will get you. Also i am thinking of changing from shunt to linear or switched regulation to prevent unnecessary engine loading and heat dissipation in the electronics.

For interest stake i am thinking of better/more elegant ways rectifying and regulating 3 phase to 12Vdc. I think the best way would be mosfet H bridge arrangement, if there was a controller IC available this might be quite a simple arrangement with nearly no voltage drop? Another possibility would be using thyristors in place of 3 of the 6 bridge diodes, this might be the most simplistic and rugged approach, i found a simple schematic someone else drew of this.

 

Common 50 - 100 volt diodes of today standards would show around .6 - .8 volts forward drop at 5 amps.

That will pick up a considerable amount of lost power.

Shottky diodes would cut those loses again by about half. That's where I would start for picking up extra power at idle.

 

Welcome to AAC. With regret I have to close your first post.

The owners of All About Circuits have elected not to allow discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

This thread is against the AAC forum rules, Chapter 6, as seen here:

6. Restricted topics. The following topics are regularly raised however are considered “off-topic” at all times and will result in Your thread being closed without question:
• Any kind of over-unity devices and systems
• Automotive modifications
• Devices designed to electrocute or shock another person
• LEDs to mains
• Phone jammers
• Rail guns and high-energy projectile devices
• Transformer-less power supplies

This can be found in our Terms of Service (ToS)

Motorcycle modifications still fall under the category of automotive modifications.

Here is a site that may provide you with some assistance: Electro Tech Online

Good luck.