In SX Microcontrollers, SX/B Compiler and SX-Key Tool, sdtrent wrote:

Ken,

Your power generator looks great!  It is a work of art.  I would enjoy reading a full article on the project.

I suspect that your battery is closer to 10 Ahr rather than the 10 mAhr noted in the schematic of the LM723 voltage regulator.

Are you planning on taking the next step and replacing the LM723 with the SX for regulation of the field current?  In theory it should be rather simple.  

Just keep the voltage divider read the voltage with the SX.  Replace the 2N3055 with a logic level MOSFET controlled with the SX (buffer with an ICL7667 style MOSFET driver if you want very fast edges) and PWM the field coil.  A loop update rate of 100Hz to 200Hz should be plenty.  

In addition being cool and reducing the parts count, you would also get more run time.  You would save the power lost due to the base current of the 2N3055 as well as the associated I*Vce losses.  You might even be able to eliminate the 16 ohm resistor in series with the field coil for additional power savings.  

You might want to throw in a one-wire temperature sensor to make sure the alternator is not getting to hot at full load.

I also wanted to throw in with Guenther. The best way to accurately count short events is to use an interrupt on level change (edge).  Otherwise you are guaranteed to eventually miss events unless your time between samples is shorter than the minimum event duration.

Congratulations again on such a well designed project.  I look forward to reading more about the design and build.

-Shane

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