Friday, May 1, 2020


Revised 6/20/2013

Note:  If you are looking for the companion to this - the Stand-along Alternator Regualtor, I have started placing those files in a separate Blog:

After using our Kubota EA300 based DC generator / water-maker for about a year ( DC Generator.)  I wanted to make an improvment.

The goal was very simple:  Shorten the amount of time I needed to listen to the Generator running.   See, being away from the dock for 8-9mo a year we are very dependent on our generator.  And I just did not look forward to the 'suffering' hours of the daily generator run.  I wanted a regulator which would maximize the amount of energy produced for every minute the Diesel was spinning.   I also wished to be able to generate some energy while running the Water maker and provide remote operation of the generator. 

As the project grew, it gained two additional values:  ability to fully recharge the batteries, along with remote automated start/stop.

Limitations of most 'smart' regulators prevents all of these goals - primarily because they manage only the Volts, relying on the self-limiting nature of alternators to manage the Amps. (Though some do a crude attempt to manage Amps produced.). A major design point of this project is the active monitoring of BOTH Voltage and Amperage. By doing so I will be able to meet the charging needs of the batteries while also maintaining a constant load on the Kubota EA300.

BTW:  If you are looking for a simpler design, one that keeps the key values of shortening Generator run-time and/or the able to fully recharge batteries, see the stand alone regulator on the link above.

This design is done in such a way to be applicable to other small engine control deployments.  With or Without an Alternator and/or Water maker.  Key features include:

Overall Features:
  • Local Controller and operating switches with optional remote display / switches.
  • Supports system voltages (Starter, throttle control, etc) of 12 or 24v.
  • Support of Alternator field and battery voltages up to 48v systems.
  • Alternator voltage support is independent of System Voltage - as 12v system can manage a 48v alternator.
  • Driver to enable external pump, ala HP pump for watermaker, or circulation pump for co-generation deployments.
  • Open Source Firmware and hardware for ultimate customization
  • Easy attachment of diagnostics console for easy firmware updates as well as detailed monitoring and logging of system operation.
  • Wide range of configuration available, modes of operations, checks preformed, features included.

Engine Management:
  • Selectable Auto Generator Start-up (based on battery voltage)
  • Auto stop after charging is completed
  • Warm-up and cool-down periods w/o alternator load.
  • Active throttle speed control, adjusting engine speed to match current loading.

Alternator Management:
  • Fully configurable 3-stage Alternator regulation with soft ramp of initial power on.
  • 'Over Charge' (or 4th stage) support for AGM batteries.
  • Battery Temperature Compensation and adjustment for all charging voltages.
  • Reduced total charge time by capturing wasted engine capacity during early portions of charge cycle.
  • Precise measurement of battery voltage,  including  negative lead to accommodation any common ground line voltage drops.
  • Alternator charging actively managed by measured battery voltage, charging current, and total load placed on driving engine.
  • Adaptive alternator reduced power mode to support simultaneous driving of other loads, ala water pumps, hydraulic pumps.
  • Charging rate reduced under excessive EGT, engine and/or alternator temperature conditions. 
  • By actively managing Voltage and Amps, larger framed alternators turning at lower RPMS can be utilized resulting in upwards of 10% greater alternator efficiency.

Fault Detection:
  • System fault monitoring:  Over temperatures (Engine, EGT, alternator, battery), voltage, amps.
  • Broken sender / wire check for Oil pressure and Cooling Water Flow Senders.
  • Fail safe protection:  Watchdog timer, hardware crow-bar for over-voltage
  • Software self-checks for incorrect configurations, and internal operating errors.

And some likely future enhancements will include:
  • Auto Start quite period holds off (with optional RTC added)
  • Lifetime recording of total amps /  watts produced by alternator, hours of operation, etc.

The project is base around the Amtel ATmega328 CPU configured using the Arduino development environment.  All parameters and features are fully configurable  with a wide array of options.  Features may be disabled if not needed.   

All works are being released under the Creative Commons licensing agreement, with the only restrictions around commercial use.  I have selected the Open Source KiCAD tool for Schematic capture and PCB layout and posted those CAD files.   Links at the top of this Blog provide details of each portion of this project.  Click on the Link-to-Files area to download the schematic and well as PCB layout and parts list.

The Design Elements section goes into more details of each sub-segment.

And for an ongoing list of status / issues click here:  >>> STATUS <<<

Comments and advice are always welcome!   It is my hope this project can be the basis for others works in intelligently controlling small engine deployments and generating systems.