Tuesday, April 30, 2013

Alternator Regulator-only???

Now that the Small Engine Controller seems to be working well, I have been playing with this idea of an Arduino based Alternator Regulator - just the regulator with none of the Engine control capability.  Myself, I would use this in the Mains alternator replacing the fixed voltage Truck regulator I put in several years ago - after finding the existing Smart REgulators were not that smart, and would keep dropping into Float mode part way through charging the battery.  I got tired of stopping the boat, turning off the engine and restarting, just so that the 'smart' regulator would actually charge the house battery....

Here is a 3D photo of what I have mocked up so far:


It is sized to fit inside a dual SSR heat-sink.  My idea is to mount the TO-220 packages onto the heatsink, using screw holes in the PCBs to gain access.  Prior calculations show this will be a massive overkill, as the way the FETs are being driven there really is very little switching loss.  But such a heatsink does make a well protected package.

Currently, have the following features in the design:


  • Monitor Volts, Battery temp, and Alternator Temp.  Adjusting as needed.
  • Monitor Amps - allow for precise capacity reduction say for small DC generators, but also gives another way to decide transition between different charging modes (ala, Exit ACCEPTANCE phase when amps reduce to 2% of battery capacity) in addition to time-outs.  Maybe make this optional, as it would require an external amp shunt be installed.
  • 3 stage charging, optional 4th 'overcharge' mode for AGM batteries.
  • Feature-in input - can be used for verity of things: selecting Equalize?  Reduce alternator output?  Other???   It would even be possible to have more than one input into the regulator, via simple resisters.  (It is how I do local switches on the larger engine controller)
  • Feature-out output.  Low driving signal that could be used to drive a ALT lamp when there is a fault?  Or???
  • Configurable to support 12v to 48v systems.
  • Configurable to support P-type alternators (High Drive) in 12v systems.
  • Configurable to support N-type alternators (Low Drive) in 12v - 48v systems.
  • Could drive very high amp alternator, or even more than one?  FETs will support 20A+ of field current.
  • DIp switch, or jumpers for selecting predefined profiles - or custom one.

Changes from the integrated controller would include dropping:
  • All engine control and monitoring functions.  Just an alternator regulator.
  • Switching from one-wire temp senders to 10K NTC ones.  But not decided on this one.  Part of it is I found a source that makes the NTC probes already in a copper sleeve!
  • No remote panel.  (Hum - wonder if a CAN bus would be possible???  That drives NMEA-2000!)
  • High Drive limited to 12v only systems.






Is anyone else interested in something like this?







UPDATE  Summer of 2014:  Did move forward with this project, see full details here:
           http://arduinoalternatorregulator.blogspot.com/





4 comments:

  1. Is there a way to detect that too much power is being drawn off of the small engine and to slow down how much power is being drawn?

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  2. Kyle, Hello. If by 'slowing down how much power is being drawn' you are asking if there is a way to limit the amount of power being drawn from the engine by the Alternator, the answer is Yes. Because I monitor (and regulate) both the Volts AND Amps, I can calculate the Watts, and hence limit the total load being placed on the engine. It was one of the core functions of my integrated controller (regulator and engine controller) - to be able to regulate the watts. I carried that capability over to the stand-alone alternator regulator.

    So, if you have a very large Alternator on a small engine, you can configure a max limit to the number of Amps (and/or Watts) that the regulator will allow the alternator to produce, and hence not overload the small engine.

    Is this what you were asking?

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  3. Hi, this is exactly what I am looking for. The regulator on the alternator in our boat died recently and I was looking at designing an Arduino based regulator from scratch but no point in re inventing something that may already work. I am looking at a very basic control with voltage regulation and current limiting for 3 stage charging. Have you done any further developement on this project over the last year??

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    Replies
    1. Wonderful! And yes, have made progress - see here: http://arduinoalternatorregulator.blogspot.com/

      Just completed a group-build, and have some left over PCBs with a few parts mounted. Would be wonderful to have another Arduino-head playing around with this and improving it. Drop me a line with your Email address at mvVikingStar@gmail.com if you are interested in a board!

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