Micro CoGen.

A while ago (Yeaks, several years ago) while working on my DC generator controller the question came up:  What was the reason for so many High-Drive type alternators, esp given that from an electronics stand-point is is so much simpler to design around low-drive  (being able to use NPN trans or N-Channel FETs).  Today I think I might have come up with a reason:  Flyback

With high-drive config the flyback snubber directs the current into GND.  While with a low-drive deployment, that energy is routed into the + side of the battery - creating more line noise.

Seem plausible?

Hello.   Has been some time that I had anything to post, but though this might of interest.  One of the longer term goals of my DC Controller project (http://www.microcogen.info/index.php?topic=2941.0) was to look at how different configuration options might impact overall efficiency.   By using the EGT as a control point proxy (consistent engine loading / output at the same RPMs) I 1st am looking at the difference between a mid-frame alternator spinning  around 6,000 RPMs vs. a very large frame one spinning at 2,600.

As shown in this graphs, Alternators are typically more efficient at lower RPMS: 





Last winter I swapped out the existing 130A alternator (Leece Neville 2700 series)  using a 2.5:1 drive ratio for a larger frame 200A alternator (4800 series) and a 1:1 drive ratio.  Here are the results (remember this is a 12v 'system'):

As a baseline using the 130A alternator I recorded the following:
       Alt:           135A using 2.5:1 drive ratio
       RPM:        2,550
       EGT:         943f
       Output:    1,610W

Swapping out the larger Alternator, changing the drive ratio and then increasing loading until EGT was back up in the 940f range; indicating the engine loading / HP being produced is the same as when driving the 130A alternator.   I now get:

       Alt:            200A using 1:1 drive ratio
       RPM:         2,580
       EGT:          944f
       Output:     1,920W


A 19% increase in DC generator output from the same engine loading.  More details here:

http://mvvikingstar.blogspot.com/2015/05/improving-dc-generator-efficiency.html

--or--

http://tinyurl.com/ktqjq5h


Perhaps next winter I will try to dig up a  Desno "Hairpin" Alternator from a junk yard and see what that gives me.  But for now, am very happy with the increased overall system efficiency this change represents.

-al-

I had a chance to review postings in Microcogen forum looking to see if there was a kind of 'best way to get a 48v alternator' agreement, but I am unable to find that.  I see posts around maybe using the 555, and questions its efficiency at 48v vs. 24v.  I see post of folks suggesting two 555's in series to get 48v.  Some about large frame Leece Nevilles with external Diode packs, and perhaps a re-config of the stator.  As well as opportunity buys of manufactured configured 48v alternators. 

So here is my question:  Given all that is known here.  If one is looking to install a 48v capable Alternator, say in the 50-100A range, what would be considered the 'best practice'.  Best practice being  a balance between cost, efficiency, and availability.  One that will not break the bank, rely on being at the right-spot at the right-time, and does not require too much magic.  (ala, likely external Diodes will be needed?   But if one needs to hand-wind the stator, well, that seems over-the-top).

And for those who have deployed 48v alternators, what did you do and how is it working?

Thanks,
-al-

Question for the group:   This winter I am doing some work on my DC generator, getting it ready for next season.  One thing that has bothered me was the small Kubota EA-300 (and EA330) engines have no cooling water temperature regulation.  The Radiator and Fan sit on top of a hopper cooling the cylinder with coolant thermal cycling up and down.  There is no way to control the engine temp - though I suppose one could cover up part of the radiator blocking air flow....

In my marine deployment the radiator has been replaced with a sea water heat exchanger and the same situation:  No engine temperature regulation.  With the engine controller monitoring everything I have no worries of overheating, however, it runs cool..   Or at least cool compared to what I kind of expect.   During operation under load I see temps typically in the 140-150f range.  This is with 50-60f sea water.  To get to the 180-190f I guess I could head South, sea water around 80f or so would get close!

Given the little Kubota was apparently designed for a wide range of operating temperatures, including I have to expect running cool, I am wondering if this is an area I should put any effort into trying to 'improve'.  Adding some external bypass for the sea-water around the heat exchanger to bring the engine temp up to say 180-190f independent of sea water temp??

What ya all say -

• Wow, what a brilliant insight, and here is here is just the part you can use.         -or-
• Man, get a life.  The engine was design for this, and any 'improvement' you make will just be a wasted effort.
  

Thank you,
-al-

I thought I perhaps should start a new topic for he Stand alone regulator, as opposed to continuing to tack onto the integrated Engine controller and Regulator.  Though they are related - in that they use the same core regulator function, there are actually separate projects.   So, here goes!

Yesterday we picked up a stack of part that have been accumulating at a friend's house in Friday Harbor. Among them were the parts and the PCBs for the regulator!



These PCBs cure do look Royal: with their Purple color and gold plating!  With the removal of Tin-lead plating, seems folks are working to get a good alternative, and I am guessing this Gold plating must work well?    I am looking to mount the PCB in the gap in the heat sink to the left.  The Heatsink is a bit of an overkill, but I think between it, a nice plastic cover, and conformal coating on the PCB it will give a tidy package.  And this is a tight board, mostly because I tried where possible to still use through hole components, to make hand soldering easier.  But even so I had to go to three SMT parts, including the dreaded INA-220!  Oh Well.   And, that small PCB the pencil is point it is actually a wiring-assistance to connect the NTC temperature probes to a CAT-5 cable for the Bat and Alternator temperature.  I had better cut way back on the coffee the next couple of days I think!  Will be doing some family traveling soon, so likely will not be able to bring one of these up until mid July.  But am looking forward to seeing how things work out.


And to kick this regulator only thread off, here is a kind of high-level summary of the key features:

• Support 12, 24, 36, or 48v batteries
• Supports 12,24,36, or 48v field - independent of battery voltage
• Support N or P type alternators with no hardware changes
• Monitors Voltage as well as Current, to allow for smarter transactions - primarily preventing early exiting of Acceptance phase while battery is still undercharged.
• Also allows for setting limit on engine load, e.g. when trying to drive large alternator with small engine.
• DIP-Switch selection of 8 predefined charge profiles, ala FLA, AGM, etc.
• Temperature probe for battery and Alternator - battery temp compensation and alternator temp limit
• Feature-In and Feature-Out ports, currently being use to drive external 'dash lamp' and provide ways to reset-to-initial configuration and/or select EQUALIZE mode.
• Ability to fully customize charge profiles via ASCII commands - stored in EEPROM
• Serial port for monitor status and/or changing configurations
• Bluetooth port for doing same wirelessly
• Sync port to intelligently communicate between two alternators chargings same battery (e.g., twin engine installation in a boat)
• Open Source design, hardware and software (non-comercial), allows for fully configuration and modification if desired.

Someone will also be working on some applications to host the Serial communications (via Bluetooth and/or serial port) on PCs, Androids, iPhones?  to allow for monitoring of the current status as well as simplify configuration changes.

And as some of these things get proofed out (esp the new FET drivers), I will likely roll them back into the full Engine Controller / Regulator project.

About 1 year ago we installed two 245 watt Solar Panels on Viking Star.  Before doing so I tried to get information from others who had panels installed about their performance, but all the 'information' was just gut feels.    Well, I have been tracking our panel's daily production via the Morningstar MPPT controller's data logging capability, and today I sat down to work up a 1 year summary. 

Some background:
  O We installed two 245w panels, mounted largely flat and with no tilting / aiming ability.
  O We are using an MPPT type charge controller
  O We are on a boat and have been in the Pacific Northwest the whole year
  O Our 'Cruise' session is from March 1st to November 1st  (Nov..Feb we come into a dock somewhere)

This last point is rather critical, it means 8 months out of the year we need to generate all electricity ourselves - either by the 270A alternator on the main engine, the Kubota DC Generator, or the Solar Panels.   We only have access to cheap shore power from Nov..Feb (when we can really use it to offset heating costs).

And for results:  looking back over the year the actuals came within 2% of modeled (predicted) output.  During our cruising season (March through the end of October) we produced an average of 124.7Ah/day (12v, Boaters like to talk AH/s, but I really tracked in Watt/hrs), saved 245 hours of run-time on our Kubota DC generator, which results in a raw ROI of 5.5 years.   Figuring in the Federal Tax Credit it drops to 3.9 years.


I have more details here if you want to see them: 

http://mvvikingstar.blogspot.com/2013/06/a-year-with-solar-or-is-it-wait-until.html 

-or-     http://tinyurl.com/ln4sntw


-al-


Viking Star
45' Monk Sr. / McQueen
mvVikingStar.blogspot.com

I have a DC generator setup in out boat, it is a Kubota EB-300 (EA-300??) driving a mid-sized frame alternator.  A VERY common issue with these Kubota/DC generators is overloading of the engine, in some cases bring them to a very early demise (like 100's of hours).  A primary feature of the small engine controller and regulator I have been working on  http://www.microcogen.info/index.php?topic=2941.0 is the ability to closely control the amount of load placed on the engine (by monitoring both Volts and Amps produced by the alternator, and regulating on both values).

Another feature of the controller is an EGT sensor.  My intention is to monitor EGT to determine when the engine is running at an appropriate full load, vs. running overloaded. Could even have the controller 'regulate' to this value and self optimize for maximum production / min run time.   To date (the past several years have been using a simpler  commercial regulator) I looked for overloading by looking for Black Water out the exhaust. And  I would move the governor a small amount and see if the engine could respond to changes.  With an EGT probe I want to do better and here is my question:  What range of EGT should I expect for an appropriately fully loaded engine?  And at what point should I consider I am moving into overloaded?  There are lots of google hots on the web, but they are all from Diesel pickup guys - larger engines, loafing along except for short bursts, and these all have turbos as well.   Any idea what I want to see for a small non-turbo engine working near it continuous HP rating?

And where should I try to locate the EGT probe its self?  In my setup the exhaust makes a 90' bend soon after leaving the engine and then has a 12" raiser.  The 90' bent has lots of meat to drill and tap, but I wonder if I will be getting false reading being so close to the exhaust port.  Somewhere I picked up it an EGT probe should be located 10" or so from the exhaust port on non-turbed engines.  Any advice?  There is another set of bends 12" down the road, would that perhaps be too far away?


Finally, though I have not yet done a multi-hour generator run with this new controller in place, I did noticed during a 30 minute run the engine temp only raised to 137f   Was still climbing when I stopped, but very slowly and was so far away from 180-190f.  These small engines have no temp regulation in them, even when air-cooled, and I am sure they are engineered to work over a WIDE range of temps, but am wondering if 137f just indicates too much cooling (we have a sea-water heat exchanger in place now.  52f water these days.)   Do I need to be concerned about this 137f temp, maybe adding some type of sea-water bypass around the heat exchanger.  or am I likely OK.

When not playing the Arduino based Alternator Regulators I get to do other fun things.  One I have been working on over the past month was digging into an interaction between our new Magnum MS2000 inverter and Splendine washer/dryer.

Bottom line:

• The Splendide XC2100 Washer/Dryer and the Magnum MS2000 inverter do not play well together.
• Problem is a bit of both sides fault - with the cause a well know issue in AC Power systems.
• Problem can be corrected with addition of 50uF motor Run Cap

The Splendide presents a rather complex / mixed (inductive and traditional Power Supply) current load during its washing cycle, and the Magnum inverter is not able to keep up with the demands.  Lots of gory details, scope photos, and a nice drawing of the solution here:  http://mvvikingstar.blogspot.com/2013/03/summery-and-conclusion-compatibility.html


I know most off-griders tend to use inverters larger then 2000w, but perhaps this information will be helpful in some way to even larger inverters deployments.

-al-

As winter is approaching I have more time to Play with things and have picked back up on a project to provide more control of our Kubota / Leece Neville / DC Generator / watermaker.  (referanced here: http://www.microcogen.info/index.php?topic=2257.msg27611#msg27611)

This all started out from me wishing to have finer control of the regulator, managing not only the charging voltage, but also the total load placed on the 5Hp Kubota with the overall goal to lower the run time.  In order to do this, I needed to monitor the total Watts being produced by the alternator and adjust the Field to keep the motor fully loaded at all points of the BULK charge state.

Over time I this project, as many do, grew to include not only the alternator regulation function but also basic Kubota start / stop capabilities.

As it stands, key goals include:
- Traditional 'Smart' multi-stage alternator regulator
- Adding Amps sampling to manage total load on Kubota  (The Alternator is able to stall the motor at Full On, so it always running at some reduce state.)
- Basic Start / Stop function of Kubota
- Throttle Management
- Fault monitoring and management
- Remote Display and switch panel


I selected the Amtel / Arduino development environment and have completed the initial hardware design.  My next step is to build a prototype and begin the software, as well as hardware refinements / corrections.

All are posted at: http://smartdcgenerator.blogspot.com/

I would welcome any and all thoughts on this before I spend more $ on it (specifically sending off for the PCB - as that is a bit harder to change once it arrives).  There are .pdf's of the schematic and PCB as well as Gerber files for the pcb.

Thank you,
-al-