Thinking about building a small Diesel DC powerplant

[Zeroclearance]

Brian, I posted the link to the Yanmar 2 cylinder.   It is rated at 13.4 HP at 3600 RPM's..   Peak torque is right around 2466 RPM's.

As you know with alternators we don't have to worry about engine sync to get our 60Hz.    That's one of the nice things about using the DC alternators.   My goal is to conserve fuel and get as much power in amperage out if these alternators as I can.    I will drop the engine RPM to around 2400 to 2500 RPM's and install the correct engine pulley to run the alternators at peak output.

I was able to call Balmar,  I spoke with Rick Jones, it was after hours and he picked up the phone to talk with me.   Balmar has introduced a 3 stage Dual alternator regulator  Max Charge 612 -Dual (list price under $500.00)  It allow for temperature sensing for Both alternators AND your battery bank.

[rv_safetyman]

Others have commented that you are cutting it close on power.  400 amps at 24 volts (will be higher but for calculation purposes) is 9600 watts or about 12.9 HP.  I have to wonder how accurate the rating on your engine is.  If done according to SAE standards, that HP is at standard temp and pressure without accessories (won't affect you, since I assume your engine will not have a separate small alternator, but it will have a fan).  If you go up in altitude to say Denver, or worse yet Vail in Colorado, you are going to be short of HP for Max output. 

The alternators have an efficiency factor for altitude as well as I recall.  Perhaps that works in your favor.

Gut feeling, you will not be getting 200 amps out of the unit very often, so maybe you are OK, but you are close.

Jim

[Zeroclearance]

This engine will not have a fan, I mentioned in a earlier post that I will purchase a radiator and electric fan.    Honda Civic radiators and fan assy's are cheap.   The engine will be turning a water pump but that is it.   Yanmar is pretty good with there dyno sheets.   We have to trust the ratings coming into the US for emissions cert.   

Jim you might be right about not getting 400 amps.   But if I get 360 amps at 1/2 gallon per hour I will be happy.   

[OneLapper]

You are going to do plans, pictures, drawings, etc. so us newbies could consider copying right? Please 

Ditto!  I'm also very interested in this project.

I hope that 2 cylinder Yanmar is smooth and quiet enough.  John Deere used that engine in the early 650 compact 4wd tractors, but only for a couple years, then switched to a 3 cylinder.  I hate to say it, but our mechanics would call that little engine a "thumper".

Mark

[TomC]

Once again- a 2 cylinder will be much rougher (read noisier and more vibration) then a 3 cylinder since a 2 cylinder is not even firing.  Even though it appears that the Kubota is built lighter in weight then the Yanmar, I have a truck driver friend that when he sold his big rig, his Powertech 8kw gen using the small 3 cylinder Kubota had 23,000 hours on it-like 920,000miles without overhaul. That sounds pretty robust to me.  Good Luck, TomC

[Zeroclearance]

I received my new 200 amp Leece-Neville alternators on Friday.   I'll take a few pictures and post them later.   These are large frame units.   I was really surprised to see how heavy they are.    They are about 3/4 the size of a Delco 50DN.   

Listening to the conventional wisdom of Tom and Jim and others, including onelapper with his famous quote "thumper" >> I will move to a 3 cylinder engine.    It wouldn't be fun to spend all the time building this thing to hear the pounding of the 2 cylinder.    There is a guy on Youtube who has installed a small 2 cylinder Yanmar in a Ford Fiesta.   The car really rattled.

[Len Silva]

After you get it working, you could develop a load sensitive throttle to control the engine speed.  Then you would have something like the Onan Quiet Diesel.

As I was thinking about this post, I went to the Onan site.  They now have a hybrid system
http://www.cumminsonan.com/hqd/
which looks very interesting (way out of my league, but interesting). It "combines a Power Unit, Inverter, Transfer Switch
and coach batteries into one cohesive system that automatically and seamlessly
powers your motor home efficiently and effectively."

No idea how much it costs, and I don't want all the fancy electronics myself, but it does look pretty cool.

[bevans6]

To my way of thinking it's basically what we are talking about.  An integrated, highly controlled version of a DC power plant supplying power to batteries and an inverter, to supply both 12 volt and 120 volt power seamlessly.  Connected to the pedestal - auto transfer switch puts the Inverter in charge mode for 12 volt supply and supplies 120 VAC to the coach.  Generator on - supplies power to the inverter and keeps the batteries topped up.  Generator off - batteries supply the inverter.  Inside the coach - never a dull moment!  I want to take it a step further and add the bus engine alternator to the choices.

This makes me wonder if inside the Honda and Yamaha inverter generators if they develop DC power first, then convert that to AC.  It would be one way to do, I don't see any reason that developing AC power first would be more efficient.

Edit long after the fact but I don't want people thinking I am dense...  Alternators of course develop AC first, then it is rectified to DC via the rectifier diode packs.  usually 6 diode packs.  The fancy Onan mentioned above actually says in it's literature that it develops AC to the inverters, just not necessarily 120 volt 60hz AC.

Brian

[Zeroclearance]

I think the key to good bonedocking power is to start with one or two good inverters.   If you shop you can find new Xantrex/Trace 4024's for $1500 to 1600 each.    Outback and Magnum are other options.   My goals are to have one SW4024 running off my 50DN (engine) charging one battery bank and adding the "new" Hybrid 400 amp system for the second SW4024, and a second battery bank.   This last bank will have solar added.   I will keep my 20KW genset as a backup unit.

[Len Silva]

I think that is basically what they do.  They start with AC, rectify to DC to an inverter and back to AC.  The only reason for doing that is that the engine does not have to run at a strict constant speed, thus lower power requirements can save a little fuel.

We spent the night once with friends that had the Onan QD.  It was quiet but I found the speed changes with load to be very annoying.  I much prefer the constant speed when trying to sleep.

[TomC]

Looking at the figures again- two 200 amp alternators at 28 volts (when they are running) can produce 11,200 watts.  I just had a custom 12 kw genset made by Dick Wright of Wrico International using the new Kubota D1305 3 cylinder.  It is a longer stroke version of the D1105.  Look at the genset versions that are all rated at 1800rpm.  Then you'll have a nice quiet engine that will last forever.  Just run a 2.5 or 3 to one belt system and the alternators will also be happy.  (6" pulley on the engine and a 2" pulley on the alternator). Good Luck, TomC

[Bob Belter]

Ahoy, Busfolks,

Soundproofing your genset.  I posted this some long time ago, but this piece has so many 'hits', that I thought to repeat:

Sound box, built for my 12 KW genset:
Start with ½" birch plywood, then two layers of 30# roofer's felt, then one layer of 2 lb/sq/ft roofer's lead sheet, then two more layers of felt, and then a layer of 1/2 " plywood.   Sound labyrinths for the air in and out.   Two cheap mufflers in series.
This technique is very effective and very low cost.  Disadvantage is that it is a bit heavier than more elegant schemes.  Not such a big problem on a bus  --  You probably don't want to fly it.   
(My 12kw system is so quiet, that if anyone anywhere around is running their genset, you cannot hear mine).  I had planned to include some internal sound absorbent material, but it was not needed.
BTW, my genset is a belt drive with a 3600 rpm dynamo.  A VW 1600 cc diesel.  Very light weight and compact for 12KW.  I has been a while, and those old VW diesels are now about 'extinct'.  The modern VW  TDI is probably not a good choice today. 
These bus conversions last a long time, and when you use these 'variously derived/adapted' mechanisms, you had better line up your spares (I have). 

Enjoy  /s/  Bob

[Zeroclearance]

Bob are you DC or A/C?   Do you have pictures?

[Bob Belter]

Ahoy, Zero,

No pix --  System is A/C 120v/240v-- Gillette.  A good choice for an A/C dynamo, because they are double wound, and can crank out 80% of their rating on one phase.

Enjoy   /s/   Bob 

[Kenny]

Zero, What's going on with your DC powerplant. How about an update?