Thinking about building a small Diesel DC powerplant

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I have been thinking about making a 400 amp DC powerplant.   There are new surplus Yanmar 2 cylinder 13.4HP engines for a little over $700

Has anyone on the forum built a DC powerplant?

[robertglines1]

I haven't ::)but glad to see someone else thinking outside box what would you power with it?

[luvrbus]

I have never built one but they must work every snowbird in Quartzsite has one from 35 amps up with all different type engines from the knockoff Honda to small diesels


good luck

[chuckd]

Check out www.amplepower.com for their unit to perhaps get some ideas.

Chuck

[Sean]

Kevin,

I have not done this, because I already had a giant 15kW generator that came with the bus.  However, if I was doing a bus from scratch again, I would do a DC generator (and two inverters, to keep AC redundancy).

I don't know what you plan to use for a generator head, but my thought would be an oil-cooled 50DN, with an external oil cooler between the oil pump and the alternator.  These are 6.5kW alternators.  You should be able to run one of these with a 12-bhp motor, geared to drive the alternator around 5,000 rpm.

The single biggest recommendation I can give you is to use a three-stage regulator.  Models are available from Balmar and Ample Power, among others.

Let us know what you decide and how it works out.

-Sean
http://OurOdyssey.BlogSpot.com

[Jerry32]

I too had that idea and have a chinese one syl engine and a 200 amp alt but not together yet. just liike all others it figures to use the inverter for AC and just charge with the gen. Jerry

[JohnEd]

I think Lin had a 50DN for sale.

[Zeroclearance]

Here is a link to the new Yanmar  http://www.surpluscenter.com/item.asp?item=28-1684&catname=engines

Sean I have a spare belt driven 50DN..   I was thinking about picking up 2each 24 volt/200 amp alternators.    I'll keep my larger Powertech genset as a standby unit,  I really don't load it up enough to justify the 20KW.    I hate watching the fuel gauge drop.   

[Kenny]

Sean, Aside from starting the generator, would a battery be involved in your configuration?
Kenny

[Zeroclearance]

Sean, one problem with the 50DN is>>  you need a free oil return.   One would have to mount the alternator higher than the top of the engine oil level.    The oil return must not have any restrictions.   It's similar to the problems we have with turbochargers.   So many folks replace the turbo but don't hot tank or install a new drain tube.   It's filled with sludge and coke.

[Sean]

That's the perfect motor to run the 50DN.  Just the right HP, and you'd only need 1.5:1 on the pulleys.

That would give you 270 amps at ~28 volts.  I'm not sure the 13.5 HP would give you all 400 amps if you tried to run two 200-amp belt drives.  On the plus side, though, you could mount them diametrically opposed around the crank pulley, thus unloading the end bearing.  And I think you can get the 200-amp units as air-cooled models.

-Sean
http://OurOdyssey.BlogSpot.com

[Sean]

Sean, one problem with the 50DN is>>  you need a free oil return.   One would have to mount the alternator higher than the top of the engine oil level.    ...

Very true, so you would need to mount it above the sump and plumb it in somehow, or, alternatively, you can just make a whole separate "cooling system" for the alternator, with its own small sump, electric oil pump, and air-to-oil cooler.

As you know, the free oil return issue also dictates the mounting orientation.

Still, oil cooling tends to perform better than air cooling on these large alternator heads.  FWIW.  And, you already have it...

-Sean
http://OurOdyssey.BlogSpot.com

[Tim Strommen]

This topic has come up before:

http://www.busconversions.com/bbs/index.php?topic=8794.0
http://www.busconversions.com/bbs/index.php?topic=3163.0

If you use an all-electric rig, this may be a solution for you, and even then the idea of a Auxiliary "black start" power plant is interesting (on a 24V rig this can open the possibility of charging and self-jumping the prime-mover).

If you are planning on running a second alternator instead of running a single alternator with two overspeed clutches, and it is intended to charge the same loads as an alternator on the prime mover, remember you will need to modify the regulation a bit.  Balmar has a special device called the "CenterFielder" which does this, but you can make one for peanuts with cube relays yourself too if you have the right circuit.

While you're in there making your own power plant, think about water heating (using the coolant from the genny), and also perhaps charging your chassis air system...  You'll get more bang for your buck for every gallon of fuel you burn that way.

-Tim

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The nice thing about this Yanmar engine is that the torque curve PEAKS at 2400 to 2500 RPM's..   That's where I would size my pulleys to get the desired max alternator sweet spot.   If I could run the engine at 2500 RPM's I would be thrilled to get .5 or .6 gallon burn per hour.   Even with a 50 DN mounted side by side with a belt driven pulley I think that I could run a 2nd 100 amp alternator as a spare..  

The footprint of this power plant woud be small.   Guys have removed the fan to pull less draw from the engine and used remote mounted Honda radiators with 12v auto style fans with temperature control fan switches/relays.   I seen one guy looping the circuit into a Marine water heater first..

The idea is to run make as much "DC" amperage/wattage while not moving down the road with as little fuel burn as possible.

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Tim, for my bus I have 2 Trace 4024's running two seperate battery banks and I'm all electric.   If you look at my avatar my bus is BLACK..   5 Tons of A/C cools the bus.   Right now I have installed a 50DN on my series 60,  this runs with the factory installed Bosch T1 and a factory installed 12V Leece/Neville.

Tim thanks for the links.    With my current systems my 2 battery banks are seperate from my engine/start circuit.