Small 1KW Diesel Generator

[zboss]

Does anyone make a small (around 1 KW) marine diesel generator with an automatic transfer switch? We are intending on using solar using solar but for those cloudy days or weeks the diesel would be programmed to come on when the power in the batteries dips below a certain threshold. I want it tiny because it is only supplementary power and don't want the weight or size of a larger option.

I was looking at the Honda gas generators (EU2000i) but it doesn't look like they can be "permanently" mounted and are not able to support automatic transfer and startup. Please correct me if I am wrong.

[Stumble]

Zboss,

I don't know of a den like this, but if you find one let me know. The problem is that no one makes a Diesel engine this size, so you would have to use gas. To use gas in a permanent installation with an auto-start would raise all sorts of problems with sniffers, blowers, ect. Just to handle the possibility of a fuel vapor leak.

[Cotemar]

This is the only 1kw Suitcase diesel generator I know of and they are not in production yet.

Advanced Propulsion Technologies, Inc.

[Paul L]

Not sure how big your boat is, but once you hit the expense of a diesel generator, I can't see getting one that small. There are fairly small 2.2kw units available. At least these will drive a decent sized charger, heat water, etc. But if you don't have the room, you don't have the room.

[zboss]

The actual size of the space available isn't the problem, its just not wanting to use space or have the weight. I'm fussy like that. At our house we have a 10KW Onan from about 1983 and it's just so large and heavy that it has skewed what I expect from a gen and makes even newer smaller model look bad. So - the smaller and lighter the better.

[GrowleyMonster]

Diesels under 10hp are almost non existent, and for a 1kw generator you would want I am thinking around 3.5hp. I know there are 4-5hp diesels made in China but they are very crude little engines, I am guessing, not particularly efficient or easily maintained. I think they are mostly used for agricultural purposes. I would be surprised if they have refinements like replaceable cylinder sleeves, etc. Homebrewing the controlling system would not be that big of a deal. You would only need single stage charging from the genset, since you would have the smart solar controller for trickle charging etc.

How big is your boat? Is there some reason why you have to go with such a small genset? If it is just to save on initial cost, you might want to keep an eye out for a Lister or Petter single cylinder generator. They are designed to be handcrank started and they are tanks. They run forever. Their drawback is they are dry exhaust, extremely noisy engines, and many if not most of them vibrate a good bit. They were the standard genset for gulf of mexico shrimp trawlers and snapper boats for I guess 50 years, and there are a lot of them just laying up in the weeds in small gulf coast harbors. They are heavy, probably around 300 lbs, and a bit tall for some smaller boat engine spaces, and most have a hand-filled fuel tank on top of the engine. I would not be surprised to see someone giving one away or selling it for a couple hundred bucks since most boats now have 110vAC light plants.

Oops that reminds me, most of those Listers in the weeds have a 36v generator. But that shouldn't be a dealbreaker.

If there is room, you might want to opt for a used Farymann or Bukh or similar small boat propulsion engine, and a big clutch driven alternator.

This discussion definitely brings up the obvious point that there is a possible market in the Western World for a very small diesel engine, both for propulsion and for electrical generation. My boat pushes just fine with a 6hp outboard, and I imagine a 5hp diesel down below would meet my modest needs, and this is a 7600 lb displacement boat. A 20 to 22 foot light displacement sailboat would be well served by a 4hp diesel. But I see most boats today way over-engined. A serious cruiser who sails into harm's way a lot and needs to be able to power into big winds and seas can justify having twice the power needed to achieve hull speed, but for most of us, topping out at just under theoretical hull speed is a good power level, providing decent maneuverability and utility while still being good on the fuel. Now my Atomic, for instance, is rated at 30hp. Actually it probably develops around 20. But top speed of about 6 kt is achieved at just over half throttle. I can get another 600 RPM out of the engine but it won't go a half knot faster. Of course I can simply run the engine at an economical and efficient speed, but there is some operating overhead just swinging the crank, and a smaller engine will have less of this overhead. And in the case of a diesel, you want to RUN the engine, not idle it, anyway.

Now I am thinking that it would be reasonable to think that a 5hp diesel weighing around 150lb could be manufactured and profitably sold at around $4k retail. After all, a Beta13 is 240lb and goes for I think around $6k. A 5hp diesel with a nice big flywheel could be single cylinder. One injector, one pump, one set of valves, one of everything. A twin would be smoother, but with an engine that small, you can afford a nice big flywheel, and a good balancing job should have the vibration at a very tolerable level. Am I far wrong here? And with a mechanical fuel pump and no reliance on glow plugs, it should be hand-crankable. A definite plus for a small engine likely to be use for charging dead batteries. Seems kinda retarded to have a separate battery just to start the engine that charges the rest of the batts, huh?

Volume of manufacture is a major factor in pricing, and one of the reasons that the Beta is so cheap is that the base engine is made in the thousands, as a tractor engine. So our hypothetical 5hp diesel should also be marketed as an industrial or agricultural engine. Small riding mower? small man-portable irrigation pump? emergency home generator or camp generator? RV generator? Gasoline engines in this power range are very light, because of the low compression, but safety and reliability of small gas engines doesn't even compare to a diesel. Give a diesel clean fuel and it will run run run. No ignition system. No carburetor. What's not to like, except for the weight penalty and the price, which would go down as market share increased?

Somebody really needs to build this engine.

[Dockhead]

Originally Posted by GrowleyMonster

Diesels under 10hp are almost non existent, and for a 1kw generator you would want I am thinking around 3.5hp. I know there are 4-5hp diesels made in China but they are very crude little engines, I am guessing, not particularly efficient or easily maintained. I think they are mostly used for agricultural purposes. I would be surprised if they have refinements like replaceable cylinder sleeves, etc. Homebrewing the controlling system would not be that big of a deal. You would only need single stage charging from the genset, since you would have the smart solar controller for trickle charging etc.

How big is your boat? Is there some reason why you have to go with such a small genset? If it is just to save on initial cost, you might want to keep an eye out for a Lister or Petter single cylinder generator. They are designed to be handcrank started and they are tanks. They run forever. Their drawback is they are dry exhaust, extremely noisy engines, and many if not most of them vibrate a good bit. They were the standard genset for gulf of mexico shrimp trawlers and snapper boats for I guess 50 years, and there are a lot of them just laying up in the weeds in small gulf coast harbors. They are heavy, probably around 300 lbs, and a bit tall for some smaller boat engine spaces, and most have a hand-filled fuel tank on top of the engine. I would not be surprised to see someone giving one away or selling it for a couple hundred bucks since most boats now have 110vAC light plants.

Oops that reminds me, most of those Listers in the weeds have a 36v generator. But that shouldn't be a dealbreaker.

If there is room, you might want to opt for a used Farymann or Bukh or similar small boat propulsion engine, and a big clutch driven alternator.

This discussion definitely brings up the obvious point that there is a possible market in the Western World for a very small diesel engine, both for propulsion and for electrical generation. My boat pushes just fine with a 6hp outboard, and I imagine a 5hp diesel down below would meet my modest needs, and this is a 7600 lb displacement boat. A 20 to 22 foot light displacement sailboat would be well served by a 4hp diesel. But I see most boats today way over-engined. A serious cruiser who sails into harm's way a lot and needs to be able to power into big winds and seas can justify having twice the power needed to achieve hull speed, but for most of us, topping out at just under theoretical hull speed is a good power level, providing decent maneuverability and utility while still being good on the fuel. Now my Atomic, for instance, is rated at 30hp. Actually it probably develops around 20. But top speed of about 6 kt is achieved at just over half throttle. I can get another 600 RPM out of the engine but it won't go a half knot faster. Of course I can simply run the engine at an economical and efficient speed, but there is some operating overhead just swinging the crank, and a smaller engine will have less of this overhead. And in the case of a diesel, you want to RUN the engine, not idle it, anyway.

Now I am thinking that it would be reasonable to think that a 5hp diesel weighing around 150lb could be manufactured and profitably sold at around $4k retail. After all, a Beta13 is 240lb and goes for I think around $6k. A 5hp diesel with a nice big flywheel could be single cylinder. One injector, one pump, one set of valves, one of everything. A twin would be smoother, but with an engine that small, you can afford a nice big flywheel, and a good balancing job should have the vibration at a very tolerable level. Am I far wrong here? And with a mechanical fuel pump and no reliance on glow plugs, it should be hand-crankable. A definite plus for a small engine likely to be use for charging dead batteries. Seems kinda retarded to have a separate battery just to start the engine that charges the rest of the batts, huh?

Volume of manufacture is a major factor in pricing, and one of the reasons that the Beta is so cheap is that the base engine is made in the thousands, as a tractor engine. So our hypothetical 5hp diesel should also be marketed as an industrial or agricultural engine. Small riding mower? small man-portable irrigation pump? emergency home generator or camp generator? RV generator? Gasoline engines in this power range are very light, because of the low compression, but safety and reliability of small gas engines doesn't even compare to a diesel. Give a diesel clean fuel and it will run run run. No ignition system. No carburetor. What's not to like, except for the weight penalty and the price, which would go down as market share increased?

Somebody really needs to build this engine.

How about this one? Kubota Engine America - Compact Diesel Engines

Two-cylinder, 479cc displacement, liquid cooled. Weighs only 53 kilos. It develops 13.3 horsepower at 3600 RPM -- sensibly derated to 1500 rpm or so, I guess that would be 6 horsepower or so.

There's also this one:

There's also this: Kubota Engine America - Compact Diesel Engines, a one-cylinder liquid cooled engine. 6hp at 3600 RPM and weighs only 38 kilos. 276cc. I guess derated it would make 3 or 4 horsepower at a reasonable RPM.

But I would go for the two-cylinder liquid cooled one for small power. It would make about 3.5kW of electrical power, I guess, which surely is a handy size, allowing you to charge batts intensively when you need to.

For really small power, I think I might like something like the sadly now defunct Whispergen Stirling engine generator. This produces heat as well, and is much quieter than any diesel engine can be, so you can run it continuously or most of the time.

Otherwise, there's the 4.5kW generator from Northern Lights, the Rolls Royce of generator makers. Three cylinders, 1500 rpm. If you have room, this is surely a great solution. This is small enough not to be bothered by a 1kW load, and will be really quiet and smooth, with three cylinders and only 760cc of displacement.

[zboss]

Originally Posted by Dockhead

How about this one? Kubota Engine America - Compact Diesel Engines

That kubota is just about perfect. I didn't realize they made one that size.

Thanks!

[Paul L]

Pretty close to the Kubota that is used in this Phasor genset
Phasor Marine Generators LP1-3.5KW

[deckofficer]

If you don't need a hot shower from it running and want light weight DC charging and air cooled simplicity try this Generator, 1-2.2 kW Lombardini LD15-315

A DC output gen set is much lighter than AC and can run at any rpm instead of a 60 hz dictated 1800 or 3600. If you run off an inverter for your AC loads, then make things easy and just charge the battery and save 100+ lbs.

[GrowleyMonster]

Originally Posted by Dockhead

How about this one? Kubota Engine America - Compact Diesel Engines

Two-cylinder, 479cc displacement, liquid cooled. Weighs only 53 kilos. It develops 13.3 horsepower at 3600 RPM -- sensibly derated to 1500 rpm or so, I guess that would be 6 horsepower or so.

There's also this one:

There's also this: Kubota Engine America - Compact Diesel Engines, a one-cylinder liquid cooled engine. 6hp at 3600 RPM and weighs only 38 kilos. 276cc. I guess derated it would make 3 or 4 horsepower at a reasonable RPM.

But I would go for the two-cylinder liquid cooled one for small power. It would make about 3.5kW of electrical power, I guess, which surely is a handy size, allowing you to charge batts intensively when you need to.

For really small power, I think I might like something like the sadly now defunct Whispergen Stirling engine generator. This produces heat as well, and is much quieter than any diesel engine can be, so you can run it continuously or most of the time.

Otherwise, there's the 4.5kW generator from Northern Lights, the Rolls Royce of generator makers. Three cylinders, 1500 rpm. If you have room, this is surely a great solution. This is small enough not to be bothered by a 1kW load, and will be really quiet and smooth, with three cylinders and only 760cc of displacement.

Well that gives one something to think about. Figure about a grand for a transmission, though. I assume those are bobtail engines with no clutch or anything on them. And $300 or so to lash up a freshwater cooling system. I bet the single cylinder Kubota Engine America - Compact Diesel Engines is well under $3k and I think this is the link you meant to post for the 38kg engine. The dimensions are intriguing. Could make a dinghy motor! It would work for a portable generator I'm thinking. A frame could be bolted or welded together from angle iron, a generator or alternator belt driven and for DC, no electronic governor would be needed.

[GrowleyMonster]

Originally Posted by Cotemar

This is the only 1kw Suitcase diesel generator I know of and they are not in production yet.

Advanced Propulsion Technologies, Inc.

KEWL! But I bet it is noisy as hell. And two stroke? On regular #2 street diesel? There might be wear issues unless the fuel is mixed with some sort of two stroke oil. And the compression must be pretty low so probably will need glowplug starting. Still pretty cool, though. What next... a lunchbox sized collapsible diesel outboard?

I think that engine would work in an ultralight plane or something. Or a diesel moped.

I am liking that concept a bit. I will be keeping an eye on those guys. I like to see people pushing the envelope.

[nhschneider]

When we bought our boat, it had a Westerbeke 6.5kw genset installed and even though it didn't have all that many hours on it, it was very trouble prone. In 2009, we replaced the Westerbeke with an AquaMarine MyT-Gen, which is a 150-amp 12v alternator mounted on a Kubota single-cylinder diesel. Since we're 100% 12 volts (refrigeration, watermaker, etc) this made a lot of sense for us. Believe it or not, I think the genset took more man-hours to install than the propulsion engine but that's for another post.

We have over 1,000 hours on the AquaMarine genset now and other than replacing a water pump">raw water pump (AquaMarine standard configuration uses an electric raw water pump - in hind sight, I would have had it equipped with a rubber impeller, belt-driven pump), the genset has been excellent, if very noisy. It uses about a liter-and-a-half of fuel per hour and zero lubricating oil between changes.

Fair winds and calm seas.

[FlyingCloud1937]

Originally Posted by zboss

Does anyone make a small (around 1 KW) marine diesel generator with an automatic transfer switch? We are intending on using solar using solar but for those cloudy days or weeks the diesel would be programmed to come on when the power in the batteries dips below a certain threshold. I want it tiny because it is only supplementary power and don't want the weight or size of a larger option.

I was looking at the Honda gas generators (EU2000i) but it doesn't look like they can be "permanently" mounted and are not able to support automatic transfer and startup. Please correct me if I am wrong.

How about something like this

perky/cat/volvo



It weighs in at 170lbs, 21" tall X 14' wide X16" deep, makes 3.8kw DC, it heats domestic hot water as a byproduct.

It's quiet.

I have now finished my variable speed ECU. It's auto start/stop/manual. Has a 3 step charge regulator, that can be configured to charge Li-Ion bats.

You want air.con/water maker/ac50/60hz/dive compressor? no problems.

State of the art Variable Speed Control for my dc gen.

This is how the system works start the gen and the controller holds it at 1000 rpm for 60 seconds to allow oil up. Then it slope up the rpm to 1600 and sends a signal to the Balmar regulator to turn on, as well as to a time delay relay, the puts the Balmar controller in small engine mode. Then it ramps up speed to 2000 rpm and holds for 45 seconds, the Balmar starts ramp up of the field to the alternator set to 60 seconds this allows the engine speed to stay ahead of the alternator out put. At the end of the 45 seconds the governor begins to ramp up to full speed of 2800 rpm or at a speed to be determined by the controller between 1600 rpm and 2800 rpm depending on the current out put/hp required by the alternator.

The speed is measured by a tooth counting flywheel sensor.

So now when the engine is running, the speed will follow the alternator current out put up and down between 1600 and 2800 rpm. If a large load is applied to the bat bank by the inverter then a separate Hall effects sensors will alert the controller to again ramp up speed.

I worked with the engineer at PG to tweak the software based on needs. It also has 3 adjustable pots on-board to fine tune, as well as an RS 232 port to tweak the software after installation with a laptop.

I worked out a spreadsheet to follow the hp required by the alternator, to match the hp output of the diesel.

An add on belt drive ac gen is accommodated by a switch that holds the diesel at 2200 rpm, and puts the dc alternator in small engine mode as a current limiter.

Next month the second unit goes to Caterpillar for Certification... then to test market. The unit in the picture is my test-bed.

Lloyd

[Teknav]

Diesel powered engine and light weight are mutually exclusive. There is no such a thing as a light weight diesel engine; engineering wise, not yet invented. Mauritz