High RPM Diesel Gensets

Gentlemen

I would like to know your opinions on high RPM gensets ( Fisher Panda for example)
Are they long lasting equipment? Are they reliable?
Let it all out, don't hold it back.

Thanks

Portuguese

On my previous boat I had a 3600 rpm Kholer genset, I believe it had a 1 cyl Farymann engine. It performed and ran fine although I didn't put a lot of hours on it about 400 if I remember correctly. I find it vibrated much more than my current 1800 rpm Onan 9kw, 3 cyl Kubota engine, and the high rpms made it sound like it was about to "blow up".
When I bought it to put in the Camano 31 I owned then I looked at the Panda, at that time it had lots of negative reviews on the internet boating sites I used. Maybe different now.
Good luck
Steve W

Portuguese said:

Gentlemen

I would like to know your opinions on high RPM gensets ( Fisher Panda for example)
Are they long lasting equipment? Are they reliable?
Let it all out, don't hold it back.

Thanks

Portuguese

Click to expand...

You will not get the lifespan out of a 3600 RPM generator that you get out of a 1800 RPM set.

Thay may not mean much in a recreational marine enviroment though, since we don't put the hours on a generator to wear out either one.

What I'd look for is ease of maintenance. Some of the little Fischer Panda units are cute, but can you work on them easily in place?

What you gain in less weight and a smaller footprint might equate to a unit that is so compact that it makes it difficult to service.

Will you require 120 or 240 volt AC power? What power output will you require? Nextgen has a compact 5 1/2 KW Kubota powered gen that turns at 2800 rpm. It uses a cog belt to drive the gen that is like a timing belt on a car. It is a pretty smooth unit. Service points are on the front.

NEXT GENERATION POWER ENGINEERING INC.

For lots of genset use and a desire for efficiency and some quiet , I think a DC unit with a good sine wave inverter is the most practical and versatile .

A DC noisemaker can run at just enough RPM to power the current loading , idle works if the load is low.

220A 12v unit is common as are 300A 24V units in many buses.

I would roll my own if I had to operate with house current for much time.

A big Trace will put out 4000W on 24V , as will other brands.

For infrequent use and smaller loading the Honda 2KW gas unit seems the choice of many cruisers.

I second the NexGen line of 2,800 rpm gensets. Even the 3.5 KW unit is big enough to start a 16,000 BTU unit if no other significant loads are connected at the time. And it is reasonably smooth and quiet.

The Fischer Panda is a "wonderful piece of German over engineering that doesn't work in the real world" to quote one detractor on boatdiesel.

There are other high rpm gensets, the Phasor and Entec West, and there may be others.

David

I had a Kohler powered by a 3600 rpm Lister-Petter diesel as oem on my old Mainship.
Even with a sound enclosure it always sounded like I had a lawnmower running in the bilge. Sounded like that outside the boat as well.

There...I let it out.

That was late 70's technology, hopefully today the noise level is lower.

Over the last 17 years I have had 3 gen sets on Tidahapah.
2 x 3000 RPM 240 V 50 Hz
and the last one a 1500 RPM 240 V 50 HZ unit.
The 1 st 3000 RPM er I wore out in 3 years. Rebuilt it but did not reinstall it instead made the drastic mistake of buying another 3000 RPM er, (Kubota engine) wore it out over the next 5 years.
Have since installed a 3 cyl Perkins driven Stamford 9 KVA gen set that now has 4000 hrs on it and going strong. Just recently did a cyl head O'haul just because I had some down time.
Would not ever consider a high reving gen set again.
Really like the MASE gen sets, very quiet and well built with Yanmar engines.
One of these would be my next choice if required.

So the question is what do you want to use the gen set for and is it temporary?

If you are going to install hydraulic get home/bow thruster on the boat, I would size the gen set based on the HP of the engine and the RPM required by the hydraulic pump/system. The larger HP/KW gen sets run 1500 to 1800 rpm which most generators require to out put 50/60 htz and the volts.

In the past we also discussed cruise generator powered by the main engine. We have three, a small portable diesel, the main Kohler 10 KW that powers the hydrualic bow thruster/get home, and 5 kw cruise gen set when we are out and about to save fuel and noise. If the main Kolher needs replacing it will be the biggest HP gen set that can fit the space as the KW is not that important.

This decision should be driven primarily by considering first your electrical needs. If you are not intending AC-powered air-con (or are happy to only use this when on shorepower), then I am with FF at post #5: get a DC genset of 100-200A output and a quality inverter/charger. If you plan air-con and you want to be able to run it at anchor, often, then 1500 (50hz) or 1800 (60hz) diesel gensets are generally preferred for noise and longevity over high-rpm gensets. But if your air-con use at anchor is modest/occassional and you have good alternators and a quality inverter/charger, the high-rpm gensets can be a very cost-effective approach. MasterVolt & Victron (& perhaps others?) make inverter/chargers that can be parallel'd with gensets. This allows for a significant down-sizing of the genset, as the momentary power surges associated with starting motor loads (as experienced with air-con) can be handled by the inverter supplementing the genset and the genset itself can be sized to just cope with the more typical running loads. In my own case, this allowed down-sizing from a 13kva to a 7.5kva genset...big difference in cost, weight, noise, etc.

I've been thinking of starting a new thread asking for comments on the Next Generator but maybe a reply to this thread will help me and the original poster. I've been looking at the 3.5 KW Next generator for doing just 2 functions - heat water and charge the battery bank. Nothing else. I've looked at all the small generators - Next, Entec, Fisher Panda, Mase and Phasor (which seems like a knock off of the Next generator) and I have come to the conclusion that the Next generator would best meet my requirements because of its weight and size. It also appears to have the best pricing compared to its competitors. Although I would prefer a 1800 RPM generator, they are too big and heavy for my boat. The Next generator is 200 lbs with sound shield and is the lightest of them all and it runs at 2800 RPM rather than 3600 RPM of the others.

So, does anyone have any direct experience with the Next generator and can comment on noise, vibration and reliability?

Thanks,
Ron

Phil and ALL:

I put this thread in because the high RPM gensets are getting cheaper in Brazil. However, I do prefer a low RPM MASE or ONAN or any other running @ 1800 RPM. In addition to that, I intend to connect a 8 KVA 120 v alternator to the main engine as I will cruise between 1800 and 2000 RPM. This will give me good cool air condition in the country of the never ending summer. When I go south, Argentina, Uruguay or South Brazil, I will put the AC units on heat mode, while I cruise @ 6 - 7 knots. My maximum constant needs are 46 AMPS 6 KVA, with a 8 KVA genset I'll be set, I think!

Phil

I ended up geting an electrical BT

Portuguese: sounds like you are going in the right direction with the cruise generator. I'd recommend the best inverter/charger you can find with parallel operation capability and as you are going to be using a genset a lot, an appropriately-sized (given the inverter/charger) 1800rpm genset for low noise, longevity and efficiency.

windmist said:

I've been thinking of starting a new thread asking for comments on the Next Generator but maybe a reply to this thread will help me and the original poster. I've been looking at the 3.5 KW Next generator for doing just 2 functions - heat water and charge the battery bank. Nothing else. I've looked at all the small generators - Next, Entec, Fisher Panda, Mase and Phasor (which seems like a knock off of the Next generator) and I have come to the conclusion that the Next generator would best meet my requirements because of its weight and size. It also appears to have the best pricing compared to its competitors. Although I would prefer a 1800 RPM generator, they are too big and heavy for my boat. The Next generator is 200 lbs with sound shield and is the lightest of them all and it runs at 2800 RPM rather than 3600 RPM of the others.

So, does anyone have any direct experience with the Next generator and can comment on noise, vibration and reliability?

Thanks,
Ron

Click to expand...

Ron, I had a Nextgen 5.5 kw in my 34' Mainship Pilot. It had a 12,000 btu A/C in the cabin and a 16,000 on the helm deck. It would run everything. I would recommend that size as you never know what you will add later. I had one problem with it. Just a small bearing. I was in St. Augustine so ran up to their assembly place in Jacksonville. They were very helpful, and didn't charge for the part. I was very happy with the unit.

Portuguese,
Mate you are on the right track.
Down here in Australia , similar wether conditions and also you may want to run a water maker.
I have a 9 KVA 1500 RPM gen set as main. A cruise gen 5 KVA driven off the front of my main engine, especially handy for long trips.A 3000 Watt , 70 amp, 24 V Victron inverter charger for daily use on the hook and a couple of solar panels
The back up is a 2 KVA Honda petrol gen set that has come in handy , especially if only want to top up the batteries on a cloudy day and also go out fishing in the tender.

Ron,
I installed a NextGen 5.5 kw in my boat earlier this year. I chose it for several reasons, it is lightweight, it fits perfectly in a space in my engine room, it is an easy to maintain design and has simple controls.

The guys that build it are easy to contact and are very willing to answer questions. I don't have enough hours on it yet to comment on durability. With the sound shield, it doesn't make enough noise to be annoying inside the boat. I think the exhaust makes enough noise to irritate your neighbors if run constantly.
Lyle

I'd be very curious to see the real sound level differences between say the next gen unit and a northern lights.

People say they're louder but are they really ? You never know.

ksanders said:

I'd be very curious to see the real sound level differences between say the next gen unit and a northern lights.

People say they're louder but are they really ? You never know.

Click to expand...

I had a 5.5 kw Nextgen, and now have a 12 kw Northern Lights. Not that much difference in noise.

Portuguese said:

Phil

I ended up geting an electrical BT

Click to expand...

Electric works! Any plan for a get home?

So you are going to have a 120 volt cruise alternator/gen. Might want to think about using an electric clutch so it free wheels when not using and/or starting the engine. Both the cruise gen and the hydrailic pump have electric clutch. I have change the pulley on the both the Perkins gen motor and DD 671 to bigger diameter to get the max performance at a lower RPM.

Since you have plans to charter and cruise with the boat then make sure what you install meets the needs in the short term and long term. The Eagle was built to be a long range coastal cruising, but even thou we use her as a dock condo, we maintain and upgrade keep in mind what she was originally built for long range crusing.

Thanks Moonstruck and Norwester for your comments on the Nextgen generator. I think this is the way I will go if I even do it.

Ron

I'm in the process of moving our house batteries and reinforcing the shelf for the instal of a Next Gen 3.5. We should have it up and running soon. I have been researching small generators for the last two years and finally settled on the Next Gen based on owners feedback, the compact size and weight. We also chose the sound shield. Once the unit is installed we'll post it on our Beach House blog. Chuck

Tidahapah said:

Over the last 17 years I have had 3 gen sets on Tidahapah.
2 x 3000 RPM 240 V 50 Hz
and the last one a 1500 RPM 240 V 50 HZ unit.
The 1 st 3000 RPM er I wore out in 3 years. Rebuilt it but did not reinstall it instead made the drastic mistake of buying another 3000 RPM er, (Kubota engine) wore it out over the next 5 years.
Have since installed a 3 cyl Perkins driven Stamford 9 KVA gen set that now has 4000 hrs on it and going strong. Just recently did a cyl head O'haul just because I had some down time.
Would not ever consider a high reving gen set again.
Really like the MASE gen sets, very quiet and well built with Yanmar engines.
One of these would be my next choice if required.

Click to expand...

I'll bet the high speed gen set engines died from excessive under loading .. Not from high engine speeds. This is the only application where underloading can be a real probable threat. Each power stroke requires less force w higher rpm or more cylinders. An engine run properly should last long enough so it would be impossible to wear it out no mater what rpm the engine operates at. If one could run an engine 15000 to 20000 hrs a lower speed engine may or probably would outlast a slower turning unit but pleasure boats just don't accumulate enough time to wear out properly run engines whether as a prime mover or as a gen set. A high speed engine may SOUND like it's over stressed but if one considers the forces on the parts of the engine like piston speed and BMEPa smaller engine turning faster may be dealing w less stress. I had a Nissan diesel car once that sounded terrible at low engine speeds and got very noticeably quieter w considerably more throttle (load) .. a big difference actually. So much of the time what an engine sounds like may be very different from how "happy" it is or how much wear is taking place.
So the idea that an engine turning faster will wear out quickly is in general just plain bunk. Obviously ther'e will be exceptions and taken to extremes what I'm saying is just plain bunk. Huge very slow engines last much longer than small high speed units but within the realm of what we use in trawlers almost no engine will accumulate enough hours to wear out so this question is of little or no interest to trawlermen.

I agree with ManyBoats at post #23 in principle. One often reported issue is that high rpm engines of the type mated to small gensets are not as well built, so ManyBoats is right that rpm is not itself a source of shorter life but poorer build quality certainly is.

Also: what about noise? Are hi rpm units inherently noisier than 1800rpm gensets?

Aquabelle said:

I agree with ManyBoats at post #23 in principle. One often reported issue is that high rpm engines of the type mated to small gensets are not as well built, so ManyBoats is right that rpm is not itself a source of shorter life but poorer build quality certainly is.

Also: what about noise? Are hi rpm units inherently noisier than 1800rpm gensets?

Click to expand...

I don't really know but I think load is more a generator of noise than rpm. And design features like composition chamber shape and valve gear design effect noise. As per the Nissan diesel auto engine engine noise can actually reduce w more load. So there are many variables. Much of the time vibration causes most of the noise in a boat and lower rpm or fewer cylinders will increase vibration at the same power output. But re the OP I think engine rpm in both propulsion and gen set engines is completely a non issue.

manyboats said:

So the idea that an engine turning faster will wear out quickly is in general just plain bunk.

Click to expand...

You're incorrect about that. Not bunk just incorrect. I have direct hands on experience in this area

A industrial quality 1800 RPM diesel generator engine will generally go something between 20 and 30,000 hours, if it is run at a reasonable loading rate, and otherwise maintained properly.

A industrial quality 3600 RPM generator set might go 5,000 hours but thats honestly pretty few and far between.

I see it with my own eyes. Take a yanmar small diesel and spin it 3600 rpm in a light tower, its a 5,000 hour engine at best. Take that same basic engine and spin it at 1800 RPM and its a 20,000 hour engine conservativly.

That said I would argue in a recreational marine application its for the most part irrelevant. Most recreational generators are infrequently used, and run with almost zero preventative maintenance except oil changes. couple that with a corrosive enviroment and you are setting the engine up for a premature failure.

You really want to see an engine last, look into the generators in the oil field. We have units that typically go 7-10 years of continous duty running with the only shut down for maintenance. Why do these units last so long? They turn at 1200 RPM. Some units that pump oil turn at 600 RPM and can last a lot longer than that. Years longer.

Engine life is very much related to engine speed, but in a marine enviroment where few engines actually wear out having died before their time due to a catastrophic failure, does it really matter?

"Engine life is very much related to engine speed, but in a marine enviroment where few engines actually wear out having died before their time due to a catastrophic failure, does it really matter?"


What does matter more is fuel consumption.
A few folks I have talked to that removed antique OHNO or Koller diesel units found the fuel consumption WENT UP when the new units were operated as usual on small boats , at light loading.

Some were normally left on a few hours after meal service to run the reefer and charge the batts .
They found the fuel consumption at these minor loads to be about double their removed antiques fuel burn.

At my current usage, it looks like I'll need to replace the little Yanmar in the Mase Generator in 2028. More to worry about

Capn Chuck said:

I'm in the process of moving our house batteries and reinforcing the shelf for the instal of a Next Gen 3.5. We should have it up and running soon. I have been researching small generators for the last two years and finally settled on the Next Gen based on owners feedback, the compact size and weight. We also chose the sound shield. Once the unit is installed we'll post it on our Beach House blog. Chuck

Click to expand...

Moving the batteries to make room for a genset is a great idea, Chuck. What expectation do you have for the number of hours you'll get out of the genset?

Kasanders,
OK, I'll buy that but I may be confusing "high rpm" for medium speed like the 3000rpm engine in my boat w lighter weight 3600rpm units. My propulshion engine would run at 1800rpm as a gen eng. I really don't have any experience w higher speed engines except a 3400rpm Yanmar. Those Yanmars seem to last in the little Albin's but then again nobody runs them enough hours to kill them.
So I'll take back what I said about the little gen sets but I don't see a higher rpm Volvo or Yanmar propulsion engine as having a short life as a result of it's higher rpm running. But perhaps I'm wrong about that too. But that should be another thread if it should be discussed at all.