WHAT IS A GOOD GENERATOR ??

[DMCantor]

You might consider the small Fischer Panda DC generator. I know that F-P has a terrible reputation, but that is for the AC generators that run at 3600 rpm. The DC unit is very small, fuel efficient, and runs at only ca. 2200 rpm. That lower speed is much quieter, and is MUCH easier on the engine. As I recall, you get about 150 amps of charging current.

There are many high-quality 3-stage alternator controllers to manage the battery charging. We have a Balmar, and it works perfectly.

[Greg Mason]

Always an interesting topic, when it comes to needs. When I searched out a new boat, I soon discovered that a lot of power boats had electric stoves. I asked about this, and the consensus was that power boaters are afraid of propane and sailors love it. Same with a gen set. If you are diesel powered, so will your gen set, gas = gas. I have a 3 cylinder Yanmar as a power source for my Kohler, sound proofed, runs at a consistent speed, and charges all batteries and any 120v needs. I do have a propane stove and oven. The diesel mechanics will tell you low speed operation for diesels is not the best option, that a constant rpm works best for long term service. The most common service engine ever, for gen sets, tractors, boats etc is the Perkins 4108, a standard for performance. But, what works for each person is the right thing of course, so there really is no right gen set for all, as we have different needs and limitations.

[a64pilot]

Originally Posted by Dockhead

Sounds very good!

Is it reliable? Have you had any trouble with yours?

Most trouble I have had was self induced. It comes with and I used the tiny spin on Racor like I have for my outboard.
Well I guess I have dirty fuel as filtering to 2 micron with that tiny filter had it clogging pretty quick, plus the cartridges were harder to find and more expensive than ones for a Racor 500. I ended up plumbing after my main engine filters and using a Racor 500 for the gen with a 2micron cartridge, first filtering down to 30 with the big motors filters and maybe the 500 having so much filter area I have not had to change a filter since then.
The little Kubota has a lot of return fuel, many more times the fuel it burns, so while it may only burn a quart an hour, it’s filtering 10 gls an hour or so, it’s in effect a fuel polisher.
The early models had exhaust elbow problems with the SS exhaust elbow rusting out early and letting water into the engine usually seizing the exhaust valve, but never heard of any catastrophic damage, just stuck exhaust valves.
New models have a different elbow design with a short insulated dry section and inject the water downstream so it cannot get back up into the engine.
Also the early models had dirty power if ordered without an AVR, apparently there was an AVR model available. Both the 3.5 and 5.5 use the same gen head, the 3.5 is engine power limited, not generator limited, the gen head is I think a 6 KW Syncro, Spanish company I think. I have no dirty power issues, everything runs fine, but I have not put it on a scope either. I believe inverters didn’t like the dirty power of the old models.
Nex Gen is located in Jacksonville Fl. They have always answered any calls I have made to them.

The one major problem I had that really upset me was the Raw water pump started leaking and spraying the entire generator down with salt water, it continued to do this until the pump finally seized, the belt jumped off and the generator overheated and shut down causing me of course to look inside.
A raw water pump inside of a generator enclosure is I believe a bad design, and I think they all have it. I removed the pump entirely and instead use a March 110VAC airconditioner water pump. First they are extremely reliable, run for years and no telling how many thousand hours between failure, and do not pump water if the generator is not making electricity so you cannot flood the engine from overcranking if it doesn’t start, and of course no impeller to worry about, and it’s not in the enclosure, they will not self prime, they have to be below waterline.
I can see a mechanical water pump on an engine that varies RPM as maybe you want more water flow at high RPM, but an AC generator is running or it’s not, an impeller water pump is just a maintenance headache you don’t need.

I can see how on a boat like yours that you don’t want Solar etc., that a 3.5KW Nex Gen could be a good inexpensive, light weight back up, can’t run everything maybe, but with 3000W or so you can do a lot of battery charging. It will make 3500W, but I’m hesitant to keep it there continuously, it will do it, but you can tell it’s working hard, real hard.

Typical fuel consumption is four hours on a US gallon of Diesel. Oil change interval is 100 hours.

I initially had two Honda’s that I connected together, they took up just as much room and were not all that much lighter than the NexGen, and of course you have gasoline vapors with them too.
I see the little Nexgen as the next step beyond Honda’s, not a continuous generator that runs 24 / 7 although if you call Nexgen he will tell you that they have many in Commercial boats that do just that and do fine.
I think one of the big heavy 1800 RPM multi cylinder sets are better suited for that.

[travellerw]

Originally Posted by a64pilot

Most trouble I have had was self induced. It comes with and I used the tiny spin on Racor like I have for my outboard.
Well I guess I have dirty fuel as filtering to 2 micron with that tiny filter had it clogging pretty quick, plus the cartridges were harder to find and more expensive than ones for a Racor 500. I ended up plumbing after my main engine filters and using a Racor 500 for the gen with a 2micron cartridge, first filtering down to 30 with the big motors filters and maybe the 500 having so much filter area I have not had to change a filter since then.
The little Kubota has a lot of return fuel, many more times the fuel it burns, so while it may only burn a quart an hour, it’s filtering 10 gls an hour or so, it’s in effect a fuel polisher.
The early models had exhaust elbow problems with the SS exhaust elbow rusting out early and letting water into the engine usually seizing the exhaust valve, but never heard of any catastrophic damage, just stuck exhaust valves.
New models have a different elbow design with a short insulated dry section and inject the water downstream so it cannot get back up into the engine.
Also the early models had dirty power if ordered without an AVR, apparently there was an AVR model available. Both the 3.5 and 5.5 use the same gen head, the 3.5 is engine power limited, not generator limited, the gen head is I think a 6 KW Syncro, Spanish company I think. I have no dirty power issues, everything runs fine, but I have not put it on a scope either. I believe inverters didn’t like the dirty power of the old models.
Nex Gen is located in Jacksonville Fl. They have always answered any calls I have made to them.

The one major problem I had that really upset me was the Raw water pump started leaking and spraying the entire generator down with salt water, it continued to do this until the pump finally seized, the belt jumped off and the generator overheated and shut down causing me of course to look inside.
A raw water pump inside of a generator enclosure is I believe a bad design, and I think they all have it. I removed the pump entirely and instead use a March 110VAC airconditioner water pump. First they are extremely reliable, run for years and no telling how many thousand hours between failure, and do not pump water if the generator is not making electricity so you cannot flood the engine from overcranking if it doesn’t start, and of course no impeller to worry about, and it’s not in the enclosure, they will not self prime, they have to be below waterline.
I can see a mechanical water pump on an engine that varies RPM as maybe you want more water flow at high RPM, but an AC generator is running or it’s not, an impeller water pump is just a maintenance headache you don’t need.

I can see how on a boat like yours that you don’t want Solar etc., that a 3.5KW Nex Gen could be a good inexpensive, light weight back up, can’t run everything maybe, but with 3000W or so you can do a lot of battery charging. It will make 3500W, but I’m hesitant to keep it there continuously, it will do it, but you can tell it’s working hard, real hard.

Typical fuel consumption is four hours on a US gallon of Diesel. Oil change interval is 100 hours.

I initially had two Honda’s that I connected together, they took up just as much room and were not all that much lighter than the NexGen, and of course you have gasoline vapors with them too.
I see the little Nexgen as the next step beyond Honda’s, not a continuous generator that runs 24 / 7 although if you call Nexgen he will tell you that they have many in Commercial boats that do just that and do fine.
I think one of the big heavy 1800 RPM multi cylinder sets are better suited for that.

Could you give us a rough idea of cost.. I couldn't find it on thier webpage.

[newhaul]

How about polar power . They are based on volvo diesel engines
https://polarpower.com/marine-dc-generators/#tab-id-1
Here's the per for the 3-5kw unit
https://www.polarpower.com/wp-conten...-rev-6-web.pdf
No experience just googled it.

[noelex 77]

Originally Posted by Dockhead

Noelex had something like this on his old boat, using a small propulsion engine (IIRC) to drive a jumbo school bus alternator.

It worked well although we prefer the reliability and silence of solar power so once the solar was installed it was used very little.

The advantages of a DC generator is that it is not limited to a set speed and the components are simpler and less proprietary than an AC unit. It was a 15Hp Nanni diesel engine, coupled to a large frame alternator and originally a watermaker high pressure pump.

[redsky49]

Particularly for North Americans, US based Westerbeke has long offered a range of low speed (1800 rpm) diesel generators, in addition to, I believe, gasoline generators.

[warrior 90]

In general the most reliable system aboard is solar with a sufficient sized battery bank and corresponding inverter for AC consumers. Ad on the alternator from the engine and additional wind gen and other DC sources
I see no sense in adding an AC source for charging on board as this only creates extra risk of failure. To keep things simple I would always prefere a diesel DC generator. Lower maintanace, same fuel system and no explosive gas fumes and most likely less weight.
With the battery bank I have a stable and high quality energy and I only need efficient DC charging,

But before I get into any considerations about a generator I would study the options I get with a Victron Combi charger inverter Models Multi Plus with "POWER ASSIST" function
https://www.victronenergy.com/upload...ine_EN_web.pdf

With "POWER ASSIST" it is no longer necessary to size a generator on the maximum peak load. Use the most efficient size generator instead.

That translates into less weight, less size, less $$$$

[john61ct]

Originally Posted by Dockhead

there isn't any such thing as a "specialized marine alternator"

Balmar, much more expensive than stock Leece Neville or ​Delco-Remy, not sure if more to them than salt-spray proofing

Originally Posted by Dockhead

how to operate it. Maybe you just increase the revs if you think you will need more power -- you can work out max available power at different revs. Being careful not to leave it running at higher speeds with no load on. Or maybe it would be possible to invent some control system which would drop the revs automatically.

No, you set the pulley ratio so 70-80% of rated amps is produced at low constant rpm, long as enough torque is there when alt(s) get loaded down.

A VR like Balmar's MC-612, Ample Power, Sterling helps regulate the charge profile.

Yes could be attached to the propulsion engine if there's room. I was thinking dedicated in place of a traditional genset.

[john61ct]

Originally Posted by a64pilot

An issue with having a pure DC generator is how good a battery charger will it be?

Function of the VR. Balmar's MC-612 is excellent, fully adjustable setpoints so suitable for LFP.

Originally Posted by a64pilot

However the biggest problem with a pure DC genset in my opinion is their relative non availability. In truth I have never seen one.
As much as I like Science projects I have decided to as much as possible to buy off the shelf

Exactly my grievance, started off with "I wish".

But as I said not a huge challenge with the right assistance, real key is identifying the right engine.

[svninkasi]

Hands down phasor!!

[Paramotorgreg]

We have an HFL Mariner 6KVa AC generator. HFL are a German company and they have used a Mitsubishi Diesel engine which they have adapted for marine use. It's now almost 20 years old and I have no complaints; quiet, efficient, reliable, easily serviced - recommended.

[Mikado]

Originally Posted by geoleo

One that has a heat exchanger and 12volt output as well as 120 volt AC ??? Approximately 4-6 KW---- Don't say MASE!

Not sure what your prime mover engine is, gas or diesel, but fuel choice should be your first decision.

Why would you would limit your choices looking for AC/DC output with reliable, inexpensive AC/DC inverters available.

I have a Westerbeke 7.6 BTD 3 cyl diesel. Low RPM, quiet with low fuel usage.

Very pleased with my choice.

[Fast Tack]

That is a great point about eliminating a potential problem by having an AC Air Conditioning Water Pump. Off hand do you know what size or model of the March water pump your using ?

[Captain Bill]

Originally Posted by svninkasi

Hands down phasor!!

Why ?