Quietest Diesel Gen set?

[a64pilot]

In the smallish size range say 4 to 6 KW, 115V 60Hz, which one is quietest? I heard here and believe it's correct that noise is 80% structural and 20% accoustic. Makes sense to me, so I guess what I'm asking is which Gen is perceived to be quietest, good isolation from the hull would be important as well as exhaust noise?

[colemj]

The slowest running one will be the quietest. After that it goes by number of cylinders, with 1 being noisy. Most of them come with sound enclosures and isolation mounts that do a very good job at keeping noise low enough that they are barely audible.

Mark

[a64pilot]

60Hz gen sets I assume will run either at 1800 RPM or 3600 RPM, I had thought all decent gen sets would be 1800 RPM? Of course if there are inverter type like the little Honda's, then RPM could be variable, load dependant, but that's not done in larger gen sets, is it?
My experience is with older Westerbekes and RV gen sets, but don't know what's available now, I had never seen a Fisher / Panda until I started boat shopping for example, but you don't get to hear them run when your just looking

[colemj]

There are many gensets running higher than 1800rpm. It doesn't have to be 3600 - several are belt-driven and use pulley ratios to keep the generator at 3600rpm. For example, NextGen runs at 2800rpm.

Some of the Fisher/Pandas are inverter types. They always have them running at boat shows if you can make one.

Mark

[Cotemar]

Fisher / Panda generators at the boat shows in the enclosures are very quiet.

Northern Lights are the generator that gets very high marks, but they are very heavy.

[a64pilot]

OK, hadn't thought about the generator being at a different RPM than the engine, I had assumed direct drive, but short of going to a boat show, no recommendations on gen sets in the 4 to 6 KW range? How about adding ease of service, reliability and longevity and availability of parts to the matrix? Price is relevant, but not as relevant as quality

[colemj]

Ah, that is a different question than your original post!

If weight and size is no problem, I would go Northern Lights. If weight and size is a problem, I would go NextGen. I wouldn't go Fisher/Panda regardless.

But that is just me.

Mark

[Sailmonkey]

What is your intended use for a gen? That will help out with size and best in the size range.
Fwiw the Panda generators gave me nightmares for years.

[leftbrainstuff]

While previous comments are all valid the question you need answering is how much noise are you prepared to put up with and for how long.

Noise is a complicated thing to minimise. You have airborne and structural noise paths, excitation of other components and superposition to deal with. What sounds quiet at a boat show may have annoying resonance when installed.

The quietest genset will be the one not running.

[a64pilot]

OK, use would be to provide comfort while doing local sailing in the heat of a Florida Summer, I.E. run the AC when it's 95F and 90% humidity. Not much other than that, I assume 12V and an inverter would give me all I'd need otherwise, but don't see anyway out of the boat being a hot box in the summer

[Cotemar]

Originally Posted by colemj

Ah, that is a different question than your original post!

If weight and size is no problem, I would go Northern Lights. If weight and size is a problem, I would go NextGen. I wouldn't go Fisher/Panda regardless.

But that is just me.

Mark

1+ on the Northern Lights Generators. They are a bit heavy, but very reliable.

Northern Lights, Inc. M673LD3

[a64pilot]

I think one 16,000 BTU Ac is what the load would be. I had thought about dual Honda 2000i's but you guy's have talked me out of them, if I can afford a real gen set that is

[Cotemar]

Honda 2000 generators are great when you’re in a harbor and it’s on eco mode, but when you put a heavy load on them they get really loud and vibrate a lot.

I have a Honda 2000 which I only use a few times a season to heat hot water after being on anchor for 3 days or more.

I hate using it in a harbor on anything but the quiet eco mode, as I hate the noise myself let alone what the neighbors are getting.

[DoubleWhisky]

Installing the water separator in the exhaust line changed my gen from somewhat annoying to almost unnoticeable.
I've a Fisher-Panda, but of German production. No single problem for six years of use, by it was installed at yard by authorised dealer, properly maintained, and serviced by the book. Water separator was installed later, by authorised service. Now it is so quiet, that You can not tell if it is running when somebody is speaking onboard.

[a64pilot]

List price for a Norther Lights 5 or 6 KW seems to be around 12.5 boat bucks, anybody know what one can be had for? Installation, is that something I should do or have done? I'm a decent mechanic and understand electricity pretty well.