NextGen 3.5KW

[thealife]

Good Day,
Im looking to install a Next Gen 3.5 on my cape dory 28
How is the noise? say inside a well insulated engine room?
Im tempted to move up to a slighly larger 5KW Gen simply to have a two cylinder endine which would be a little smoother running IMHO,
I have dealt with these single cylinder diesels on pumps and there is no going around how loud and obnoxious they are,
I am however, Interested to get some real life feedback,
Can you sleep when its running?

Im actually split between this and a honda 2200 in a dedicated enclosure in the cockpit. but this has its own set of problems all together which I would rather avoid

Thanks in Advance

 

[DavidM]

I used a NextGen 3.5 for several years in my MS Pilot 34, but it was in a sound enclosure. It was reasonably quiet and although we never did it I suspect we could have easily slept up forward in the V berth with the generator on powering the A/C.

But a word about noise vs vibration vs number of cylinders:

I don't think there is much difference among 1, 2 or 3 cylinder gensets in terms of noise. It just changes the noise frequency and probably makes it more tolerable with 3 cylinders.

Vibration is another thing. 1 and 2 cylinder engines produce much more vibration than 3 cylinder engines due to unbalanced piston forces. Three cylinder engines are by far the smoothest and I don't think you will find much difference between 1 and 2 cylinder engines.

In so far as the Honda inside a sound enclosure, how are you going to cool it? The Honda is air cooled and needs good air circulation for cooling which is almost impossible to do in a sound enclosure.

So my advice is if 3.5 kW covers your power needs, go with the NextGen 3.5. It is a simple, rugged generator that runs at 2,800 rpms to keep sound and vibration at decent levels.

David

 

[Pete Meisinger]

You will not make any friends with an air cooled Honda buzzing away on your swim platform.

I don't think a 5 KW on a 28 Cape Dory is a very good match either, Will you have enough room for it?

Boating is a compromise, you probably should go with the 3.5.

pete

 

[thealife]

Compromise compromise compromise haha story of my life

The idea was to make a nice sound insulated teak box with an IP67 fan on the side to force fresh air across the gen, but yeah I hate the Honda boats at anchor as much as the next guy, however, it's very cost efficient,

 

[diver dave]

The nexgen sound shields have a 3” outlet diametrically opposite cooling slots on the input side. Today i am installing the blower and fusing/cabling on my 5.5.

You still need to worry with hatch cavity ventilation. Gotta move air past the gen head that is under 40 deg C.

Nextgen folks told of a 9 dB reduction with the SS. My offhand observation is the 5.5 without SS, sounds about same as my honda 2200 with eco off.

 

[backinblue]

Talk about a first world problem. "When I'm sleeping on my yacht, the generator that supplies air conditioning is too loud for the neighboring boats". lol, sorry, couldn't resist.

 

[HTurner]

Talk about a first world problem. "When I'm sleeping on my yacht, the generator that supplies air conditioning is too loud for the neighboring boats". lol, sorry, couldn't resist.

I believe (in fact I know) there are boats in the second and third worlds causing the same problem for neighboring boats.

 

[thealife]

Nothing like a constructive forum discussion...
No facts or questions, straight to the guillotine!!

We have two Australian shepherds and I like spoiling them, also live in south Florida, the places we cruise are crowded by larger yachts, 9/10 we don't run ac or gen but want the "luxury" of having it for those windless summer nights in Florida/Bahamas
I don't have the luxury of time like most of you, my days onboard are precious, if having HVAC means my family and dogs can enjoy it that little bit more then so be it!

Sorry not sorry

 

[backinblue]

To be clear, I was joking! Did you miss the "lol"?

 

[Carova]

I have a 3.5KW Nexgen on my Cape Dory Flybridge 28. It is in a sound shield. I am in the process of upgrading the venting pipe and fan to a larger unit , since I burned out two capacitors, both times after running the genset over twelve hours. The best diagnostic we could find was that the unit was overheating. When I disclosed the fan cooling capacity at the vent, we discovered it was pretty undersized. It was that way when I bought the boat, but it has worked really well

most of the time. It is pretty quiet under the floor, and seems like it sips fuel.

 

[diver dave]

i just installed a 5.5kW NG myself. Note that the powered fan only forces cooling air out of the unit. You also need to insure make-up air is available. Otherwise the system will overheat no matter how big the exhaust fan is.

 

[Carova]

my engine room is well vented to the outside. Went from 46 CFM to 120 CFM, should do the trick according to Nexgen. I also purchased larger core capacitors, still 425 max V at 40 MF. (a great deal for these, look on ebay) He felt it was not necessary to relocate the capacitor, in light of the modifications. I also upgraded the ducting, using 3 inch turbo inlet (very much stiffer wind and material) instead of the plastic dryer type hose that was on it.

 

[rgano]

I echo David's post number 2 for noise/vib. My 3.5 NG is enclosed in a factory box which I lined with Sounddown instead of the factory foam. It produces a nuisance putt-putt-putt at the exhaust which could be reduced by installing one of those exhaust separators. The first 3.5 NG in this boat (ten years old when I bought it) was a hard starter which just got harder over a year's time and finally seized. That was after the crap Jabsco exhaust fan seized and burned up the entire wiring harness because it had no fuse. Funny that the new harness came with a FUSE. This was a factory install job with the unit having little use by the previous owners. I sent the seized unit to NG in Jacksonville, FL and ended up buying a new one at a reduced rate rather than having the engine rebuilt and dealing with all other parts being 10 years old. They pulled and sent me every removeable piece from the old unit giving me a large box of "spares." The local starting feature which came with the new genny is a nice feature for me because I freshwater rinse it after use and can stand right over it to start and stop it as well as the shore water hose connected to the intake hose via a tee. I also installed a temperature gauge using one of the 1/8" NPT plug openings in the heat exchanger. I found that in our 90F summer waters the unit runs cooler if I use a 30% ethylene glycol coolant mix as recommended in the manual. I had been using the same ELC red coolant as I use in my Yanmar 315 HP engine, but the genny did not seem to like that. Like my 7.5 KW 2-cylinder Onan in my Graad Banks, this NG 3.5 had a noticeable grunt whenever my 10 KBtu AC unit's compressor cycles on, and it tends to keep me awake - that is until I installed Micro-Air soft starter microprocessors on both my ACs - no more thud from the AC unit or grunt from the genny. BTW, I have a 13 KBtu rooftop AC in addition to the 10 KBtu marina unit, and the NG 3.5 runs them simultaneously with the soft starters - would not do that before the soft starters. When I got the replacement NG 3.5, I consulted with NG about the cooling fan and ended up placing a Vents 120-Volt brushless fan (wired to the hot terminal at the capacitor) to pull the hot air out of the electrical end. I put a 30-second delayed start switch on the fan to protect it from all the initial voltage hash as the genny starts.

 

[thealife]

I have a 3.5KW Nexgen on my Cape Dory Flybridge 28. It is in a sound shield. I am in the process of upgrading the venting pipe and fan to a larger unit , since I burned out two capacitors, both times after running the genset over twelve hours. The best diagnostic we could find was that the unit was overheating. When I disclosed the fan cooling capacity at the vent, we discovered it was pretty undersized. It was that way when I bought the boat, but it has worked really well

most of the time. It is pretty quiet under the floor, and seems like it sips fuel.

Do you have any pictures of the install that you could share with me please

 

[Arc]

YouTube

This is my unit . I do not have a sound shield on it. 61 db in the cabin

 

[Carova]

I can't seem to locate any, sorry.

 

[Arc]

Side view of 3.5
https://youtu.be/P2oEYuGOZQM

 

[diver dave]

The 3.5 has an interesting motor. Coolant cooled but has no coolant pump[emoji848]

 

[Arc]

The 3.5 has an interesting motor. Coolant cooled but has no coolant pump[emoji848]

Convection . Heat rises to the top . The heat exchanger cools it and maintains a stable temperature.