Generators. The Good, Bad and The Ugly

OC, the writing is on the wall, fuel cells will replace generators, if not quite yet.

By the way, I think you mean 8 units.

Anyone know what size March pump would work for a 7.5 MDJE?

They make everything from 162 GPH to 1020 GPH. Based just on the size of the outlet fitting, I'd guess the 510 GPH.

My genset has a bolt-on raw water pump, so I wouldn't even need to cover it over with a plate. Just get a new belt to drive the circulating water pump and plumb the electric pump in the intake hose. With a generator and two reverse-cycle air conditioners, having a spare pump that would work on any of them seems like a no-brainer.

JDCAVE said:

Cap'n Bill and Larry and all: Thanks for the "Heads up" on the March Pump. It was the PO install. I was willing to live with it unless it caused damage to the pump. So I phoned March's technical people with the particulars and the fellow said that it could cause damage, depending on the duty cycle and water temperature, so I will remount it. It will require jockeying some fittings around, so will see what I can do.

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As I look at this a bit further, there is more than pump orientation that I should be concerned about. The water lines need to be better supported.

Jim

FF said:

"but I discovered that without current limiting and at full charge rate, the belts stretch and fail very quickly. So I limit it to about 90 amps."

Sounds like an automatic (spring) belt tightener might be on the next NAPA visit wish list.

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Unfortunately, I undersized the belts when I built it, and under full load, they turn to string with a lot of noise and smoke...

90 amps at nominal 24V (28V when charging) is plenty to recharge quickly or run a hairdryer, vacuum cleaner etc and even a small fan heater in winter.

Bendit said:

Unfortunately, I undersized the belts when I built it, and under full load, they turn to string with a lot of noise and smoke...

90 amps at nominal 24V (28V when charging) is plenty to recharge quickly or run a hairdryer, vacuum cleaner etc and even a small fan heater in winter.

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If you can increase the diameter of both pulleys, keeping the same ratio, the actual tensile load on belts goes down for the same amps produced. Also increases the contact area of the belts, which helps further.

Xsbank said:

OC, the writing is on the wall, fuel cells will replace generators, if not quite yet.

By the way, I think you mean 8 units.

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Nope, no mistake, each unit produces 107 watts. My 8KW genset produces 8,000 watts. Need 80 units.

Ted

O C Diver said:

Nope, no mistake, each unit produces 107 watts. My 8KW genset produces 8,000 watts. Need 80 units.

Ted

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Ted is right. The fuel cell will never replace the diesel generator as the main source of ship's power, at least not in my or my children's lifetime.

The fuel cell units are too expensive and because most use methanol as their fuel which is a very inefficient source of energy, the operating costs are huge.

David

JDCAVE said:

As I look at this a bit further, there is more than pump orientation that I should be concerned about. The water lines need to be better supported.

Jim

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Yeah the fittings on the pump aren't going to be happy with that kind of weight hanging on them. I would also consider replacing all those metal fittings with plastic.

Xsbank said:

OC, the writing is on the wall, fuel cells will replace generators, if not quite yet.

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The big hassle with noisemakers is the builders are locked into existing products by their factory costa.

Honda and others with massive volumes have great gas units that produce DC and use electronics to create the power form desired.

Bendit was able to home brew a modern efficient variable speed unit .

Some day competition will require most of the current antique designs to be scrapped ,

Business opportunity anyone?

FF said:

The big hassle with noisemakers is the builders are locked into existing products by their factory costa.

Honda and others with massive volumes have great gas units that produce DC and use electronics to create the power form desired.

Bendit was able to home brew a modern efficient variable speed unit .

Some day competition will require most of the current antique designs to be scrapped ,

Business opportunity anyone?

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Maybe these already exist; as our Kohler runs well, and not being in need, I've not researched the following.

1. Why not for Honda or Bendix to make easily adaptable marine gen-sets that could be located where existing gen-sets sit in pleasure boats and have control panel in same basic location too.

2. What weight / size would they need to build for it to provide 7 to 9 kW

3. Wonder if their marine sets could still be air-cooled with piped-out exhaust while deep in lower confines of a boat? Water cooling necessary??

Art said:

3. Wonder if their marine sets could still be air-cooled with piped-out exhaust while deep in lower confines of a boat? Water cooling necessary??

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Not likely. An internal combustion engine driven generatorconverts very roughly 1/4 of its fuel energy to electricity, about 1/3 goes out the exhaust and the rest is heat rejected to the cooling system or radiant/conductive losses from the engine block.

So very roughly speaking a Honda EU 2000 running at its maximum continuous output of 1,600 watts is going to dump about 2,000 watts into the bilge compartment where it is located. Think about how hot your bilge would get on a summers day if you had 1-1/3 of the typical 1,500 space heaters running down there.

And then double that number or triple it for larger gensets. It just won't work without active cooling, either above deck where the air can circulate or cooled with sea water below.

David

We have a NL 5 KW in sound box NL is a great generator, we run A/C two 16,000 btu and it handles the load. Last trawler had Kohler 8KW in sound box same as ranger42c and it was okay, by that I mean it strained when the one 16,000 btu A/C came on but kept running. What ever is engineered into the NL works !!

HiDHo said:

We have a NL 5 KW in sound box NL is a great generator, we run A/C two 16,000 btu and it handles the load. Last trawler had Kohler 8KW in sound box same as ranger42c and it was okay, by that I mean it strained when the one 16,000 btu A/C came on but kept running. What ever is engineered into the NL works !!

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Must have been that Kohler...

my 26 year old Westerbeke 8 kw handles 2 - 16,000 btu ACs, hot water heater, microwave, coffee pot, battery charger, and all the other house loads and maybe drops from 120v to 115v and a few cycles....no strain here.

HiDHo said:

We have a NL 5 KW in sound box NL is a great generator, we run A/C two 16,000 btu and it handles the load. Last trawler had Kohler 8KW in sound box same as ranger42c and it was okay, by that I mean it strained when the one 16,000 btu A/C came on but kept running. What ever is engineered into the NL works !!

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Something was wrong with your Kohler or your A/C. There is nothing magic about a NL Genset.

HiDHo said:

We have a NL 5 KW in sound box NL is a great generator, we run A/C two 16,000 btu and it handles the load. Last trawler had Kohler 8KW in sound box same as ranger42c and it was okay, by that I mean it strained when the one 16,000 btu A/C came on but kept running. What ever is engineered into the NL works !!

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If we're running both 16K BTU ACs, and the water heater, both fridges, and maybe cooking, our genset does sometimes slow a bit when one of the AC compressors kicks on. Or maybe it's when both ACs are on but the thermostats haven't actually activated them and the pump's not already running. Anyway, just a quick step, nothing that seems to be of concern.

Wouldn't have thought a single AC would cause much of a burp.

-Chris

The added efficiency of a DC variable speed /inverter setup comes from its minor load ability to match the engine HP to the load.

Running at almost full bore the fuel burn would only be slightly different.

The mismatched installation a 12KW running only the fridge would be helped.

Some folks could do better using the noise maker cooling thru the heat exchanger to create domestic hot water.

Co generation , capturing some of the lost energy for free.

BruceK said:

Pgitug, now you no longer have a blank page on gensets, any supplementary questions?

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After reading all of the posts I am thinking my next boat will have a Northern Lights generator. The boat I just sold had a
Fisher Panda generator. The FP folks really treated us well during the 9 years and 1800 hours we owned it. But after reading the posts I am looking forward to a low RPM generator for both the lower noise and probably a lower operating temperature.
I appreciate the information and experience provided. It sure beats flying by the seat of your pants.

I wouldn't make the lack of a Northern Lights genset a no go item on your next boat. A properly sized and sound insulated generator from Onan, Westerbeke, etc would be fine also. I have an Onan (Cummins) MDKBL in a sound enclosure installed in a well insulated engine compartment. 9 KW and it runs three 12000 btu air conditioners, water heater, cooktop, etc with no problems. It is very quiet and very low vibration. The only thing I wish I had was the exhaust water separator.

My last boat had a small Mastervolt 3.5 KW genset running at 3600 rpm. It was pretty quiet inside its enclosure, but it did vibrate. The lower rpm genset I have now is huge improvement in livability over the 3600 rpm one.

DEUTZ and others make air cooled engines in the 100+ HP range , cooling would be ductwork (12x12 or larger) with a proper fan.

A 4 to 20KW noisemaker would need far less.

The possibility of co generation , using the engine cooling to dry a wet locker , or even heat the boat is possible.

The ductwork would be lined with sound absorbing material to stop noise transfer.

Nothing to winterize , no holes in the boat , and no midnight visits from jellyfish to clear.

Northern Lights only 540 hours 2002 model 8 KW

Our gen set is used very little because of our solar power. But when needed we want it to work. I was surprised when the generator no longer worked and discovered the winding had a shorted circuit due to corrosion from age. Several places in Florida gave estimates of $4-5 K to replace the winding, and related parts. This would be after I removed the 300 pound + unit and shipped it to them. The offers were they would get my old unit armature and coils, replacing them with a rebuilt rewound coil and armature. I would be responsible for new bearings and the labor to remove and replace. A local mechanic was hired to remove and replace the unit at $400. shipping to re builder $350. one way. The re builder Dreisilker Electric Motors Carrollton, GA, 30117 - YP.com
Rewound the armature and field coils, replaced the bearings and shipped the unit back to me in 3 weeks downtime. Cost $1200.
Now 6 months later the set runs good with ample power for two 16K AC and other loads we have. HTH

Next Gen

Moonfish said:

I guess we have the smallest generator on this thread so far... NextGen 3.5kW. Starts/runs like a champ, low rpm, very compact, can only hear the gurgle of exhaust when running on the outside. Not too loud inside the boat, but we don't have a full sound enclosure. Just the sides and top. But I never worry about it running too hot in the ER. Meets 90% of our needs, but sometimes wish we had the 5kW NextGen.

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I installed same 3.5 KW gen set in my Helmsman 38 PH. I only have 15 hours on it, but it seems to be a great unit. Provides equivalent of 30 Amp shore power, and that is plenty for me. Main reason I wanted it was so I could run electric hot water heater without having to run my Cummins QSB 5.9 380HP when at anchor. I don't have an enclosure on it, and it is in my main cabin lazarette. Reasonably quiet. I measured 60 dBA while sitting right on top of it. So far I am very pleased with it.

I generally get my gen ends redone here for about $500. Thats for a 15kw unit. Cooked out rewound, rewired, totally redone like new. No bearings or brushes (if it has brushes) or exciter rewind, just rotor and stator. I take it off, take it to them and pick it up, then reinstall. While the set is out I completely redo the entire thing, all new hoses, rebuild raw water pump, clean entire cooling system both engine side and exhaust, fix any issues it may have had or that I find, completely strip/derust the unit, prime with 2 part epoxy, repaint with 2 part polyurethane. I usually have about $2000 in it when done.

Even though I had an old Onan on a prior boat, and it gave me a lot of trouble (more than one guy told me that mechanics called them "Oh-No's"), I replaced it with another Onan -- an EQD, and for my current boat I spec'd two EQDs. Have never had a problem (even though one is always running when I don't have shore power), and they are so quiet they are literally hard to hear and have zero visible exhaust. And they are served by Cummins (which I have for mains).

1977 7.5 kw gasoline Kohler... sweet baby!

Everything you ever wanted to know about marine generators

https://www.victronenergy.com/upload/documents/VE_Marine_generator_test_RVA_07-jan-2008.pdf

The big key to long diesel generator life, beyond regular maintenance, is to use them.

I've noticed my 3 cyl westerbeke is getting harder to start and I'm smelling a little blow by oil smoke . Probably getting time for compression test ?

Pack Mule said:

I've noticed my 3 cyl westerbeke is getting harder to start and I'm smelling a little blow by oil smoke . Probably getting time for compression test ?

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Those 8BTD and 8WMD had gear reduction starters that barely spun them over fast enough to fire even with a good healthy engine. Make sure your battery and cables are in good shape. Slow crank speed is a common cause for hard start.

Blowby can be checked by hand by pulling off the little tube that goes from rocker cover to intake. Pull it off and if flow is just "wafting out" then rings are sealing fine. If it is blowing hard, then rings are not good.

You should not smell the blowby, it should all be going into intake.

Thanks Ski, I'll check out the blow by . The water is up too high right now and docks are closed. I'm actually getting a burnt motor oil smell out the exhaust like driving behind a car burning oil . Not a diesel smell but motor oil smell .Oil level does not show burning any oil .