Generators Diesel/gas what's the deal?

Don S/V ILLusion · Nov 19, 2008

Maine Sail said:
You're likely going to need a bigger generator for a 16K BTI air conditioner. The EU 2000 Honda is MAX rated meaning short spikes to 2000 watts. The nominal rating is 1600 watts. A 16K BTU air conditioner that needs a 30 amp breaker will likely draw, when running, between 1350 and 1650 watts. This does not take into account any inrush start up loads which the generator may trip on. The EU 2000 has a 20 amp circuit your airconditioner needs a 30.

This is an often quoted as fact I've read before but is a fallacy.
I have no problem running a 16k unit off the H2000. The only real issue is start-up current which many of the contemporary units effectively minimize with a soft-start cap. If it is a problem, it is limited to some segment of the market's older units which can be easily retrofitted.

Stu Jackson · Nov 19, 2008

Don S/V ILLusion said:
Bill

There is a saying that applies to your logic -
"marriage is a 50/50 proposition"

Don, the way I heard it was "you can't live with 'em and you can't live without 'em."

Attributions are --- it works no matter which gender says it!

Maine Sail · Nov 19, 2008

Don S/V ILLusion said:
This is an often quoted as fact I've read before but is a fallacy.
I have no problem running a 16k unit off the H2000. The only real issue is start-up current which many of the contemporary units effectively minimize with a soft-start cap. If it is a problem, it is limited to some segment of the market's older units which can be easily retrofitted.

What part of that was quoted as fact and what part were you referring to? Yes an AC with a soft start cap will probably work. As an owner of an EU Honda I can assure you I have tripped mine before with start up loads and also that it does not like to run for long at anywhere near it's max capacity without getting very hot.

Here is what my EU owners manual actually says: "Power levels between
rated and maximum may be used for no more than 30 minutes. Exceeding the time limit for maximum power operation or slightly overloading the
generator may not switch the circuit protector OFF, but will shorten the
service life of the generator."

I used words like "may" & "likely" because all I knew is that his AC requires a 30 amp breaker, per his statement, and the Honda has a 20 amp. It "may" work and it "may" not and if it does he'll be limited in what else he can run in terms of load when the AC is on. We used mine to remodel a friends camp and we tripped it quite frequently running standard power tools.

Either way 16K BTU is a lot for a 30 footer and he could certainly get away with a smaller AC and still have room left to charge the batteries and run the fridge while also running the AC. I cool a 576 sq. foot room with a 8k BTU unit..

Maine Sail · Nov 19, 2008

Hermit Scott said:
Also is that heater mounted on your bulkhead a propane heater?

Yes it's propane. It does get hot up here but the killer is the 90% humidity that makes 80 feel like 110. In the spring and fall we occasionally need heat. I don't really use that heater very much as it tends to put out more moisture than it does heat. I will eventually replace it with a Dickinson sealed combustion unit..

Benny · Nov 20, 2008

No need to re-invent the wheel, purchase portable gas generator like the Honda 2000eu which already has a built in inverter. Assuming a typo to run a 16,000 btu A/C you may need to add a hard start capacitor to help kick the compressor on; after that it should be cool running.

TimCup · Nov 20, 2008

Hermit, and Benny, them union fellers just don't git it-

the humidity makes 80 feel like 110? C'mon, Sail, you're not gonna tell me your humidity is worse than ours, are you? We're SURROUNDED by water, not Canada!!

Seriously, under the bimini, and at 5 knots in a reaching breeze, I'm still soaking wet in minutes. And that's May. I don't know anything about sailing up north in the dead of winter, but if you sail, you must use heat, right?

Air conditioning is an absolute must in the south (at least for some of us), and here's why-
you can take a dip during the day, but I cannot sleep when it's 85 degrees and 90 % humid!

Hermit, I do agree with Maine Sail that 16k is a big ac unit. I had a 10k on my Hunter 33 (set up under the bed in the bow by a refrigeration guy!), that worked perfectly with a Honda 2000.

cup

fredr · Nov 20, 2008

Re: Hermit, and Benny, them union fellers just don't git it-

I had a Hitachi 55 amp alt on my Yanmar 3gm30.
An identicle alt that is 70 amp can be purchased from NAPA.
It bolted directly on, and the wiring / plug in conection was also identicle. I may have had to clock the housing, (not certain) I have a longer belt because I pivot it a little further from the engine to get more belt / pully contact. A good v belt needs to be used. I understand that many folks want a marine alt / starter, and one needs to make a choice based on their comfort level.
It works well for me with 3 group 31 batteries.
BTW it is OEM for an 1986 Nissan Stanza wagon. You can view it on the NAPA site.
I have heard folks say not to lug a diesel, not to idle a diesel, not to run it on a light load for extended periods...
Idling and light loads - on a pump / nozzle system with over 2300 psi nozzle brake pressure, the fuel is more of a fog or a mist, it does not find its way into the lube oil unless a nozzle is peeing. If the fuel was not being completely burned, you would see it out the exaust in the form of smoke.
Lugging - keep the engine temp under control and, especially in a marine application with a soft load and relitively constant speed, it is rare to see a failure due to lugging a diesel. Shorter engine life when a heavy load is constantly applied?
Yes, certainly that will be the case.
All the emergency gen sets, (kind of the same application) I have ever worked on, have 8 seconds to start and have the load transfered. They either run all out or with no load. A few have a block heater, possibly a 2 to 5 psi oil pressure system, but still, from 0 to 1800 rpm and a load applied in less than 10 seconds is a pretty rough environment. How often have you seen a front end loader, where all day long the operator pulls the engine RPM way down pushing into a pile?
My point is, if you service, PM, and care for your engine, it will last a long long time.
Although I totally agree that A/C is for times at the dock, as far as running a gen set on your boat to run A/C, what about running it off LPG?

fred

Don S/V ILLusion · Nov 21, 2008

Fred
Idling or lightly loading a diesel for a period of time sufficient to recharge a reasonably sized battery bank, especially with a 55 - 70 amp alternator causes piston glazing, not the things you mentioned. Also, the difference between a 55 and 70 amp alternator is negligible, i.e., not worth the effort to change as the real charge current available from each is essentially30 to 35 amps (at idle or a low rev, particularly with a partially charged bank)) or a 5 amp/hr difference.

Or, to put it in different terms, it's all about the charge controller/regulator, not the alternator.

Bob S · Nov 21, 2008

Don,

How long would you have to idle before piston glazing begins? I always thought a tractor diesel or any diesel for that matter was almost indestructible. Every time I see a bus in a parking lot they are idling, sometimes for hours.
As far as alternator go I've seen the charts showing their output. It seems they don't get near their rated output until 3000 rpm. Idling won't produce much charging output. Is it possible to put a smaller pulley increasing it's RPM verses the drive shaft pulley? I never run over 3000 RPM for more than a few minutes. When cruising under power I'm usually between 2000-2500. I assume most alternators can safely run 4-5K.

Don S/V ILLusion · Nov 21, 2008

Bob
That's my point regarding using an alternator to recharge a battery bank - it takes forever because of:
1. the slow charge rate esp at low rpm,
2. when hot, or
3. when the batteries won't accept a bulk charge to be an effective alternative unless both the alternator and especially the regulator are retrofitted to accommodate that option.
Most stock alternators and regulators are inadequate and the big alternators are sometimes too large and cause a large demand on a relatively small marine diesel.

Truck diesels can exhibit the same problem, however, according to my diesel mechanic who spent his entire career working on both marine and truck engines advises, they are different animals in that they are usually much larger and their nominal run time at varying degrees of full load for prolonged periods minimizes the effect. It's an apples v. oranges comparison of small marine v. large truck diesels.

He is also the guy who provided the pictures we all see on the yanmarhelp.com site, some of which show the effects of piston glazing due to prolonged idling.

You have struck the bell regarding the charge curve for stock alternators.
They are essentially ineffective at recharging at idle. Trying to install a larger pulley wheel to increase alternator rpm to offset low engine rpm is beyond my novice comprehension.

Intuitively, I suspect we are discussing something the design engineers have already optimized for the variation in engine rpm expected and if you found a way to increase pulley diameter, the unintended consequence I imagine would be over-revving at high engine rpm. If you look closely at some of the output curves, I believe you will find you can achieve reasonable output from most stock alternators at a mid-rpm range.

I guess, for us at least, this is the season to be discussing operation issues vs. sailing issues.

Maine Sail · Nov 21, 2008

I think part of the reason we hear so much complaining about engines and engine re-builds in sailboats is short run times! Among the things already mentioned starting your engine creates internal condensation and if you don't run it long enough to burn this off it can be very detrimental to your engine. I have spoken to more than one diesel mechanic who feels that condensation in the oil,and the moist bilge air are bigger contributors to glazing than idling with no load.

My buddy Daren owns a large landscape, excavation and irrigation company. Some of his smaller diesel have as many as 5000+ engine hours on them with no rebuilds!! Most of these engines are either Yanmar or Kubota and on the bigger stuff Cat or Cummins the same as in boats. The difference is that Daren's engines run from sun up until sun down...

These engines also idle for LONG periods of time each day with no loads, rather than being shut down, and none of them ever develop the dreaded "glazing" of the cylinder walls we hear so much about in boats.

I actually asked him about glazing and he said "what?". No rebuilds, no excessive consumption of oil and the main difference is that he runs them day in day out. He has over 30 diesel engines in his fleet, with about half of them being identical blocks to what we have in sailboats, most of these engines have over 3k hours on them and some have over 5k..

Our boat is a perfect case study for a real world application;

She spent almost six years as an "on the hook" full time cruising yacht with the previous owners who are friends of ours. The Westerbeke engine is less than 8 years old and now has almost 2900 hours on her. Oil analysis comes back nearly perfect and she burns no oil and I barely even have to clean soot from my transom. Most boaters consider an engine with 2900 hours of use dead. I can assure you this one is just "broken in".. A good majority of those engine hours & time was spent at IDLE while on the hook. No glazing, no issues but the one thing Norm, the PO, and I ALWAYS do/did is to run the engine long enough to burn off any start up condensation. If my engine starts from cold it runs for no less than 30 minutes.

In terms of high dollar alternators;

As I said above the boat we own now was cruised full time for 5+ years as a 24/7/365 "on the hook" vessel. She has a 72 amp factory Westerbeke alternator with "dumb" regulation.

The previous owners got six years and 2700 hours of engine run time out of three group 31 12v wet cell batteries. The batteries were not top shelf either and were Wal*Mart deep cycles.

They were still going strong when I bought the boat..

Personally I think the hype about high dollar regulation is a little over blown for the amount of run time engines see in coastal cruised sail boats. In all the time I owned my multi-stage regulators, four of them, I only once, after a ten hour run, saw the volt meter actually dip to a 13.4 volt float stage and then when the auto-pilot reacted it snapped right back up to the absorption phase.

If you leave it plugged in at a dock you should definitely have a multi-stage charger. For general weekend coastal sailing I find that the multi-stage alt regulators stuff is a bit of overkill in most situations. If it makes you happy, and comfortable, by all means spend the money and do it.

Remember and know though that two adults lived aboard our boat with a "dumb" regulator and an 80 watt solar panel, with no LED lighting except for the anchor light, for over 5 years and the batteries, cheap ones at that, lasted until I purchased the boat. I only replaced them out of my own personal comfort level.

I will not be rushing back to a "smart" regulator unless I head offshore for extended periods. Considering I have had three complete failures of Balmar regulators, two ARS-4's and one ARS-5 I will be considering another brand when that day comes as they did not stand behind the product when I had these failures.

The bottom line is that you need to do what makes you feel comfortable. If not idling your engine makes you feel good even though you shut it down within five or ten minutes of a cold star then that is your comfort level.

I used to buy into "upgradeitis", and spent gobs of money doing so, but then the PO, an electrical engineer by trade, put me in my place when looking at our current boat.

"Wow Norm you lived aboard for almost six years and never upgraded the alternator & regulator from stock? Why would I? Go ahead and load test those batteries, and run em through the ringer, and then look at the engine meter hours and if you're still convinced you need one be my guest and do the upgrade..."

While I fully agree with the "theory" and the science behind multi-stage regulation I still have not upgraded. For the last two seasons my charging has been more than sufficient and my batteries are performing great. Even with the solar panel they have only needed water once per season..

sailingdog · Nov 21, 2008

A good majority of those engine hours & time was spent at IDLE while on the hook. No glazing, no issues but the one thing Norm, the PO, and I ALWAYS do/did is to run the engine long enough to burn off any start up condensation. If my engine starts from cold it runs for no less than 30 minutes.

This applies to all engines, marine or terrestrial, and is good advice in general IMHO.

Don S/V ILLusion · Nov 21, 2008

Maine Sail said:
My buddy Daren owns a large landscape, excavation and irrigation company. Some of his smaller diesel have as many as 5000+ engine hours on them with no rebuilds!! Most of these engines are either Yanmar or Kubota and on the bigger stuff Cat or Cummins the same as in boats. The difference is that Daren's engines run from sun up until sun down...

These engines also idle for LONG periods of time each day with no loads, rather than being shut down, and none of them ever develop the dreaded "glazing" of the cylinder walls we hear so much about in boats.

I actually asked him about glazing and he said "what?". No rebuilds, no excessive consumption of oil and the main difference is that he runs them day in day out. He has over 30 diesel engines in his fleet, with about half of them being identical blocks to what we have in sailboats, most of these engines have over 3k hours on them and some have over 5k..

.

The above scenario is probably more reflective of the way in which his engines and truck engines are run compared with a typical marine diesel. I'm not sure but I'd bet a large number of folk's engines never see more than a couple of hundred hours/year, if that. Running an engine infrequently such as this will exacerbate the effect of slow idling compared with an engine which has many hours at high temperature. Farm equipment and truck engines undergo a substantially different duty cycle which I believe make any comparison questionable at best.

With respect to the cause(s) of piston glazing, I'm in no position to argue other than to refer back to the engine manufacturer's knowledge base with which anyone can feel free to disagree. The cause of glazing being attributed to condensation is something I've never heard nor can imagine a scenario in which this occurs.

If you know, I'd be interested to hear how.

fredr · Nov 21, 2008

Don, I think I have seen the gentleman's posts you are refering to. Very sharp guy.
He is the one who figured out that someone with engine smoking problems had miss adjusted the fuel screw , not RPM, on a Yanmar.
With regard to glazing. Cylinder wall glazing used to be a big problem with running engines under light loads. Not enough heat in the cyl, nor enough piston ring pressure against the cyl wall would polish the wall so that a film of oil needed to seal between the rings and wall would not exist.
With ring packages these days, it is rare. The rings have a step on the inside upper edge of the ring. Compression gets trapped there forcing the ring against the wall.
This is why you do not see much oil consumption as in the old days.
I agree with mailsail, that the hardest aplication can be where you do not run the engine enough to evaporate condensation . It is hard on the oil and exhaust system.
I think however, we would all agree that these Kubota & Yanmar engine are nearly bullet proof.
A Diesel fuel system that has a seperate steel line going to each injector, (technically they are nozzles,) is a pump, line, nozzle system. The pump controls timing and fuel quantity, and the nozzle causes pressure. Kind of like a nozzle on the end of a hose. We used to call them jerk type. Smaller engines are set up this way, but larger diesels have almost all gone to a common rail system. Where a pump supplies fuel at a constant pressure and a injector, valve train, and electronic solinoid control timing and pressure.
There may not seem like much of a difference between 55 and 70 amps. It is however nearly 50% increase.

Maine Sail · Nov 22, 2008

Hermit Scott said:
Maine Sail said:

The bottom line is that you need to do what makes you feel comfortable. If not idling your engine makes you feel good even though you shut it down within five or ten minutes of a cold star then that is your comfort level.

Click to expand

That makes no sense to me. You can feel good about eating fast food cause everyone is doing it, but it's still poisoning people. Rather than feeling good people should seek to know what is going on. But I guess you would sound like an a-hole saying ' HAY! You're ignorant! FIX IT!

Clearly what I wrote did not come out the way I meant it.

Every sailor has a different comfort level whether it be sail inventory, ground tackle, oil change intervals, maintenance schedules, fuel filters, UV protection on and on, and on. Each sailor has to personally decide through their own research what is comfortable for them and what won't have them worried all the time about a gear or other failure.

I know what has worked for me over time and have developed my own personal comfort levels. For example I change my engine oil every forty to fifty hours without exception. I did this even when I ran commercial boats which required oil changes about once every 10 days or so. Most boaters would consider me crazy for doing so when even the manufacturer says 100+ is fine but it is my own personal comfort level. I've never had to rebuild any marine engine that was mine, even after putting a combined thousands & thousands of hours on them over the last 35+ years. This has helped me define my own comfort levels....

I have my level of comfort for boating concerns and you need to find yours. I just happen to have a very high comfort level around the idling of my engine under an alternator load or refrigeration load in specific situations. Others don't and it does not make it right or wrong but each person needs to find their level of comfort. I personally don't feel we'll ever know why some engines glaze and others don't though I have not heard of one dying from glazing on this, or the many other forum I scan, in the last few years.

I am not going to try and convince you that you should idle your engine because you then may always have a nagging bite in the back of your brain while doing so that will make you uncomfortable..

What works for me is not going to always be yours, Don's or any other sailors personal comfort level.. That was my point not that anyone is an A-Hole or that you're ignorant...

ITMaster · Nov 22, 2008

For the worthless contribution that mine will be, this is my two cents worth Mr Scott.

Any and all concerns that I have had (which have been abundant due to the lots of discussion about batteries and power and their management) about my set up just got reinforced from Maine Sail's contributions herein this post.

My stock set up from the manufacturer is a Yanmar 3JH3E 40 horsepower with an 80 amp alternator that Yanmar mounted on the engine. In the four and a half years we have had her, we have put about 5000 miles on her. Also, about 1000 hours on the engine. We are on the hook people, I will drop the hook and use the dink to a town dock before I'll drop 50 to 100 bucks for a day or two stay here and there. I have two unnamed 4Ds deep cycle wet cells that came from the factory with the boat. This last year I added an Energizer Marine application brand group 31 deep cycle wet cell to the system. I got it at Sam's club for $65. I have it wired as Battery 1 and the 4Ds are combined as Battery 2.

I don't know what kind of regulator the factory put on the boat, it works so I haven't needed to fix it (if it ain't broke

). I have a Charles 30 amp charger that when I am at the dock at home, I leave plugged in 24/7.

When on the hook, we use the batteries without regard to electrical power mangement and get pretty much 24 hours of use before the need to recharge. We are running a battery opperated refrigerator/freezer, an electric head, two water pumps, shower pump for the drain, lots of lights, TV's, stereo, the nav systems, and lights. My admiral is far from conservation minded; she has many other qualities and traits that offset this weakenss, so I live with it. She drinks enough beer for the two of us since I don't anymore and flushes the head at least once every two hours she is awake. When she isn't on board, I can last 48 hours without a recharge.

So far, I have no problems with my engine, it doesn't use oil and as I used it, my consumption has averaged out at 0.486 gallons per hour. My lube oil analysis has come back with indications of normal wear metals concentrations for the hours of use on it. I also change my oil often like Maine Sail does. I run the engine when in use for motoring at anywhere from 2400 up to 3600 RPMs. Someone once told me to run a diesel like I stole it; since I do, I suspect the exhaust elbow is pretty clean.

Since I have a dinghy with a merc 4 horse 4 stroke, I have to carry gas, unmixed. The EU 2000 Honda was an easy choice, quiet, economical, lightweight, the perfect power supplement to help get my 20 gallon hot water tank heated up in the winter, since my diesel sucking 45 degree water at 1400 RPM while topping off the batteries isn't going to cut it. I run it until I am done with, close the vent cap tightly and stow it below and haven't detected any aroma of fumes. When we drop the hook, it comes top side to get it out of the way. When I get ready to use it, I check the oil, top off the gas and fire it up. For the brutal times during the summer I can fire up the generator to run my cheapo WalMart window mount AC to cool the cabin down and it works like a charm. I find that now that I have the Honda, that I also use it to top off the batteries as well when it is running. I just flip the various breakers on and off so I don't overload it and trip it out. We put it up on the back end of the boat and so far have never had the CO alarm trip from it. We also have always been very careful to ensure that we have lots of fresh air being exchanged in the cabin when we use this generator. I really like the economizer throttle on it which is the only small engine appliance of its' nature that I have seen one on.

For cooking, we rely on LPG and a solenoid valve to run the oven, gas burners and BBQ on the stern.

I carry two ABC fire bottles mounted under each hatch in the lazerrette, one bottle in the companion way next to the engine, one bottle mounted next to where I lay my head in the owners cabin, one mounted at the nav station and one mounted on the bulkhead in the forward vee-berth. I have three others stowed in lockers, one of which I pull out and put on the dock when fueling up. In my line of business for the time being, I am able to swap these out with about 100 others that I have routinely inspected and serviced by a fire protection company that does contract work for me. These are 10 pound bottles, I don't mind the extra weight for the peace of mind and comfort level that they give me.

fredr · Nov 22, 2008

Re: fredr

The moisture is in all air that is in the crankcase. (between the bottom of the pistons and the oil level,) and air inside the valve cover area.
If the engine does not get completely to operating temp, the condensation rises and accumulates on the inside of the valve cover. At and above operating temp the moisture is evaporated and leaves via the vent. That is why crank case vents are at the top of all engines. This is why Marine engines are so hard on engine oil, lack of high operating temps, and short run times.
Engine oil is like Iced tea. You can put only so much sugar in your tea until it no longer will hold it in suspenssion. The same goes for oils.
Diesel engines in transportation applications run 195 to 198 thermostats. The engine computers don't turn on the warning light until 211 to 215. High engine temps = very efficient combustion= good fuel mileage and low emmissions.
Pistons are alum. and silicone. They don't glaze. Get a piston hot enough and it expands, drags against the cyl wall and starts shedding alum. on to the cyl walls.
I do look inside engines.
Although I have not seen an engine fail from glazed cyl walls, as Main Sail stated, I have had engines that sat untouched for so long, that I had to lube the cyl walls because dry cyl walls would not seal to make compression. This was to get it to start.
It was an old Perkins.
I have not conducted any tests on my charging system. The 70 amp alt does a great job for us. Max amp output is not what I am looking for. I need the 25 to 45 at normal operating speeds. A 35 amp alt is providing 35 amps, at very best, at WOT.
Main Sail said it best;
"I have my level of comfort for boating concerns and you need to find yours. I just happen to have a very high comfort level around the idling of my engine under an alternator load or refrigeration load in specific situations. Others don't and it does not make it right or wrong but each person needs to find their level of comfort. I personally don't feel we'll ever know why some engines glaze and others don't though I have not heard of one dying from glazing on this, or the many other forum I scan, in the last few years."
Our individual experiences and discussions helps us all.

fred