Generator or not?

[Ric]

Hello,

I am speccing out my new boat, a 40ft aluminium centreboard sloop which will be home for the next two years.

I want to provide all my day to day 12v electricity with solar panels, a wind-generator and a prop-shaft alternator.

However, I will occasionally need 220v to power my dive-compressor and washing machine. My intention is to install a 220v alternator and sine-wave converter on the main engine, rather than a dedicated separate generator. My reasoning it will be relatively rare that I need 220v and so am prepared to put up with the churning and wear of the main engine when I need 220v as to me it would be preferable to having the hassle of a separate generator.

I know the cheaper solution is to use a generator for all my energy needs and ditch the expensive wind/solar/prop solutions. However, I suspect I would rapidly get very fed up with the rumble of the generator every day, the additional maintenance, and also would miss the satisfaction of "alternative" energy sources.

But before I make a commitment, I little experience of generators on boats so maybe those who have can contribute?

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[Talbot]

I seem to remember a site in the states that had a combined generator/dive compressed air machine - too heavy for me, I have a 180w solar panel and will be getting a duogen. By the time I have changed lights to LEDs, I should be power surplus.

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[steve_cronin]

I agree with your reasoning

...plus 40ft is just about the lower limit for a plumbed-in generator.

The extra wear on the engine would be negligible and bore glazing wouldn't be an issue as the high output alternator (driven by duplex belts I assume?) would provide sufficient load on the pistons. Apart from the engine driven alternator this is my system except that I also run a 1800/2500watt inverter.

the small washing machines fitted by HR (Zanussi FC1200W for example) can be single hose fill so the calorifier will deal with the greatest WM/C load of an immersion heater. The motor load will easily be taken care of by your proposed set up.

Steve Cronin

<hr width=100% size=1>The above is, like any other post here, only a personal opinion

 

[tcm]

um i have fairly good experience of gennies on (power) boats. On the current boat we have two which can either operater separately or in parallel. Space is your main concern of course, but your power reqs already look not insignificant. Mostly they are faily bombproof. The racket is because they are either not properly insulated or run up against another boat, or against the harbour wall.

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[steve_cronin]

Didn't know that was possible. When running them "in parallel" how do you manage to phase-match them?

Steve Cronin



<hr width=100% size=1>The above is, like any other post here, only a personal opinion

 

[tcm]

They do it themselves, it seems, i think. The second genny starts off all rattly, and then gradually takes up the load and it's shared between the two, or at least, that's how it reads on the dials. I take no credit for this clever arrangement and in fact only recently realised that i could run both at the same time, which isn't really needed unless you absolutely must have 34 kvA.

Back the the question, i wd prefer to have a genny. The moderate rumbling (for less time per unit of power generated) is far more bearable that the screaming wind genny, no?

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[Ric]

Multi-engine aircraft usually have one alternator on each engine driven via a CSU, and the phase-matching is now done automatically (the flight engineer used to have to fiddle around watching blinking lights to match but he got the sack years ago). I presume your boat has a similar auto-synch system.

Thanks for the advice on the noise, but with all respect you are a motorboat person and so perhaps have a slightly different perspective to me regarding acceptable noise and also different energy use patterns. On my current smaller boat I get inordinate satisfaction from getting power from solar and wind, just as I get satisfaction from having my boat move from wind. The idea of having a generator is fairly last-resort, which I would consider only if I was convinced it was the best option by far. And wind generators are not noisy - except badly designed ones!



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[Talbot]

Do have a look at the duogen as this will give you the best free power alternative to loads of solar panels. Your heaviest load is likely to be the autopilot followed quickly by the fridge and freezer. all other loads average out per day at considerably less. Have you done an energy budget yet to investigate exactly what power you need, and then have a contingency plan for things going wrong (watermakers and generators seem to have the highest failure rates!)

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[Ric]

Yes I have done an energy budget and we've already had a long argument about the merits of the duogen! I intend to have two Aero4gens (more output than one Aero6gen and less windage) and a dedicated propshaft alternator. The duogen would not really be suitable for my new boat as it has a rear arch with dinghy davits combined, and a large sugarscoop transom. I also don't like the idea of having only air or water, and prefer lots of back up energy sources in case things go wrong.

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[tcm]

um, with respect i am motorboaty yet sail quite a lot too. In reasonable wind the wind gennies all make a fair amount of noise and it is a quite a high frequency. From the foredeck i can't hear our genny but can hear the wind genrators of a boat 100 yds away. The bearings are highly exposed, difficult to lubricate, and unlikely to be needle rollers which would be quieter (and better-designed!).

Even if the mechanism was silent, there would still be a whoosing noise.

I agree that the self-sufficiency in near-total silence is hugely satisfying. However, given the option of a short amount of time with a genny or sevreal times the duration with the wind generator - i'd have a motor-powered one every time. But space is the prob, i think, hence agree -esp given you are motor-averse - the windmill is probly the way to go.



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[Talbot]

Also thought about going the double aero 4 route, but reckoned it would be so much extra noise. Furthermore we all try to sail downhill when possible, and this is the time when the aerogens are least efficient, whereas the duogen is in the water at that stage - so no noise, and no loss of efficiency! (BTW they will fit on a stern with sugar scoops)

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[ubuysa]

Thanks for the photo, this is the first time I've seen one of these things in the water (I'm kinda new you see). What happens if you get a MOB and do a crash tack with that thing in the water? Looks to me like it'd bend or even break under the sudden sideways load??

Just curious.....Tony C.

<hr width=100% size=1>There are 10 kinds of people, those who understand binary and those who don't.

 

[steve_cronin]

Maybe, but the guy has a sailing boat and so he probably doesn't want electric cookers. We find that our set-up works fine. We use an electric kettle and a toaster most mornings off the inverter (one at a time) and the Sterling regulated 80aH alternator soon puts back the power. The panels (2x 55watt) cope with the fridge which in the med is run at maximum in the summer . (It managed to freeze the milk a couple of weeks ago) The wind genny isn't currently up as we are having a new gantry made but it isn't missed. May not re-fit it as we are now in the Ionian (well the boat is) where the winds in the summer are less than in the Aegean.

Microwaves are another matter but so long as you only use them to re-heat they work out fine. Savings on bottled gas are dramatic.

Steve Cronin



<hr width=100% size=1>The above is, like any other post here, only a personal opinion

 

[Talbot]

no sideways load at all, it is pivoted to move up/down and sideways, and a plate on the bottom of the propellor keeps it submerged.

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[ubuysa]

Ahhhh. Many thanks for that.

Tony C.

<hr width=100% size=1>There are 10 kinds of people, those who understand binary and those who don't.

 

[Keith]

The reason i don't have a genny on my boat (30' cat) is primarily weight, but on most boats (as has been stated) under 40' there is a problem with where to put it, insulation, (sound and heat) also needs to be addressed as does the problems of more oil and air filter spares (unless you are lucky enough to get a genny engine identical to your main engine) another two holes in the hull, probably another anode, personally i just run solar panels,with a good battery bank........keith

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[Dave99]

I know someone who crossed the sailed from the Uk to portugal last year. They could power there nav instruments, RADAR and fridge by towing there duogen -given that the wind was about force 5. They also had a small solar panel. However the boat did not have a washing machine or freezer

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[Moose]

"the flight engineer used to have to fiddle around watching blinking lights to match but he got the sack years ago"

Errr,,,hello!

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[seanwest]

Re: I agree with your reasoning

I have a electrolux travel power that came with my boat, its not going
It has a alternator runing off the engine (has a bosch body but different windings) this goes to a black box. The alternator is not working and a fuse is gone in the black box, not to sure what do? VDO are charging £650 to replace the alternator and the cannot say if this will solve the problem. Has anyone any info/experince which this? Its rated to give 3500w

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[robind]

Re: I agree with your reasoning

Hi Sean! werent these used on land rovers it may also be worth checking with LR and getting the name of their repairers? of course VDO will charge you a fortune thats how they make a living and Land Rover. check out my private post to you
Regards

Rob

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