By DariaBlackwell - 20 Jun 2012
While cruising for several years, we found that one of the most 'lively ' discussion topics among cruisers was, "Which method of generating power works best?" Occasionally, there would be an enthusiastic proponent for one form over another, but more often than not, the discussion was far more complex. I think it might be useful for us to share our experience with different forms of power generation and different equipment options within each category.
So far, we 've learned:
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[/ul]diesel generators are still a very reliable and relatively economical option as long as you can carry enough diesel
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[/ul]solar panels are not as reliable as most would think, especially when the climate tends to be cloudy (Ireland/UK) or days are short (Caribbean) or when parts of the panel are obscured (which can shut the whole panel down)
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[/ul]wind generators tend to be noisy/vibrational and don 't work very well downwind (tradewinds sailing) or in protected anchorages
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[/ul]towed water generators attract BIG fish
That said, we have a diesel generator that works rather flawlessly. Although upon adding AIS, a second navigation system, watermaker, etc, we know we 'll need more power.
We are considering adding a wind generator that can be hoisted into the rigging to catch wind or towed overboard while underway. We are also eagerly awaiting the new generation of solar panels that is supposed to provide a dramatic improvement in efficiency. Does anyone have advice and experience to share that would help us make some decisions on the best gear to add in these departments?
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By robwithers - 22 Jun 2012
A serious contender now has to be fuel cells. They are small units that charge the batteries whenever necessary at low to medium currents (5-10A). They are therefore working most of the time, but since they are so quiet and compact, its not a problem
You can see some installations at:Fuel Cell Systems.
I should add that I haven 't had experience of them myself, but my neighbour has and attests to their efficiency and effectiveness.
One consideration is that you do need high purity methanol. This is available in many places - but not universally (e.g not in Caribbean)
I would be interested to know the real-life experiences of some owners as I contemplate the retirement of my aged, over-powered and noisy fixed, diesel generator
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By DariaBlackwell - 22 Jun 2012
Thanks Rob. Fuel cells sound almost too good to be true. Will definitely investigate.
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By dcaukill - 31 Jul 2012
I agree with your assessment of technologies.
My view is that you should fit as much domestic battery capacity as you possibly can and a simple, proven, diesel generator with the out put to charge them as fast as they will take it (that means a charging current about 25% of rated capacity I.e. A 400 AHr bank can be charged at 100Amps - you will need a smart charger to manage the batteries).
My boat is large, so that I 'd need a big solar array to make any material contribution but wind generation is still an option. however I can get most of the power back into the batteries in the time I need to make water so that I get good efficiency out of the generator.
There is a fixed towed generator made by Witt & Sea (german) (a much smaller version of the Duogen (and without the vane!) that I will look at this winter. It is transom mounted, is said to make a big contribution with little drag. But then I will have to learn to live with less water!
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By DariaBlackwell - 31 Jul 2012
Many thanks for your note David. I imagine we 'd have difficulty with any transom array as we have a Monitor windvane self steering system mounted there. Please do keep us informed of your learnings this winter.
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By gregs - 31 Jul 2012
Our experience found solar to be quite good in most areas when used to top up the batteries and sized to carry the daytime sailing load plus add 30amp hrs. That is to say when used with a diesel generator. Our batteries lasted 9 years they were marine grade gell batteries grp 27. So they were nothing special and only a few were bad but we went to replace them all. On days of little sun we just did not get the batteries toped up as well but then we get some sun and it would top them up nicely. We didn 't see much success with wind or water generators and only solar was usually under-powered. Diesel generators worked great but you need away to add the last bit into the batteries.
best
greg
S/V ErinBrie
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By archive - 22 Aug 2012
We have 400Ah of batteries and a 100Ah charger attached to our generator. With a fridge and freezer we had to run the generator for at least 2 hrs per day on passage to keep things reasonable even although we had a wind generator.
The wind generator would supply about 2/3 of our daily needs when we had more than 20kt of steady wind. Below that (most of the time) its contribution was modest.
2 years ago we installed 440 Watts of solar panels with a dedicated MPPT charger - lifechanging and so liberating! I had to rewire the hot water heater through the inverter so that we could have 'free ' hot water rather than wasting the energy as most days our bank was full by 1pm. (S Bahamas/Cuba area). We can now leave our appliances on and not worry too much.
As important to us is that we now only run our generator for a few hours a week when we need to make water although that will change shortly as I 'm about to install a dive compressor.
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By DariaBlackwell - 23 Aug 2012
Thanks for that. Sounds really good. Would you mind sharing the brands of wind generator and solar panels you installed?
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By archive - 23 Aug 2012
Hi Daria,
We have Trina solar panels, an Outback charge controller and an Eclectic Energy D400 wind generator.
Our solar is mounted slightly lower than I would like on the davits and so they are partially shaded until 8am or so in winter but they perform admirably. I recall that our best day ever was 2.7kW of solar input - the wind clocked from W through N to E! Nice to see the batteries on float!
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By Blueprintbill - 3 Sep 2012
Water towing generators attract big fish ? Has anyone ever had a fish attack one ? It would have to be one hell-of-a big fish ! I towed one trans-atlantic west to east with only great success. Pulled it in when we started the engine and got a tangle of the line, which when disconnected from the generator and dumped back into the water in the reverse order it was brought in ( hanging onto the propeller ) it would promptly sort itself out. A great bit of kit, kept us on batteries powering radar, lights, SSB, etc. no problem. I love the thing.
Bill R.
SV Blueprint
Nicholson 31-113
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By alshaheen - 5 Oct 2012
I also have had great results from an Aquair towed generator on long pasages. It gives me about 6 amps at 7 knots. The only problems are securing it on the rail and the difficulty of recovering it without almost stopping the boat.
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By mikeaclark - 19 Oct 2012
Our experience has been similar to the above comment. In our first boat with minimal electrical demands (no freezer, water maker or washing machine) a good battery bank and solar panels and our big alternator on the main engine worked fine. I never used a wind generator for 2 reasons: first they make a lot of noise and second we have been in anchorages on 3 occasions where they shed their blades and in doing so caused significant (but so far not lethal) injury requiring hospitalization twice and major damages to another boat nearby. Few mention the safety hazards associated with wind generators but a 3 foot plastic blade rotating at high speed in a 25 kt wind will go a long way and hit very hard and nearly always where no medical help is available.
However, once we moved aboard our second boat full time things changed. Our electrical demand is much higher and an even larger battery bank and alternator for the main engine is ok while under power but there simply was not enough room for an effective array of solar panels. A diesel genset harnessed to 2 big battery chargers putting out 25% total battery capacity works great. We usually run the gen set either once a day for 1 .5 hour, or every other day for 2 hour. The output is sufficient so we can power a 26 gal/hr water maker and the clothes washer and charge the batteries at the same time. I may be wrong here but in my own opinion I think many of the problems with diesel gen sets result from them not being used frequently and I believe this is why som many small boats with diesel gen sets fail. Diesel engines and water makers both benefit from frequent if not near daily use. Our 25 kw gen set burns 0.6 gal/hr and once a year preventive maintenance results in a lot of energy.
s/v Waterwitch
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By cverlaque - 23 Oct 2012
It looks like with solar panels, wind generator, towing generator and diesel generator you have covered all the energy sources on a boat. We have used those 4 at different moments and each has it 's own window of use. While under way we have found that the solar panels and water towing generator have been the most efficient. Our solar panels are located both on starboard and port side of the boat allowing us to have most of the time one panel giving us close to full output. The towing generator is a very good source, 5 amps at 5 knots. Only problem is to bring is back on board. I had to literally stop the boat as the torque was to hard on the rope (and my hands). Some people have suggested to rig a big funnel on the line and to drop it in the water in order to stop the twisting of the prop. I have not tried it yet, but it make sense. Anyway, I think that by having the 4 systems on the boat you should always have a source of energy. Good luck, christian, s/v I wanda
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By jgbailey - 20 Feb 2014
Has anyone ever had a serious problem with BIG FISH attacking a towed generator? I ve never had a problem.
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By jgbailey - 20 Feb 2014
Has anyone ever had a serious problem with BIG FISH attacking a towed generator? I 've never had a problem.
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By Blueprintbill - 20 Feb 2014
JGBailey,
As I had mentioned earlier, it would have to be a hell of a 'big fish ' to go after a towing generator blade, and then it would regret it ! Think Great White Shark or Killer Whale.
It 's more myth than any reality. :silly:
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By alshaheen - 21 Feb 2014
I was using an Aquair towed generator on an Atlantic crossing and lost the impeller. The line was severed just ahead of the impeller and I assumed that it must have been a big fish that took it. They was no reason for the line to have chafed at that point.
John Franklin
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By Frederic Aujard - 2 Oct 2014
Frida, our Ocean 60 has a Watt & Sea hydro-generator fitted for 2 1/2 years.
It provides all the energy we need and much more, above 7 knots.
I could cross the Atlantic twice, forgetting the freezer (yes, we had ice creams in the middle of the Atlantic), fridge, auto pilot and so on...
We could freeze the gigantic wahoo catched on second day, and enjoy it up to the Azores.
I can 't remember using the diesel generator during passages !
Really a revolution in cruising, not only for Vendee Globe racers !
Watt & Sea is a small French start-up, from La Rochelle, my home town.
There are two different models for cruisers, one for lower speeds, and the one I use for speeds between 6 and 10 knots (up to 20).
No concerns with big fishes !
Our wind gen. is a D400, it could top up batteries in windy trade wind anchorages (steady 20 knts), with only one fridge in use.
Not bad, but with lighter winds, we had to set the diesel gen. up for one hour or two each day. Noise is not a concern, something like a light "woosh", not the terrific whistleling of others.
Our service battery bank is AGM, 450 Ah 24 V.
I carefully monitor the bank voltage, and start charging when 24.8 V is reached.
We use two 50 A Victron Skylla chargers in parallel for quick charge.
If shore amps is poor, or diesel gen busy we only use one charger (8 A)
Charge voltages are adjusted to the batteries and temperature...
No solar pannels...
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By dcaukill - 2 Oct 2014
Interesting.
I am aware of a number of boats with this Watt & Sea kit. Some, smaller than your boat, have had difficulties with the mounting on the transom which has failed - and has now been remade in thick stainless steel.
Did you do any modifications to yours when you fitted it?
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By alshaheen - 2 Oct 2014
I saw one of these installations on one of the boats in the pool at the recent Southampton Boat Show. The mounting system looked to me to be very lightweight and my initial assessment was that I would not trust it in heavy weather conditions. In heavy weather there will be a large shear force on the transom mounting caused by the transom moving laterally in relation to the water as the boat falls off a wave.
The performance looks excellent; only the mounting concerns me. How does the mounting on the "cruising" version compare with that of the ocean racing version, which is presumably well tested?
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By Frederic Aujard - 2 Oct 2014
I never heard of any problem with the mounting.
The forces are not so important you can imagine.
The all system swings left and right with the water stream, and never resist against it.
I have tested the W&S in heavy following seas, with 10 knots + average speed, surfing the swell at 15-18 knts, nothing failed !
The only point is to fit a very powerfull pulley block (4:1 at least)or you 'll have to stop the boat when hauling down.
Should be wise to fit a "fuse" on the cleat in case of any encointer with an unidentified floating object.
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By Frederic Aujard - 2 Oct 2014
I just trimmed two heavy plastic (nylon) blocks to keep the mounting vertical, as transom is a nearly vertical classic.
Fitted with X 4 8 mm screws and bolts, with large washers
Lifted, the W&S stays vertically , under rear platform, well protected.
I never remove it.
I understand that in some cases, a special mount must be added to the transom, somehow like a wind vane, but smaller and lighter.
The manufacturer has many exemples of mountings on different transoms.
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By DariaBlackwell - 2 Oct 2014
Have just heard from a very reliable friend that something chewed their towed generator off mid-Atlantic. They never did see what it was but did know there was a struggle.
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By simoncurrin - 4 Oct 2014
Thank you Frederic I had not heard of this piece of kit before. I have pasted below the link to their price list: http://www.wattandsea.com/sites/default/files/2013-2014_Price%20list_T6%20EXW%20GB_V2.pdf
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By Frederic Aujard - 4 Oct 2014
Simon,
It was not a kit, I made it myself !
I suggest, if the transom is far away from vertical, to realize a special bracket (made of GRP, Aluminum or SS).Exemples here : http://www.wattandsea.com/sites/default/files/exemples%20de%20montages%20cruising.pdf
This bracket could stay on the transom, but you can remove easily the W&S, using this : http://www.wattandsea.com/en/content/removable-support
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By AQUALUNA - 21 Oct 2014
I am having a Discovery 58 built ( to replace our 55 destroyed in a fire last year) and have specified both Watt and Sea Hydrogen and hopefully 600 watts of solar panels on the davits to reduce dependence on the generator. Any other ideas about makes/types of solar panels?
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By simoncurrin - 21 Oct 2014
Not sure about davit mounts but we are going for Solbian than zip into the Bimini or cockpit tent. http://www.barden-ukshop.com/solbianflex-sp100-l-flexible-solar-panel-2914-p.asp
Simon
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By Dick - 21 Aug 2015
Hi everyone,
In my experience, if you wander widely, there are 2 considerations that compel one to consider a genset: a large freezer and the wish to have aircon at anchor. If you can live without the former items (or just do not have them, most cruising boats can get along fine with solar and wind battery charging (and probably both are necessary).
If you go for a genset, I would suggest that one not complicate your cruising lives further by adding solar and/or wind. My reasoning is as follows: one, diesel generators (diesels in general) like to be used regularly and used hard. Having your batteries partially charged by solar/wind undermines that goal. Solar and wind are complicated installs, (physically and the electrics and the black boxes), expensive, are often in the way and need an eye kept on them: why not simplify by having just a genset and run the genset an extra short period of time (15 minutes might be enough) to make up the difference. The weight saved (and complications) can be put into extra battery capacity which will serve you better in the long run.
The most sensible genset is one that produces only DC and charges the batteries on a boat directly with AC coming from an inverter (hopefully one does not have AC refrigeration). Unfortunately, there are no reliable ones on the market. (I have one and have made it work for us for over a decade now, but it has been a struggle.) AC gensets are far more reliable, if the installation is impeccable and maintenance is good, but it often takes long run times if all they are doing is charging the batteries (modern chargers may have improved this function).
Enough for now,
Appreciate any thoughts,
Dick Stevenson, s/v Alchemy
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By Alex_Blackwell - 21 Aug 2015
Thank you Dick
we have been pondering this question for years, wishing to be greener. Wind generators all seem quite loud, and solar has up to now been tricky and iffy. The latest panels seem much better, and friends of ours charge batteries and run their refrigeration on theirs. However the overall cost does still seem quite high. My guesstimate is that an installed setup for our boat will cost in the region of 2,000 Euros.
We have an 8KW generator. It uses pretty close to a gallon an hour when under load. When living aboard we run it 45 mins a day to keep our freezer and refrigerator at temp, produce hot water and top up our batteries. If my sums are correct, we might get close to the price of a solar panel install if we live aboard full time for over 7 years.
bottom line: Solar Panels remain on the list, but there are other items higher up.
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By alshaheen - 21 Aug 2015
There is no easy or universal solution. A lot depends on where you are cruising, the type of sailing you are doing and the equipment you have on board, especially a freezer.
We found that in the Caribbean winter season we could easily exist with just an Airex wind charger for all our power needs; but they are noisy and anti-social in a crowded anchorage. In other areas where a good sustained wind is infrequent they are next to useless as a primary charging source.
On passage we use an Aquair towed generator which gives us 6 amps at 7 knots and that is sufficient for daily needs with a fridge but no freezer and LED lights, but obviously of no benefit when not sailing. Having wind vane steering cuts out the power requirement of an autopilot on longer passages.
Solar panels are attractive, if expensive, but the biggest problem is where to locate them where they are not in the way, not vulnerable and not in the shadow of sails, etc. Yes you can mount them on the guardrails on hinges but they are very vulnerable there when in a seaway and I have a personal dislike of gantries above the cockpit with all sorts of clutter up there. So, where to put them?
John
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By Dick - 21 Aug 2015
Hi John,
I agree with your comments about solar and wind for generating power.
Finding real estate for solar on a monohull is particularly hard if you rule out lifelines as I do (for offshore boats I believe nothing should be attached to something as important and vulnerable as lifelines including jerry cans but especially kayaks etc.). A well done arch can work, but is pretty pricey and often leaves one tempted to then have (and use underway) davits with a dinghy hanging there, often with a motor attached. A wind generator can be loud, especially if it is doing its job, but then, many think a genset makes for a pretty poor neighbour. At least one chooses when to run the GS.
Which returns me to: if you feel the need for a genset (big freezer or aircon at anchor), then forgo the passive power generation and its complications, put the weight in extra batteries and run the GS regularly and hard.
Dick Stevenson, s/v Alchemy
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By Dick - 21 Aug 2015
Hi Alex,
With respect to your wish to be greener, I fully support that inclination as long as we are agreed that there are few people greener in the western world than those who live aboard modest sized sailboats. Yes, solar has gotten much better as have the black boxes that control them. Rather than solar on your wish list and since you have a genset already, I would put your efforts into impeccable care and feeding of the beast, good spare parts inventory even if expensive and a larger battery bank (which can always be charged by the propulsion engine in a complete GS breakdown. If you wish to be further adventurous, I believe the new generation of lithium batteries will provide some impressive benefits to onboard off grid life (may be there already).
My best, Dick Stevenson, s/v Alchemy
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