What’s New In Alternative Energy?

Mid Atlantic repairs - changing a delaminating solar panel that was shorting to the deck.

Mid Atlantic repairs – changing a delaminating solar panel that was shorting to the deck.

It’s Boat Show time in Europe at the moment, with Southampton in the UK and La Rochelle in France packing them in to see what’s new in the world of sailing.

Being in the market for some new solar panels and wanting to catch up on the latest developments in alternative energy production, we made the pilgrimage down to the Solent and joined the crowd for a day. And we found that there were some interesting new developments on display that certainly justified our journey.

Fuel Cells

I’ve been watching the development of these units for some time, but have been skeptical about their benefits for a number of reasons. Early units were very expensive in relation to their output, didn’t like operating when the boat was heeled, used costly fuel that was hard to find, and there were widely expressed doubts about the longevity of the core energy generating ‘stack’. I mentally filed them under “to review” until such time as these central issues had been addressed—or not—and I have to say it does look as though they have been for the most part.

The helpful team from Fuel Cell Systems talked me through the latest versions of the German made EFOY range and I came away impressed.

Basically, a fuel cell generates power via a chemical reaction involving hydrogen and doesn’t produce any toxic emissions. In the case of these marine units, liquid methanol is used as the fuel as it is hydrogen-rich and easy to handle. In operation they’re quiet at 25dB(A) and produce only a small amount of water as a waste product.

Will fuel cells become a common sight on yachts in the future?

Will fuel cells become a common sight on yachts in the future?

Three models are available with different outputs, ranging from 80 to 210Ah per day. All share a common sized casing and weigh between 7-8.2kg (15.4-18lbs), plus fuel. Each unit comes with a mounting kit consisting of a base plate and retaining strap, plus exhaust hose, operating panel, heat ducting and wiring.

The minimum amount of space required for the fuel cell plus associated fuel canister isn’t huge, certainly no more than a small diesel generator, so it would fit well inside a (dry) cockpit locker, as long as it had adequate ventilation to allow the fuel cell to operate efficiently and dissipate the small amount of heat generated.

The EFOY fuel cell acts as a 12V DC battery charger, and the control unit simply senses when battery voltage drops below a certain level (normally 12.3V), and directs the unit to charge the batteries. When the batteries are charged the unit switches back to stand-by. It’s compatible with other alternative power sources such as wind or solar, and would in my view work well as part of an integrated system. No maintenance is required. It’s a simple, quiet, and apparently reliable device.

What of my original concerns?


Well, fuel cells are still not cheap: between £2,364 ($3814US) for the 80 to just under £5,000 ($8061US) for the 210, and you’d need to budget for at least a day’s work to install the unit, although anyone reasonably competent could certainly install one themselves.


EFOY insist you use their very pure methanol (they believe less pure grades will damage the unit) at around £30/$48US  for 5l/1.3US gallons. One liter of methanol will produce around 1kWh (~80 amp/hour at 12 volts) of power, so the cost/output ratio is acceptable. And it does mean, of course, that you’ve got to find space for and carry that fuel—no big deal for short voyages, but for longer ones to remote places that could be a problem.

Update April 2020: John here: Member Robert just pointed out that methanol is a potent poison, but worse still the vapours are heaver than air and so can pool in the bilge posing an explosion risk. To me, the latter would disqualify EFOY for use on a yacht.
Heel Angle

Manufacturing improvements mean that they can now operate at an angle of 35 degrees continuously and 45 degrees for up to 10 minutes (and who’d be worrying about battery charging at those angles!).


EFOY obviously have confidence in their product, as they offer a standard two year warranty for the smaller units, which can be upgraded to five years at reasonable cost, whilst the 210 comes with five years warranty as standard. And whilst it used to be said that the lifespan of the stack was around 5000 operating hours, reports suggest that many have already exceeded that figure considerably.

Another point to remember is that, unless your boat’s power consumption is very low, it might be best to go for one of the bigger units, which would run for less time to meet your daily needs. One of the smaller units would be running almost constantly to keep up with high demands, and so reach the end of its useful life far sooner.

Fuel Availability

One fly in the ointment remains the availability of fuel on a global basis, although Europe is now well covered. There are dealers on both US coasts and a few Caribbean islands, but much of the rest of the world is still without stockists. It is clear that EFOY are trying to spread their coverage though, which will be essential if they are to capture more business in the long-distance cruising market.


But for boats cruising in waters closer to home, for more ‘holiday’ based cruisers, or for an Atlantic crossing, I think there’s a lot going for them. Equally, one would be ideal for a smaller cruiser where the space required and the weight penalty would make a genset unattractive, or simply as a back-up if you’re that well off financially.

As with all supplementary energy generating systems, it all depends on your needs, but I can see a growing market for these attractive units, especially if they become more cost-effective, and the support network continues to expand.

Solar Panels

After the demise of our deck mounted Sunware solar panels (died from delamination after only five years) we’ve been looking around for a suitable replacement. Obviously we’d like to get more bangs per buck, but have been somewhat limited by the space available and the fact that we have to use semi-flexible panels (as before) that can accept being stepped on, so we weren’t sure that would be possible.

But we think we may have cracked that after looking at the Solbian SP panels available in the UK from Barden. These mono-crystalline panels use the latest SunPower back-contact technology to achieve a conversion efficiency in excess of 22.5%, which is really impressive, and should allow us to replace each of our 45W panels with ones of 100W for just a fractionally larger footprint.

Naturally, after our original disappointment we looked very carefully at the standard of construction, particularly the encapsulation, which is where our old panels failed. The Solbian panels appear to be much more heavily constructed, and the encapsulation is carried out well beyond the edge of the panel, and so should last far better.

The Solbian panels are very light (1.3Kg/2.9lbs) as they incorporate no metals in their construction. They also have an innovative range of options for mounting them, including a zip fastener so that the panels can be mounted securely on a bimini or an awning or removed for security reasons when the boat is unattended—nice idea.

All of this comes at a price, though, £792/$1278US for a 100W panel. But given that we could end up with over twice the output from the same area on deck, we think that may well be a price worth paying. As long as they last this time…

Like what you just read? Get lots more:

Meet the Author

Colin Speedie

Colin, European Correspondent here at AAC, is a deeply experienced offshore sailor who holds a Yachtmaster licence, and a gifted photographer and talented writer who has added a whole new dimension to Attainable Adventure Cruising. In addition, since Colin and Louise are from England and had their OVNI 435, Pèlerin built in France, they bring a European perspective to our site. You can read more about Colin and Louise and their business at their website.

48 comments… add one
  • John Rushworth Sep 28, 2013, 8:02 am

    I have to say I came to similar conclusions re Efoy and Hydro Generators. Bang for buck they are out of my price league too. My aims will be to get the re-gen braking on my eelctric drive providing a little addition, once I’ve changed the prop and programmmed the conttroller over winter. Solar is next then wind. However for solar I have spent a lot of time looking for a 24 Volt panel that raises and maintains a high voltage (and allowing for some shading). All in conjuction with an MPPT controller. I favour the Victron controllers and the Sunware 24Volt 80 cell panels, which have either top or bottom entry sealed cables.

    • Colin Speedie Sep 28, 2013, 10:10 am

      Hi John

      Your systems are way beyond the need for fuel cells or hydrogenation, but as I’ve outlined, for some boats (at least) they still have potential.

      I’m intrigued by your solar plans and hope you’ll update us on their progress at some stage – you’re breaking much new ground and that’s always interesting to hear about.

      Best wishes


      • John Rushworth Sep 28, 2013, 1:43 pm

        Hi Colin,

        Will do. This season and sailing locally (600 miles) I’ve proved my direct electric drive. A prop change to 3 blade and higher pitch is going to be good and give less RPM for better efficiency/thrust.

        Then solar is a must but some makes of panels/controller will drop out as they don’t maintain a high enough voltage. Especially when used to charge batteries with higher voltage rates like AGM. So a good charge controller to prevent low volatage disconnect seems wise.

        Also as I understand it shading is also a concern on a sailboat which again with less cells means less volatge. This is the reason I’m looking at 24V 80 cell as opposed to 72 Cell. Also the form factor is more square in shape and will suit my smaller boat. I think I’m going the right way and the fact that Steve Dashew said to me he is looking at higher voltage cells too suggests I may be on the right track.

        As I can only afford to fit one panel I’ll also use an Ultra fast MPPT which helps even more in cloudy conditions.

        • Jean-Claude GUILLOT Oct 1, 2013, 1:26 am

          I’m using around New Caledonia 3 flexible solar panels of 60W each on an aft arch with a Victron 70/15 MMPT regulator.
          When anchored my domestic 12V daily drain is totally recharged with batteries to 100% around 1PM.
          When sailing, with domestic devices working (fridge, radio, lights) as well as navigation devices (Raymarine depth, speed, wind, GPS, autopilot and VHF) the solar panels are still slightly charging, which means I’m autonomous for daily navigations (night at anchor).
          The maximum charging current I’ve observed until now is 8.5A (with a battery bank of 2 12V*100AH) and I feel the Victron 70/15 regulator is a pure wonder.
          Jean-Claude – SV Bauhinia

          • Colin Speedie Oct 1, 2013, 5:53 am

            Hi John and Jean-Claude

            Thanks for the additional information on the panels and particularly the Victron regulator. It does seem that the latest generation of ultra fast MPPT controllers offer real advantages in terms of coping not just with cloudy conditions but the inevitable shading that occurs on yachts.

            Best wishes


  • paul shard Sep 28, 2013, 9:21 am

    Hi Colin,
    Thanks for the Southampton Update!

    As you are mounting the panels on your deck I presume there may be issues with shading… are these panels tolerant to shade at all?

    Fair Winds


    • Colin Speedie Sep 28, 2013, 10:14 am

      Hi Paul

      There are issues with shading – but it’s the only substantially clear piece of deck we have!

      In practice they outperformed our expectations, and we miss them. Given the virtual cats cradle of sheets, shrouds halyards etc on a yacht it’s virtually impossible to avoid some shading. But with a little effort it’s possible to move lazy lines away from interfering with the panels, and where they are on deck you’re well away from the guardwires etc. In practice it is also true that it’s usually one panel that’s affected – one is usually in clear light.

      Best wishes


      • paul shard Sep 28, 2013, 11:29 am

        It will be the same on Distant Shores – the best space we have is under the boom on the cabin top. But these panels you have found are amazingly light and look like a great option!



      • Matt Marsh Sep 29, 2013, 11:23 am

        Colin, I’m glad you like the SunPower cells. Their A300 was becoming the de facto standard on solar race cars when I left that field in ’07; they outperform just about any other silicon cell on every performance metric. If you can’t do the job with these, you’d better be prepared for the sticker shock of space-grade triple junction GaAs cells.

        I’m not familiar with Solbian’s encapsulation system. It appears to be in a similar class to the SunKat system, which I am familiar with. (Very light, very thin, slightly flexible, still possible to break a cell if you bend them too hard or drop something heavy on them.) As far as I know, the gold standard here is still the (obscenely expensive) Gochermann flexible encapsulation method, which is so strong that even when you break a cell, the encapsulation holds the shards together tightly enough to maintain electrical continuity. There is a definite need for affordable competitors in that market.

        • John Rushworth Sep 29, 2013, 12:37 pm

          Just how expensive are http://www.gochermann.com/ panels? I can only fit something up to the size of a 70 Watt panel to my small yacht. So far the best for my application are an 80 cell 24 Volt single panel. Can you comment on them? Efficiency? Benefits of higher voltage?

          • Matt Sep 30, 2013, 9:12 am

            You’d have to contact Gochermann directly for current pricing, it’s been a few years since I looked into it. It used to be that all their stuff was custom (no pre-stocked modules) and when your main customers are solar cars, satellite manufacturers, experimental aircraft, etc. you can set your prices on the high side.

            Ideally, the optimal operating voltage of your panels (V_Pmax, not V_OC) should be roughly the same as your batteries’ charging voltage. The MPPT regulator will take care of any mismatch. If you’re omitting the MPPT and are using a cheap conventional regulator, a slightly higher panel voltage is preferable.

        • Colin Speedie Sep 30, 2013, 7:43 am

          Hi Matt

          The SunPower cells do look great, and it’s good to see them achieving greater market penetration in an area that benefits yachts.

          The Solbian panel I was shown looked to be of good quality – they claim that they employ a unique polymer for encapsulation ‘that allows for flexibility and significant weight reduction’ – no mention of durability, but it was thicker and more supple than on other panels I’ve looked at.

          Their spec sheets also suggest that the panels can accept 25% of bending which is also more than others I’ve looked at.

          But I’d endorse your comment of dropping stuff on them, no matter how well made they are!

          Best wishes


          • John Rushworth Sep 30, 2013, 10:10 am

            Hi Matt,

            Yes, I’d understood the difference between open circuit voltage and max voltage and to be above system voltage. My question was more what you thought of the more cells/higher voltage issue as I assume this takes/helps in temp variation voltage ouput from the standard 25 deg C and also stops voltage drop due to shading by going to 80 cell rather than 72 cell in a 24V sytstem. Also it seems to me I should be using a high quality MPPT charger that take shigher volatges as opposed to a less efficienct PWM, to be sure in the scenario above I don’t get low voltage load disconnects as my AGMs use a higher voltage charging regime than normal, which in this case would mean I’d always be charging at and above system voltage, no matter what the conditions. Also it would be a more disciplined charging alogorithm. I just have no experience of 24V modules with the extra cells to normal and wondered if you or Colin had any experience of them. I take your point about Gochermann and will find out more from them via a solar/electric boat guy I know who has used them at 22% efficiency to drive a quadracycle with the panel weighing less than 1 Kg. Maybe I’m in for a price shock! As I only have room to fit one panel I need to maximise area/weight/energy output in the smallest module profile by going for a single 24V rather than using two 12 V panels. When I’ve saved the money I’ll let you know how it works out. It might be awhile from what you say! Thanks.

          • Matt Marsh Oct 1, 2013, 10:42 pm

            John R.,
            My experience is that, with a good MPPT, the panel voltage doesn’t really matter. You’ll lose some efficiency if you ask the MPPT to “buck” a 28 volt panel down to 14, or “boost” from 14 volts to 28, but good controllers really don’t care about a small voltage mismatch. (The last solar car I worked on had array strings that were nominally around 120 V, feeding into a bus that could run anywhere from 90 to 130 V.)

            If you’re using cheaper regulators, then yes, there might be some advantage to be gained with slightly higher voltage panels in situations where the cheap regulator would otherwise cut out and scream “undervoltage”. And you’ll always have lower I^2 * R losses in the wiring with a higher voltage panel.

          • Eric Klem Oct 2, 2013, 9:32 am

            John R,

            My experience is very similar to Matt’s that the MPPT can handle small voltage mismatches with a negligible loss in efficiency. The trick with all of this is that it is specific to exact design and so it is hard to generalize and state what the best way to go is. Generally, it takes too much hard to get data and modeling time for people to really figure out what is the best combination of available components unless you really need that efficiency for something like a spacecraft or a solar car. I would try to match the typical panel output voltage as closely to the charging voltage of the batteries you are using.

            I would think that you would get much more benefit for your time and effort to develop a good tracking, shadeless system over trying to model exactly which components will match the best. I never cease to be amazed at how many boats have huge numbers of panels on them and all sorts of stuff mounted above like radar and wind generators.

            Something else which is not discussed very much but can give you a small boost in efficiency is to concentrate the solar energy. Putting a properly reflective material in the right place can boost your output and it is much less sensitive to shading. When I used to compete at tour de sol, we had a cheap, home-made reflector that was ~2/3 the size of our array and we could boost output by 10%+. Just be sure that you are not heating the panels unnecessarily. The advantage of this is that it is cheap and much less sensitive to the mounting considerations of the panel.


          • John Rushworth Oct 2, 2013, 1:22 pm


            Many thanks for all your input, for this, my first foray into solar.

            It is clear that there are many solutions for different sailing profiles and boat design. Mine as you may have gathered is one of space and cost. I am now leaning toward the Sunpower cells rather than the 80 cell/24V single panel Sunware solution, which whilst it seems well encapuslated, semi flexible and would help with shading on the coach roof – it is not so efficienct and very expensive and polycrystalline.

            Having done some more research it appears that the efficiency of the Solbian/Barden ones Colin mentions of around 22% are in fact using Sunpower cells in their modules.

            As I use a 24V battery string I prefer to use one panel rather than 2 x 12 Volt panels for efficiency and space saving. That restricts my off the shelf choice.

            I think in that case I shall start with 1 only of these panels below on the stern of my small double ender yacht. (Clever Solar)

            Whilst a heavier and rigid glass type panel and not a truly marine designed panel I think the price and the efficiency (21.5%) are good. Sunpower cells. At £420 inc VAT for a 135W 24V monocrystalline panel it seems OK, albeit heavier than the Solbianones Colin found.

            I could possibly add another semi flexible 24V panel on the coachroof at a later date. Coupling that with an Ultra Fast MPPT which needs +5V over battery voltage to start it, then as I like Victron products, this charger would seem a good choice.

            Coupling a stern mounted panel with an adjustable mount as Eric suggests and staying away from boom shading – then for those longer coastal tacks – I would expect to harvest around 500-800 Watts a day in the Summer in Scotland. That would drive my electric propulsion at between 3 to 4 knots for 1 hour and take care of my house loads of around 30 Watts.

            My boat lives on a mooring inbetween day and weekend sailing with the odd week or two away. In that case it will recharge my propulsion bank in around 7/10 days from 50% discharge, which all saves me the £20/visit to a marina. The payback time may be awhile but anything that helps is good – and I do like the silent ‘free’ solar contribution. Maybe a small wind genny later. The regenerative braking function of my propulsion motor (when I’ve changed the prop) may give me around 5 to 10 Amps @ 24V when sailing close to hull speed of around 6 knots. We shall see.

            Out of interest, I have done just 600 miles this season with the electric motor. Not much compared to the dedicated full time crusiers I know. However my total energy consumption for propulsion inc houseloads and a bit of heating has been 100kWh.

            Domestic electricty in UK is about 15p/unit, maybe 20p in a marina. So that is a total of around £15 to £20 for 600 miles of travel. Beat that with your diesel 😉

            Open to any flaws in my thinking? Remember Matt has the advantage of a good fast brain on young shoulders but mine has slowed down with age, so things take me at least twice as long to figure out! My exscuse anyway. Thanks.

  • John Sep 28, 2013, 9:36 am

    Hi Colin,

    A great update, thank you. The advances in solar are making me think that alternative energy may finally be getting to the point that it can make a realistic dent our energy requirements on “Morgan’s Cloud”.

    One other question. The makers of these fuel cells are claiming to be super-green, but I’m confused about one thing: Since they are using methanol and the formula for that fuel is CH3OH, wouldn’t one of the byproducts be CO2? After all the carbon must go somewhere. Or do they capture it in some way. I took a look at EFOY site, but did not see an answer.

    • Colin Speedie Sep 28, 2013, 10:20 am

      Hi John

      Existing fuel cells are generally accepted as being efficient and pretty clean. EFOY (www.efoy-comfort.com/how-it-works) suggest that the only waste products are a little heat, water vapour and very low amounts of CO2.

      And there are some really interesting developments in the pipeline that may enable waste CO2 to be converted from power stations etc. for use in fuel cells. An example of this type of innovation can be seen at http://www.sciencedaily.com/releases/2012/06/120613132937.htm – so I think there is still plenty to come.

      Best wishes


      • John Sep 28, 2013, 10:36 am

        Hi Colin,

        Thanks for the explanation and the interesting link. Has anyone done a study of the greenhouse gas emissions of fuel cells against a diesel generator on a per kwH basis. I assume that it would be a big win for fuel cells, but it would be interesting to know how big? But then I guess to be really accurate you would have to compare the carbon footprint of manufacturing (refining) the two fuels. Yikes, my head hurts!

        • Colin Speedie Sep 28, 2013, 10:53 am

          Hi John

          I’d say that fuel cell would win handsomely, on that measurement at least. Another are that fuel cells have an edge would be in conversion efficiency of fuel (20% of chemical energy conversion in a gasoline engine, 60% conversion in a fuel cell). Granted that there are differences in the value of the fuels, that’s still highly efficient.

          And despite the fact that fuel cells have been around a long time (since the 1890’s at least) there does seem to have been a resurgence of interest in recent years and it’s clear that there are more benefits to come.

          But you’re quite right. All aspects from production to disposal do have to be taken into account – and it makes my head hurt, too!

          Best wishes


  • paul shard Sep 28, 2013, 11:51 am

    Hi Colin,

    I am wondering about the efficiency claims for the fuel cell.

    You mention the unit produces 1kWh for 1 liter of this methanol…

    Our small 3.5 Mastervolt genset uses about 0.7l/hour at around 1500 watts (pumping in 100-120Amps or so to the battery bank at 12V). At $1.50/Litre that means I spend roughly $1/hour and get 1.5kWh versus about $10 for 1kWh for the fuel cell…

    Also possibly I have this all mixed up since I also am getting a headache 🙂


    • Colin Speedie Sep 28, 2013, 12:47 pm

      Hi Paul

      No, I think your numbers are probably correct. And it’s one of the reasons that I think fuel cells will have a limited appeal, as I’ve suggested. For a small boat, for racing boats where weight is an issue, or for someone who wants no maintenance I can see the appeal.

      Or, as I also mentioned as part of a solar/wind/fuel cell package for an owner committed to a low carbon footprint.

      Of course it’s also worth factoring in the cost of servicing, ancillaries installation of the genset vs. the fuel cell, but the numbers are still substantially in favour of the genset.

      Best wishes


    • Matt Marsh Sep 29, 2013, 11:06 am

      Methanol’s energy density is 19.7 MJ/L, or 5.47 kWh/L. So, if we’re getting 1 kWh out of the fuel cell for every 1 L of methanol we put in, the cell’s running at about 18% net efficiency.

      That’s not too bad for a direct methanol proton exchange membrane cell, but it does suggest that the methanol cross-over kinetics remain an unsolved problem. (Previous direct methanol cells have had issues with up to half the methanol diffusing through the membrane and reacting on the cathode side.)

      I think the appeal here will be that the fuel cell is silent and produces no smell. Those are pretty big points in favour when comparing to a diesel genset. The manufacturer will, however, have to get it running reliably on less refined grades of methanol (ideally the $2 a litre stuff used by race cars, rather than the $10 a litre stuff used in the lab) for it to make a real splash in the market.

      • Colin Speedie Sep 30, 2013, 7:32 am

        Hi Matt

        Thanks for the analysis on the fuel side.

        Like you I think that there are benefits beyond the obvious with fuel cells, not least in terms of being easy to live with, and I’d hope that the improvements that I’ve seen since I’ve been watching them will continue, not least in terms of affordability.

        Best wishes


  • Gabriele Sep 28, 2013, 7:22 pm

    Hi john! Why buy solbian in uk when solbian solar are made in Italy?
    Call asseaboat Italian branch of solbian and talk with Gianpietro! Tell him that you speak with me the owner of folkboat marieholm n Italy and you will get a good price!
    Take care

  • Dick Stevenson Sep 29, 2013, 5:23 am

    Colin, Thanks for the report. I have been watching those fuel cells out of the corner of my eye for years and am pleased they are making the progress you report. Next, I look forward to actually field reports. I am not sure about others, but the longer I am wandering about on a boat, the more I am willing to pay a premium for no/little maintenance and no-brainer attributes. My DC genset (little Kubota tractor diesel coupled with a big alternator) has done its job, but was/is a continual challenge to varying degrees. And this season with so many marinas (Baltic) it has hardly had any use, another source of concern. My read on the fuel cells is that sitting un-used is not a problem for them. Correct?
    Thanks, Dick Stevenson, s/v Alchemy

    • Colin Speedie Sep 30, 2013, 7:54 am

      Hi Dick

      There are some interesting field reports on their website, especially where they’ve been used on high tech race boats like mini-transat boats, where they’d get shaken up, for sure!

      My understanding is that they are fit and forget items. The controller comes with basic factory settings covering on/off voltages (which can be fine tuned) and beyond. They quote an operating temperature of -20C to +40C, although start-up temperature and storage values are more restricted. And they do offer a guarantee of five years on the biggest unit (the one to have in my view), which is always a good sign.

      Best wishes


  • richard s. Sep 30, 2013, 8:23 am

    the last i knew…seems like just a few weeks ago… you were in the brazil area colin…now back in the u.k. apparently…did you return by air? guess i somehow missed all this

    f y i, just purchased a 20 watt (1.5 amp) polycrystalline panel by wel-bilt on sale at northern tool and equipment (similar to tractor suppy co.) for $60 tipping the scale at 6 lbs with aluminum framing and a 10-year warranty so i am thinking i found quite a bargain although the salesman, who seemed knowledgable, said the crystalline panel is more shadow sensitive than the amorphous, which i didn’t know…he said the trade-off is the crystalline packs more of a punch than the amorphous, which i think i already knew…haven’t installed it yet, but i look forward to not having to run the volvo as much, which i’m sure is humorous to larry pardey as he and linn don’t even have auxiliary power…my hat is off to them as this at least doubles the mental effort i would think in handling a passage maker


    richard s. in tampa bay (s/v lakota)

  • Colin Speedie Sep 30, 2013, 8:52 am

    Hi Richard

    We’ve been back in the UK for a little while now, but Pelerin is out on the hard in Trinidad, and we’ll return to her in November – can’t wait.

    The answer on the difference between the amorphous and polycrystalline panels is that poly are far more powerful if surface are of the panels is equal. Amorphous panels may have an advantage in lower light, but it depends on the manufacturer and whether they have built in low light efficiency tech into the panel or not. As always, you pays your money….

    I’d suggest that the panel you’ve bought will certainly help keep your batteries topped up when you’re not on board, but you’ll need to fit a substantially greater area to make an appreciable dent in your engine running hours – but it all helps.

    Best wishes


  • Erik de Jong Sep 30, 2013, 12:58 pm

    Hi Colin,

    Reading your article, i can’t help but wondering why shaft generators are not used anymore these days. We have a 110A/24V alternator driven by a belt on the prop shaft. While sailing at 6 knots, we get about a 1000W, sailing at 8 knots, it is as high as 2000W.
    Total investment was about $300 for a used truck alternator plus $150 for a pulley with double belt, and one day of work to install. It is maintenance free, and does not consume any fuel, takes practically no space and weighs maybe 8-10 kg’s.

    Total power generated will of course depend on the diameter and type of propeller under the boat, and it is necessary to have a gearbox that does not wear down while running freely, but if a boat has the option, it is the way to go if you ask me. In general, we only need to have it running about 1 hour a day to keep up with the electrical demand. Since we are generally sailing in the high latitudes, I’m considering installing a electrical heater in the boat that can be powered by the generator.

    Best regards,
    Erik de Jong

    • Colin Speedie Sep 30, 2013, 1:10 pm

      Hi Erik

      I think they’re still a great idea, and covered them in a previous post that now forms part of the ‘Staying in Charge’ eBook.

      French manufacturer Valeo now make a dedicated 25A unit that kicks in at very low revs, and Boreal have fitted one to their own boat, as well as clients.

      And I love the idea of generating heat from a large unit as you do – why not?

      Best wishes


  • Jean-Claude GUILLOT Sep 30, 2013, 8:12 pm

    Hydrogenerator : a Swiss company is now offering a cheaper alternative to Watt & Sea and Cristec hydrogenerators :

    Fuel cells : the German company TRUMA is proposing a new fuel cell, which uses propane as fuel.
    jcglt – S/V Bauhinia

    • Colin Speedie Oct 1, 2013, 6:00 am

      Hi Jean-Claude

      Thanks for flagging these units up. I had heard that there was another hydrogenerator coming to the market but hadn’t seen it until now.

      Interesting to see a fuel cell using a fuel that’s likely to be already aboard a cruising yacht, which should make life easier. It’s a big powerful unit, but the weight (at 40kg) might rule it out on smaller yachts where fuel cells look to have an opportunity over a generator.

      Best wishes


  • Dave Sep 30, 2013, 11:23 pm

    Thanks for the opinion on Solbian cells. I have been looking at them for installation in an aft framed canvas arrangement, where they’d be out of the sun. Looking at three SP100 panels.
    Always good info here.

    • Colin Speedie Oct 1, 2013, 6:02 am

      Hi Dave

      I think that they’d do really well in such an application, and I like the zip fastener idea for mounting them in such an application. Three 100W panels should really put out some power, saving a lot of engine hours.

      Best wishes


  • Mike Owens Oct 11, 2013, 10:01 pm

    Hi Colin,
    Great article and discussion.

    I have a query regarding the suggestion that for maximum efficiency when using MPPT controllers panels should be selected with an output voltage as close to the charging voltage of the batteries.

    If 12v rated panels are selected (e.g. with a Max power voltage of 15v and an open circuit voltage of 18.75v) for a 12v battery bank and an ultra-fast MPPT controller such as Victron is used which requires +5v above battery voltage (17v) to start the charging does this mean that in low light levels there is a possibility that the panel would not generate enough voltage to start the charging process?
    If this is the case it would suggest that a higher voltage panel e.g. 24v would be preferable.


  • Jean-Claude GUILLOT Oct 18, 2013, 8:38 pm

    Thorium laser generator : a new path to watch.
    Take a thorium laser heating a fluid, which feeds a steam turbine, which turns an alternator…
    A car company claims they will sell within ten years a car actuated by such a generator feeding electric engines of 350HP and that this car will need only EIGHT grams of thorium during its whole life.
    Such a generator burning less than ONE gram of thorium could feed in electric energy a boat during her whole life.t hope we’ll find such a generator on the market within ten or twenty years ?
    We can jus

  • Bryce Oct 30, 2014, 2:52 am

    We are intending to get some semi-flexible solar panels to affix to our soft bimini & dodger (2×150 watt). This will go with our existing 2 x 75 watt rigid panels, bringing total solar up to 450 watts. I’m coming up to speed with the technology, but I have a couple of queries that I’m hoping someone can help with:
    1) Is “ultra-fast” MPPT the same thing as MPPT?
    2) Is it better to have a single, larger MPPT controller for the bank (e.g. Morningstar Tristar MPPT 45), or a number of individual smaller controllers (e.g. 3x Morningstar Sunpower 15 MPPT)? In this example the larger unit has a higher efficiency (99% vs 97%).



  • Marc Dacey Oct 30, 2014, 3:11 pm

    Given the variables of cloud, shadow (boom or sail) and bird poop, I’m not sure I would quibble between 97 and 99%. I have four Kyocera 135W hard panels in an arch for the purpose of shedding water and getting a more productive angle on a typical heel, but I know if I don’t make amps from 1000-1400h, output will be irrelevant. I haven’t heard the term “ultrafast MPPT”, but my Outback FX 60 seems good at this stage. Personally, and only on the basis of experience, I would not bother with multiple MPPTs just because the wiring would get problematic and the setup overly complex for me.

    Having said all that, I’m changing my arch setup. Watch my blog for the results next spring.

  • geir ove Jan 26, 2018, 5:47 am

    here in Norway we had last summer 2 boats that got a short in there flex panels, and it started to burn. one had the german made the other the cheeper chines made. But they al look like it is getting to hot and it starts to make smoke and …
    Not good. i also know more boats , where the flex panels start afther just one season loos the topp prtectiv layer.
    So i will only use the glass/hard once.

    • John Jan 26, 2018, 10:00 am

      Hi Geir ove,

      I had no idea that was even a problem with flexible panels. I’m just looking at buying a couple of panels for our boat, so thanks for the timely warning.

  • geir ove Jan 26, 2018, 11:32 am

    Sendt you pictures of the one that startet to burn.

  • Frode Jun 29, 2018, 7:13 pm

    The potential longevity of the (semi-)flexible panels appear to be governed by the type of plastic used in the encapsulation process. The traditional, PET (Polyethylene terephthalate), appears to be easily damaged by UV, and to have diminished abrasion resistance. The newer, EFTE (Ethylene tetrafluoroethylene), promises to significantly improve on both of these, at least pushing the expected life span to more than 10 years.

    Only some of the manufacturers use EFTE. As Colin points out, the best cells are SunPower’s, specifically their Maxeon Gen III. Strangely, SunPower makes their own flexible panels, but not encapsulated with EFTE. I pointed out to them that as cruisers, our panels are in use 365 days per year, not just the odd weekends, as the camping and RV crowd might require.

    I’m buying replacement panels for my entire array from Lensun. Unfortunately, I have very little research to back up this choice, and the potential longevity of their panels will not be apparent for at least five years, so this should not be taken as a recommendation. Their price is roughly USD 2.65/watt (EUR 2.25) as of June 2018, for 100 watt panels.

    At this price level, it appears these panels are, if you have the space, the best option to add more power.

    • John Jun 30, 2018, 7:26 am

      Hi Frode,

      Thanks for taking the time to share that, definitely useful to know.

  • Robert Cornah Apr 28, 2020, 5:22 am

    There is another factor that does not seem to be mentioned in the discussion of methanol fuel cells. Methanol is extremely toxic – 10 ml ingested may cause blindness and 15 ml potentially death. It is also absorbed through the skin or by inhalation, and can cause severe toxicity by both routes. It can mix into water and remain undetectable but still toxic, and the vapor is highly flammable, toxic and heavier than air. The antidote is ethanol.

    Leakage into the bilges or similar could cause significant risk and be difficult to detect. I know it is used quite widely in cars, etc, but think it would need special precautions and care on a boat.

    • John Apr 28, 2020, 9:03 am

      Hi Robert,

      Wow, I knew that methanol was a potent poison, but I was not aware that the vapour is heavier than air. Really good to know, I will update the post to reflect that.

  • Mal L Aug 10, 2020, 10:26 am

    Hi Colin, i was very interested in the Cristec Hydrogen but couldn’t find it listed on the link in your story to ‘Advance Yacht Systems’.
    I did find this pdf https://www.marinea.fi/downloads/cristec_hydrogenerator.pdf and it looks a great unit! but I couldn’t find it in Cristecs website or catalogue, are you aware if Cristec have ceased production of their Hydrogenerator?

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