I received this comment recently on a mailing list...
"Our experience over the years in the Caribbean is that solar panels work but only on boats which have minimal electrical requirements. Even the sailboats are running their engines to keep the refrigeration and freezer going once or twice a day. We had solar & wind on our sailboats so we do have lots of first hand experience with both.
We encounter sailboats with 4-6 panels and two wind generators who still run the diesel daily. That's a lot of space devoted to panels and a lot of noise 24/7 from the props."
So I'm looking for some real world experience with powering a boat's systems with solar & wind.
I'm planning on a little over 100 amps per day and was expecting to get most of that from 2 large panels and a wind gen. Not practical?
We find solar panels are rather over rated. We have two 55 watt panels and they produce enough power to run the fridge as long as we get good sunny days. They have numerous weaknesses
a) ANY shade across the panels (shadow from mast, halyards, lazyjacklines, bird droppings, whatever) or cloud seriously reduces or even eliminates the output.
b) extra panels are heavy, expensive and they only work for about six hours a day IF it is sunny.
c) even suppliers have advised us that wattage on most panels is over rated. That is 120 watts of panel will never produce 10 amps on a 12 volt system - 8 if you are lucky and conditions are perfect.
We find with a freezer (cooled by water pump), hydraulic autopilot, lights and a laptop used for navigation and digital TV reception we use about 100 amp hours per day more than the solars produce. That means we have to run our 110 amp alternator for about 1+ hrs per day to maintain power, more if the solar panels have been limited by cloud etc.
Currently looking for a wind generator as more panels will still have same limitations but a wind generator will work whenever the wind is blowing. There seem to be two different styles. The three bladed feathering prop versions only kick in at about 12+ knots but produce more power when they are operating BUT they are incredibly noisy. The multi blade versions work at lower speeds, are silent, but produce less power for same wind speed. Typically four amps at about 15-17 knots.
Price seems to be equivalent to a single 110 watt panel. We are currently looking at a Rutland 913 made in the UK. Any one tried it?
Not sure if any of this helps but would love to hear what others have experienced.
I guess a lot of it has to do with what you're running on your boat, and the design and efficiency of the refrigeration. I have relatively modest electrical use on my boat—a small DC refrigerator, a stereo, a VHF, running lights, cabin lights, a laptop computer—and I find that solar power is more than adequate for my needs.
It also depends on how you plan and implement your solar panel installation. My two panels are setup so that one can be used with no shading whatsoever while at anchor.
A freezer, cooled by water pump, hydraulic autopilot, and satellite TV is going to draw a lot more power than I use on my boat.
As for wind generators, I am partial to the DuoGen units. They seem to be pretty well built and the added versatility of being able to use it as a water generator, means that additional electricity can be generated on long passages, without the need for running the engine.
__________________
Sailingdog Telstar 28
New England
You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.
—Cpt. Mal Reynolds, Serenity (edited)
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I guess a lot of it has to do with what you're running on your boat, and the design and efficiency of the refrigeration. I have relatively modest electrical use on my boat—a small DC refrigerator, a stereo, a VHF, running lights, cabin lights, a laptop computer—and I find that solar power is more than adequate for my needs. .
It's also a function of your battery capacity and your cruising style. I was having this debate with a friend of mine with a similar steel full keeler. He was thinking that when he upgraded his engine, he would run two 100 amp alternators to get a rapid charge on his battery banks. This is a man who likes his toys, mind you.
Our energy needs are more modest. While we have a 2000 watt inverter, I am going to simply get a bigger battery bank than most people (probably three 8D AGMs). I will charge this on the hook with solar and will carry a Honda 2000 gas generator for running power tools and if necessary to charge the banks. I figure that the key to not running the alternator to produce electricity (which I consider noisy and inefficient) is to have a modest energy budget in the first place (that means fridge, but not a lot else while stationary), and to seriously gear your stays to your passagemaking.
By this I mean that if you expect to be on the hook for a week in some tropical paradise, have enough capacity (with solar charging) to defer running the diesel until you decide to up anchor and go to the next place via *motorsailing*. Then you can run the diesel *under load* efficiently and get your charge on for much of a day, say, while blowing fumes, heat and noise in your wake. Then you can return, if you wish, and get a rep as "the quiet boat".
This is possible for us, of course, because of the nature of our boat and my actual desire to keep a half-ton of lead on either side of the engine room for ballast purposes. But it's not a crazy idea for many cruisers to carry more amp-hours that can give them more of an ability to burn diesel to turn an alternator.
Of course, along with energy budgeting (that plasma 42" LCD has no place aboard, does it?) is the idea of better or even extreme insulation, meal planning that doesn't rely on refrigerated foods, and just saying no to ice cubes that cost a buck a litre.
My own experience parallels Anlyns. On the last boat we had 160 watts of solar panels (Kyocera...Good product!) and a FourWinds wind generator used over several winters in the Bahamas.
On good days we would get aybe 40 amps out of the panels. The wind generator is capable of producing 4-6amps/hour in 10-15 knot winds which is around 100 amps in 24 hours BUT...you have to have at least that much wind to generate anything usable...and most people anchor in protected spots where wind and waves are reduced. I am not a fan of the little blade units for this reason as their output is even worse in modest winds.
Furthermore...I think most people underestimate their electrical usage when planning. As it gets hotter...your refrigeration runs a lot more, you use cabin fans more and there is just more stuff every year to spend amps on.
So...the net result was that we got an average of 100 amps or so a day out of our passive stuff and "spent" an average of 150amps a day in use which we made up when cruising to other anchorages or running the engine every few days since we had a big battery bank...4x4d's.
Obviously...you can get closer to "carbon neutral" by being more conservative in your use of stuff, doing without refrigeration etc. but I also found that the passive stuff did not do a good job of cycling the batteries and you DO need to get a good 3 stage charge on them at least once every couple of weeks to keep the sulfation down. We would run the batteries down to 50% and then go for a drive or pull into a dock for a night to accomplish this after we went through our first set of batteries in a year through a lack of understanding of both proper care and the need for good passive regulation.
Hope the above is helpful.
If you will give me just a bit longer, I will give you all first hand experience.
I purchased my stuff a while back, but have been dragging my feet on putting them on (as I do not want them to walk off the dock), but am about ready and everything is prepped. I bought 4 - KC130's, wired series, connected to an Outback MX60 MPPT. The wind is an AirX. THat should give me about 520 watts on solar, somewhere between 36-45 amps depending on voltage at max output. The MX60 MPPT is in theory able to convert even low levels of light into something that is useful (even if to float). The boat I fashioned after had 6 panels and not 4, but put out 65 amps/hour in the summer (an important distinction with panels). 6 panels is a bit tough for me to squeeze (space wise) so I went with 4.
I will try and get pictures and post them. Maybe I should shoot a shot of the charge controller so everyone knows I am not lying about what it puts out!!! HAHA!
I think the problem and negative comments associate with solar are associated with arrays that are too small, not using a MPPT charger, not using AGM's as batts (I will explain), and poor location. Unrealistic expectations might fall in there too.
As far as AGM's, (not bringing up an old thread), but for the life of me I do not know why anyone would not go with them (except cost)??!! THe only comparable wets are probably Rolls, but they are not cheap so why not a good AGM like a Lifline?? With an AGM, assuming voltage is regulated, you can really put in high current and faster recharges. THis makes them a better candidate for cruising with generators, mains (as a recharge source), and solar. Wind will be longer and more constant, so would be applicable to either battery type. Here is a post from Lifeline, which I use:
LIFELINE MARINE BATTERY BENEFITS
User Safe
sealed construction
non-spillable
install in any position if properly supported.
submersible without damage
Maintenance free (no adding water or repairing corroded terminals)
Fastest recharge. (no current limitations with voltage regulated recharging)
Deep Cycle (thick positive plates to provide real deep cycle performance)
Outstanding cranking performance (aircraft cell construction lowers internal resistance)
Best charge retention (especially against flooded cell types)
Lowest discharge rates (Less that 3 percent per month unattended)
Easily shipped (even via UPS except GPL-8D and GPLAD because of weight)
Shock and vibration resistant. (100% of plates are covered with separator liners)
Properly supported, LIFELINE AGM batteries with absorbed electrolyte can be installed and operated on their side.
I also use 4 - 4D's plus an alternate starter battery totally seperated from any of these systems as a backup/emergency starter. I also have a generator and use a Prosine Inverter/Charger 2.0 (I really like it).
I agree with Cam's point about a good MS charge.
My array is smaller than the boat I fashioned after, so the real test is coming very soon. We will see and I will let you know if I can arcweld in full sunlight!!
Take care.
- CD
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If your going to use solar to charge your batterys, I don't think you should use AGM's. Goft cart batterys would be far more "forgiving" if you don't get the full charge into your batterys from the solar panels. Goft cart batterys would also allow you to dip down to a 50% charge, 100's of times more then an AGM. You could also buy 2 goft cart batterys for the price of 1 AGM and have more amps also. My 2 cents.....
My lifeline AGMS sat in my dockbox (infreezing and sub freezing temps) for 3-4 months. I pulled them out and hooked them up to the Prosine. They were fully charged in about an hour or two. They only lost a very, very small % of their charge and accepted the charge very quickly. Versus my experience with wets, those POS would still be trying to charge up and would have been seriously depleted.
I am not changing the subject on Solars and wind efficency, I am merely pointing out that it is a piece of an entire system that works together. I will try and put some thoughts into writing up something more detailed and complex, but will likely need Hello's & Dave.Verry's help as there are pieces of electrical planning and engineering that get a bit confusing to me (and they seem to know their stuff).
- CD
__________________ Sailnet's best looking and smartest EX-Moderator!!!!
So...the net result was that we got an average of 100 amps or so a day out of our passive stuff and "spent" an average of 150amps a day in use which we made up when cruising to other anchorages or running the engine every few days since we had a big battery bank...4x4d's.
Hope the above is helpful.
Sounds about like what I'm planning. With an 800 amp battery bank, I figure I'll have the 400 to 700 amp range to use. That's 300 amps. If I'm short by 50 amps per day (100 supplied & 150 used) then I'll have aprox 6 days before reaching 50%. I can deal with that, no problem.
Cam, thanks for some real world data.
Xort...sounds about right.
CD...you found room for 520 watts on a 40 footer?? Are you building a pilot house out of them?? Send pix when you're done. I will be most interested in seeing your results in use as well. Will stay tuned! BTW...I agree with you on the AGM's...they are QUITE forgiving and lose less charge and charge faster than any other type. Many people confuse them with Gels which are a whole different ballgame. Of course the price differential is massive between wet and AGM which is why I started out with flooded...but I've learned my lesson.
