View Full Version : Wind or Solar powered charger ?
01-08-2003, 02:05 PM
I was thinking it would be a neat idea to set up a wind or solar powered battery charger to my boat. She has 24 volt electrics supplied by two groups of 2x 12v batteries. Reasons behind the thinking were 1) So I can run the (large) fridge etc when anchored out of port for days at a time 2) So I can leave the batteries on a constant trickle charge over the winter which will insure that the auto bilge pumo always works if needed and that the batteries (I hope) should have a longer life.
Is this feasible and would solar be more effective than wind, seeing as Aquarius is moored in the South of France ??
01-08-2003, 02:21 PM
Why have just one?
I take it you have the manuals to tell you how many square feet of panel you'll need to keep up with your requirements and how much wind. Especially with refrigeration, you may well need both.
I'm inclined to both; if there are clouds it's more likely to be windy, and vice-versa.
01-09-2003, 12:30 AM
You're going to need some array of panels for refrigeration, unless some major break through has been made in panel output in the last year. I'm not crazy about big props swinging around near people's heads either. I know of one person that was killed by a wind powered generator, though I've used the setup before.
I've been playing with this idea I've had clunking about in my head for a few years. It all started when I had a chain saw bite the big one and didn't toss out the carcass when I got the replacement. I stripped the still working engine of all it's unnecessary parts (bar, chain, oiler, handle, etc.) and mounted it on a chunk of 2 x 12 PT. I put a V belt pulley on the shaft and made a bracket for an automotive alternator and mounted it next to the motor.
The idea was to have a very fuel sipping engine drive my charging and electrical needs when off shore, without the fuel and vibration costs of a real gen set. I was able to muffle down the engine to a whisper, at great cost to the engine output I'm sure, but found it could handle the fully loaded 90 amp alternator with partial throttle.
I did have cooling problems that could be easily fixed. It needs to be self starting and regulating. Both of these issues seem easy enough to solve, but I haven't fooled with it for a while.
Picture this: you run four batteries in two banks of two. One bank drives the electrical needs until they have discharged enough to warrant topping, where the regulator setup would switch banks, start up the engine and charge the dry bank, before shutting itself down. I've seen self starting engines on model airplane engines and the very little bit of fuel, noise and vibration when compared to a typical gen set make this seem a way to go.
01-09-2003, 01:36 PM
A solar panel would be great for trickle charging in the winter. On the other hand, to keep a refrigerator running for any length of time would take a LOT of solar panels. A wind generator will produce a lot more power than solar panels, and might be able to keep a refridgerator going, but I don't think that I'd want to leave one running for extended periods when nobody was onboard the boat, as in during the winter.
In either case, what you really need to do to go very far with this is sit down and work up an energy budget for the boat. Figure out how much power you need under various circumstances (winter, summer at the dock, summer on an extended cruise). Then figure out how much power you could expect to get from various sources, factor in how long you might have to go without input (cloudy days or windless days) and see how things add up. If your boat is at a dock in the winter, and so at a fixed angle to the sun, you could increase the power produced by the solar panels by quite a bit if you tilted them south to face the low winter sun. Various books (I can't think of any titles off the top of my head) will help you with figuring out how much power you could actually expect over time with a wind generator or a solar panel.
01-09-2003, 01:47 PM
That's an interesting idea. A question: If genset motors don't have to be so powerful, why are they?
Also. I've never been around wind generators, but have heard that some can make an awful racket, especially the early ones. How noisy are the better ones?
01-09-2003, 01:58 PM
Rather than trying to provide energy requirements to keep a refrigerator running, you might be better off going with a propane powered refrigerator and a smaller electrical set-up just big enough to power your lights and electronics.
01-09-2003, 02:29 PM
My quarter century wind mill is acceptably quiet and I've heard newer ones that hum loudly. In general, the bigger and slower turning the blade, the quieter it will be, but there are trade offs in space. Depending on your regulator and on the windmill, you may be able to deploy and ignore in all but the highest winds. I preferr to turn it on and off myself.
I don't know if Pacific Turbine still exists. They made the only solid absorbtion refrigerator I know of. You want to avoid normal amonia units as they easily air lock, even if gimbaled.
I'd personally NEVER have an untended, essentially untendable, propane fire going. Too easy to go boom in the dark. If you must go absorbtion, have a drip feed diesel heat sourse that's got good overflow shut off.
Another approach that is cost effective is to have nice plates - like hold 'blue ice' - and cool them off with an occasional spritz of dry ice from a CO2 bottle with gauze. That at least keeps your regular box fully in tact and makes an ice box atmosphere that will discorage nasties. If you boat's properly vented, the little bilge accumulation that will go down the ice box drain tube will not be a problem.
I once costed out varioius refrigeration systems I could buy and install myself. I figured if I could find one that ran on no fuel at all with no maintenance needs for more than 5 years, it would become as cost-effective as buying ice. And I don't even do that every day - or even half the year.
As some off shore type noted, everything that really needs refrigeration - red meat etc - is hard to digest off-shore anyway.
Further, everything breaks at least once a year and one thus should have less than 365 things if one wants to have any days of repair-free sailing.
Thaddeus J. Van Gilder
01-09-2003, 02:50 PM
last summer I kept a heavily salted slab of bacon in my locker, and all I did when I wanted some for breakfast was slice off some and soak it in freah water over night, changing the water a few times before I went to sleep. It was also smoked heavily, which also probably helped keep it good as well.
Just a thought.
I do keep a little igloo to keep the beer cold in, but I am installing a wood keg from these guys
http://www.lehmans.com/cgi-bin/ncommerce3/CategoryDisplay?cgmenbr=12426&cgrfnbr=263566&FROM_CAT_REF=263563to have rum on tap at my sink. This will be kept wet to keep it cool..
[ 01-09-2003, 02:51 PM: Message edited by: Thaddeus J. Van Gilder ]
01-09-2003, 04:53 PM
Wind machines work well, but they need plenty of breeze to really give many amps-there is lots of info available on this from the cruising forums, SSCA etc-lots of opinions on which are best, quietest etc-Four Winds, KISS, Air X etc-like all things, there are compromises, but if you look around any anchorgae with offshore cruising boats you'll see lots of wind machines and lots of solar panels (and lots of opinions to match)-cuz they work and the sun and wind are free! Short answer-sunny area, light breezes-solar is the only way to go, breezy area-wind machine, a bit of both-well, a bit of both. If you are leaving the boat for a long periods, you'd probably want solar with a regulator, most of the wind machines have upper wind limits which would be enforced by self destruction if no one is around to tend it...
01-10-2003, 01:28 AM
I've found most gen sets to be much bigger then the boats electrical needs warrant, but capable of running damn near everything on the boat plugged in and running at the same time. Nothing but a small floating condo should need 5000 kW gen sets. The diesel is the other problem, vibration and noise specifically.
There is a sterling engine gen set that is said to be quite a step up in the lack of noise and vibration departments, though I have no experience with them.
A refer setup would kill a small bank of batteries in no time, hence the next rub, a bigger bank of un-cheap, heavy batteries.
My idea is to run nav lights, radios, pumps, cabin lights and the like while away from a plug on the dock. TV's, hair drieers, washers, garbage disposals, VCR's and the rest shouldn't be on the list, at least at sea. I have a nice home, shop, barn and land full of this and other bits of stuff I don't need at sea, nor would want to enjoy while out.
Propane powered anything under way is dangerous and unworkable regardless of the gimbals or contraptions engineered into them. I've seen some diesel powered stuff that work well, but the smell can be interesting to get use to. I also don't like the idea of a fire, however controlled aboard when I'm not (I'd always be afraid of the valve sticking at the wrong time)
You could also drag a prop powered generator or rig the shaft in the boat to spin the generator underway, with the expected draw backs.
Ice works well, it has no moving parts to break or ware out, stays cold for a long time in a well insulated box, is readily available in most places and doesn't cost much. All the things I like about engineering.
For extended cruising, wind isn't a bad idea. It will mess up the back of the boat a bit, make some noise and need steady healthy winds for heavy amp draw. Some boats, like mine, would be hard pressed using one as the boom and boomkins hang well over the stern. I couldn't stow my dink between the boomkins and still get at it safely. But if the need for the output is high enough, the boat rather conventional in layout, the drag issues okay, because you're cruising anyway, then they are fine and many people love their big props hung aft.
If I lived aboard again I'd consider both solar and wind generators. I currently use solar to trickle my batteries and vent the cabin. Putting a wind machine on a schooner is another thing I'd have to think through - like where to put the darn thing without it fouling something, mostly my head.
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