effectiveness of solar & wind

[Valiente]

Originally Posted by Newport41

Well this has brought up a few questions for me. First of all I'll let you know what I'm planning on here. We've got six Trojan T-105 golf cart batteries with a total (rated) capacity of 675ah. I don't want to run our poor old universal to charge the batteries. We have pretty minimal electronics. LED running lights and cabin lights, computer was designed with no moving parts and a 12'' LCD, small compressor/evaporator refer with interior closed cell foam inserts for extra insulation in the tropics, low draw fans, foot pumps for the sinks, monitor windvane, Raytheon sailing interments, small and simple GPS, and a conservative Furno radar. I figure our daily consumption at about 100ah. I know that these estimates are always low but I am assuming that we'll only use the windlass and electric autopilot when motoring or when we'll be motoring soon.

Your set-up fairly closely mirrors what we are putting together. Ideally, I want enough reserve to spend seven days or so without starting the engine for electrical generation, and with the assumption that I will get 8 hours of usable sun five days out of those seven. I don't expect to keep a full charge; I do expect to draw down multiple AGMs to 50-60% gradually on the basis of "three amps out/two amps in" logic.

I am not entirely convinced I need a wind generator...yet, because I have pipe "lifelines" and a pilothouse roof and will build an arch to hold panels, like Cruisingdad's, and an easily stripped-off bimini. So I might have enough surface area to just have solar as the top-up device. I am installing a Xantrex RS2000 charger-inverter by May or so, and will be able to start making "real-life consumption" estimates, even with just two Seavolt 6 VDCs and one 12 VDC start battery (all flooded lead-acid types). I will see what I eat and excrete, so to speak, with 30 amps of shore power, with a stock 55 amp alternator at cruising and motorsailing speeds, and on the hook with no charge available (haven't bought a Honda portable genset or panels yet).

This will be a start to establish where the investment in gear should go. But the goal is the same: a conservative use of total amps, plus the ability to generate from the sun (and perhaps the wind) enough of a surplus to keep us running the diesel for power as much as possible.

[Idiens]

I started off thinking all solar, because the wind doesn't blow well where I like to anchor and the blades make a lot of noise. The DuoGen looks neat, but expensive, and I have a lot of clutter on the rear deck anyway.
What has slowed me down is the top-weight and the drag. My rig and wheelhouse are already pretty robust. She's not particularly tender, but 25 knots and 20 degrees heel are my reefing guides close hauled (also to reduce weatherhelm). When I looked at how much 240 Wp of panels, plus supporting structure, weighs, plus height above water line.... hmmm. Then my past involvement in aerodramatics taught me that drag loves sharp corners and standard panels have lots of those. So there will be more drag from them than looks likely from their size. Not that 240 Wp of panels are particularly small.
My More Intelligent Partner suggested that maybe taking them down before sailing might solve my draggy top-weight concerns. - Which would be OK if I had a towed generator and suitable places to store them.
Then I find that the more efficient monocrystal panels loose power very quickly with any shadow at all. Nearer the equator that may not be such a problem but here in the 40's there is nearly always a shadow cast by part of the rig. I would need 480 Wp to compensate.
MMIP also suggested if the panels were moveable, then they could be always deployed somewhere sunny side up.
On the basis that experience is better than theory. I went for a 32Wp flexible panel. This has the disadvantage of being the less efficient, but is a shadow tolerant thin-film type that can withstand a bit of moving about. At the moment it is bungied to the boom facing south and has kept my battery bank happy all winter. I would need another 7 to reach my desired 240 Wp for operational use but I could add them one at a time. The cost differential is a bit frightening though. Maybe the DuoGen is competitively priced....

[ebs001]

I have 160 watts of solar and an Air-X 400. I have a Honda 2000. which I run every 2nd day or so. My discussions with other cruisers is it's the only way to go. A friend lent me the Honda. I will probably buy the 1000 next year. The 1000 will fulfill my charging draw and is smaller and quieter.

[Idiens]

Originally Posted by ebs001

... The 1000 will fulfill my charging draw and is smaller and quieter.

Retrospectively, if you initially had the geset, would it be worth adding the solar and wind generators?

[Brezzin]

Originally Posted by ebs001

I have a Honda 2000. which I run every 2nd day or so. My discussions with other cruisers is it's the only way to go. A friend lent me the Honda. I will probably buy the 1000 next year. The 1000 will fulfill my charging draw and is smaller and quieter.

Based on the specs I read, these units only put out about 8amps which can't be right. How long do you run the Honda?

Dave

[sailingdog]

Originally Posted by Idiens

Retrospectively, if you initially had the geset, would it be worth adding the solar and wind generators?

The advantage of solar and wind is that they do not require fuel. Fuel is heavy...and expensive nowadays... wind and sun are free and don't weigh anything.

[camaraderie]

Brezzin...you're getting AC/DC mixed up I think. The Honda 1000 operating specs are:
AC Output 120V
1000W max.(8.3A)
900W rated (7.5A)

900Watts= 120V x 7.5 AC
900Watts= 12V x 75 DC

The A/C output of the alternator used to drive the battery charger on board will yield a 75amp DC current (with some loss due to conversion efficiency). Remember the 10 x rule....multiply AC amps times 10 to get DC amps. (US ONLY!!)

[Idiens]

Originally Posted by sailingdog

The advantage of solar and wind is that they do not require fuel.

Yes, but catching the wind or the sunshine is not for free. However, going back to global warming.....

[sailingdog]

Originally Posted by Idiens

Yes, but catching the wind or the sunshine is not for free. However, going back to global warming.....

The Honda genny is cheaper than a good solar setup or wind generator... but the fuel cost over the long run makes it far more expensive.

[Idiens]

I've got an old Honda generator - 300W side-valve four-stroke. I not sure if I carry it for ballast or sentimentality (I inherited it from my father). Since I have only run it one a year - for servicing - it probably is using too little fuel.