# Solar or wind



## Windwardbow (Jan 6, 2011)

My wife and I live on our 25' sailboat. We are on the gulf coast right now and will be heading down the west coast of Florida, and then to the Bahamas. We have one 20 watt solar panel right now, which is enough for lights and chart plotter. It is not enough for my wife's computor. We can afford to get more solar, or a wind generator, but not both. We do not have refrigiration, and have no intention of getting any. What do other liveaboads do? Any advice on my choice between the two.


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## saildork (Feb 20, 2007)

Have you thought about getting one of the small Honda generators ( 1 kw or 2 kw) instead? They will provide all the power you need and more. And you can use them away from the boat as well.


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## Minnewaska (Feb 21, 2010)

My biggest objection to wind gens are how noisy and irritating they get. Even listening to the one on the mooring next to me drives me nuts.


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## Windwardbow (Jan 6, 2011)

No, I hadn't considered that. We only have a 25' boat, so space is at a premium. I don't think I would want to store it, feed it, and listen to it. Thanks for the thought though.


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## Minnewaska (Feb 21, 2010)

The honda 1kw gen is so quiet you could whisper standing next to it. I dare say the wind gens are louder when they are turning. Will generate juice for 9 or more hours on less than a gallon of gas. Can be used to recharge your batts, then get a 12v DC adapter for the laptop.


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## Omatako (Sep 14, 2003)

Given that you have probably quite a low power requirement, it's probably not necessary to go for the high-output fans that make a lot of noise. Something like a Rutland 913 that is actually quiet unless the wind is howling (in which case the gen noise is academic) will put out enough power to replace your draw.

Solar is OK but remember it only works in the daytime. I suppose the counter argument to this is that wind gens only work when there is wind but periods of darkness are guaranteed, a lack of wind is not.

My choice in these circumstances would be a wind gen.


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## mdbee (May 2, 2007)

It sounds like you have minimal voltage needs. I'm about to add a second 20watt panel myself. Mine in hung on the rear "pushpit". I think having a second one on the other side will be better; there is less of a chance of a shadow interfering with charging. 

Keep in mind, even a small shadow will dramatically cut your output.

PS: how many batteries do you have?


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## Windwardbow (Jan 6, 2011)

I don't know much about solar panels. The 20 watt kit that I have now I bought from defender for $260 last year. I have been looking at some panels on ebay, but don't know what a good brand is or what a bad one is. If I go solar (that's the way I'm leaning) I would probably get a 100 watt panel. Defender is alot more expensive than the ones on ebay, but there may be a good reason for that. I don't want to pay more than I have to, but I also don't want a piece of junk. I want a good panel at a reasonable price.


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## LakeSuperiorGeezer (Oct 8, 2010)

Laptop computers on average use 30 watts or 2.5 amps. How many hours per day do you use it? Lets say five hours so that is 12.5 amp-hours. Check here http://www.sailnet.com/forums/elect...and-913-air-breeze-kiss-wind-generator-2.html and see that message #12 states "0-4 Amp-hours per 24 hours in Hawaii. We have trade winds averaging 5-12+knots most days." Consider that the Rutland 913 costs about $1000. Now a 135 watt solar panel will be about $400 and you already have wiring and voltage regulator, so cut this in half for poor angle to sun and voltage regulation and figure 12 hours of daylight so figure 4 amps so you get 50 amp-hour per day. Search on solar panel here on sailnet for more ideas


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## teejayevans (Jul 10, 2005)

My laptop (which uses a 65 watt adapter), uses 1.5amps if already charged and at idle.
I have reefer and use computer 8 hrs/day. I use solar for 99% of my power, I run the engine if I run into a cloudy spell.
Tom


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## Omatako (Sep 14, 2003)

LakeSuperiorGeezer said:


> Check here http://www.sailnet.com/forums/elect...and-913-air-breeze-kiss-wind-generator-2.html and see that message #12 states "0-4 Amp-hours per 24 hours in Hawaii. We have trade winds averaging 5-12+knots most days."


In the same thread I questioned the calculations done by this member because they made no sense (see post#16). The calculations postulated by me suggest an average of 0.082amps of output. Clearly there is something wrong with either the member's calcs or his wind gen.

The member talks about "0 to 4 amp hours per 24 hours". Coincidentally the manufacturer's spec sheet for that unit talks about 4 to 6 amps output at 15 to 20 knots of wind. Methinks the member is confused between amps and amp hours. If he means 4 amps for 24 hours that amounts to 96 amp hours.

I speak of experience - I had one of these units on a vessel for a three month ocean voyage and we never had cause to start an engine to charge and we had no solar and we never had flat batteries. So for the draw expected by the OP, this unit would more than suffice.

I have no commercial connection to this charger other than my own experience and the strong probability that I will buy another one soon.


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## mdbee (May 2, 2007)

*Solar*

Check out this site. If you are handy with tools, you can fabricate your own.

Solar Cell, Solar Panel, Renewable Energy, Wind Energy, Charge Controller, Solar Trackers - Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers

A couple of my posts:
http://www.sailnet.com/forums/bristol/66588-re-custom-solar-panel-mount.html

http://www.sailnet.com/forums/pacific-seacraft/65223-where-did-you-put-solar-panels-3.html



Windwardbow said:


> I don't know much about solar panels. The 20 watt kit that I have now I bought from defender for $260 last year. I have been looking at some panels on ebay, but don't know what a good brand is or what a bad one is. If I go solar (that's the way I'm leaning) I would probably get a 100 watt panel. Defender is alot more expensive than the ones on ebay, but there may be a good reason for that. I don't want to pay more than I have to, but I also don't want a piece of junk. I want a good panel at a reasonable price.


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## LakeSuperiorGeezer (Oct 8, 2010)

*Wind Shadow?*



Omatako said:


> The member talks about "0 to 4 amp hours per 24 hours". Coincidentally the manufacturer's spec sheet for that unit talks about 4 to 6 amps output at 15 to 20 knots of wind. Methinks the member is confused between amps and amp hours. If he means 4 amps for 24 hours that amounts to 96 amp hours.


That could well be a miscalculation. The graph in the manual shows about two amps at 10 knots and 4 amps at 20 knots, but it could be the windwill was in a wind shadow while docked, a building of other boats could really slow the wind.


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## BUDGIE SMUGGLER (Jan 8, 2011)

i have been through all the solar/generator options and feel that the bigger solar panel is probably the way to go.... but i`m only going from motorhome experience..... i then had four 125 watt panels and 600 amps of deep cycle batteries. the panels fitted on the motorhome roof nicely. now that i`ve sold my motorhome and live on a 24 foot yacht...how the hell do i fit four large panels on it ? i may have to go for a generator linked to a very large battery charger and run the gen for an hour a day,not for general mains power but solely to charge batteries. i would then run computers etc off a small inverter.... your power needs are quite minimal so one 125 watt panel and about 120 amps of battery should do the trick. the only problem is.... that your power needs tend to increase over time and then a second and a third panel and more batteries are needed !!! or am i the only power hungry espresso coffee junkie who lives on a small boat!! i admire anyone who can live off one large panel....sadly i can`t go without my espresso machine (ten cups a day at 5 amps per cup) ,grinder, computer, portable freezer(50 amps per day) etc. etc. and the list goes on!!


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## bljones (Oct 13, 2008)

aussie1947 said:


> i can`t go without my espresso machine (ten cups a day at 5 amps per cup) ,grinder, computer, portable freezer(50 amps per day) etc. etc. and the list goes on!!


You ain't rollin an RV anymore- you're gonna have to start making some decisions. A 100+ daily amp draw is gonna tax ANY charging solution that is conceivable on a relatively small boat.


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## LakeSuperiorGeezer (Oct 8, 2010)

How well do solar panels hold up to the corrosive saltwater environment?


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## jrd22 (Nov 14, 2000)

On a 25' boat space is at a premium so there is an advantage to a wind gen. I like solar, no noise, no moving parts, etc. but in this case maybe a wind gen makes more sense, especially in an area known to have steady wind.

Here is a link to a good site for solar if you opt for that route.

Kyocera KD135GX 135 Watt 12 Volt Solar Electric Panel


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## marianclaire (Feb 4, 2010)

I have to ask. How much of the computer time is dependent on internet connection. In the areas you are headed it could boil down to little or no internet, little or no computer use, little or no power draw. Dan S/V Marian Claire


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## Windwardbow (Jan 6, 2011)

marianclaire, alot of the computer time is internet based. We have a Verizon air card. Hopefuly that well be ok in south Florida. So far along the gulf coast we haven't had any problems. 8 to 10 hours a day of computer time. It's not only computer work, the computer is also our tv and dvd player.


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## marianclaire (Feb 4, 2010)

I used a card type a few years ago and had no cell therefore no internet from the Keys up to Marco except in Everglades City. Enjoy the trip. Dan S/V Marian Claire


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## sailingdog (Mar 19, 2006)

I think solar makes more sense than wind on a boat your size, since a wind gen needs to be mounted high enough to be out of the way and such that it can't hit any rigging or sails or people. That is difficult to do on a 25' boat. Solar panels make more sense. I wrote a basic primer on sailboats and solar power on my blog, and *would recommend you read it.*

What will work will depend on a lot of things. First, what is your electrical usage? If you don't have a battery monitor, getting one would be a good idea. Second, what size is your battery bank? A larger battery bank will support larger loads, and increasing the battery bank size makes it effectively larger than the change in bank size alone due to the Peukert Factor, and the effect of the decreased size of the loads to the battery bank size. Third, the type of charge controller and size of panels you have will make a big difference.


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## norsearayder (Dec 19, 2006)

kyceroa panels are the only one with a 25 year output warrenty and are rated for sailboats.i have two,they handle all needs autopilot ,freezer,inverter,electronis & lights etc...i got them shipped from afordable solar out of arizona.best deal i could find without buying a pallett


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## norsearayder (Dec 19, 2006)

oh yeah there 85watt panels that put out 10 amps or so max...iam installing a wind gen when i install the radar


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## TQA (Apr 4, 2009)

Another vote for solar. 

IMHO the areas you are talking about will have too many sunny but low wind days for a wind genny to make sense.


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## sailingdog (Mar 19, 2006)

norsearayder said:


> oh yeah there 85watt panels that put out 10 amps or so max...iam installing a wind gen when i install the radar


85 watt panels aren't going to put out 10 amps... not realistic... a solar panel needs to put out about 14 VDC to charge a 12 VDC system...and 85 watts/14 volts ---->>>> 6 amps or so... realistically possible if you've got an MPPT charge controller.


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## TQA (Apr 4, 2009)

Most current solar panel manufacturers use a voltage of about 17 volts when calculating output watts.

85 w = 17 volts x 5 amps


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## sailingdog (Mar 19, 2006)

Which is why I mentioned the MPPT charge controller. 


TQA said:


> Most current solar panel manufacturers use a voltage of about 17 volts when calculating output watts.
> 
> 85 w = 17 volts x 5 amps


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## norsearayder (Dec 19, 2006)

when my bats are down & the sun is right, i have seen 9.2 incoming on my xantrex c35 controller.those amps dont usually stay at that rate very long before bats are quickly charging and the amps back off accordingly


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## newhaul (Feb 19, 2010)

they already have some solar i would recommend a small homebuilt wind genny they are easy to make and add more solar later doesn't matter where you are some days the sun don't shine some days the wind dont blow.


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## ArcherBowman (Jul 1, 2009)

Omatako said:


> Solar is OK but remember it only works in the daytime. I suppose the counter argument to this is that wind gens only work when there is wind but periods of darkness are guaranteed, a lack of wind is not.


Heh! I don't know where YOU sail Cochise, but here in East Tennessee, I can guarantee a lack of wind. All you have to do is consult my work calendar. If I'm off work, there's no wind.


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## Windwardbow (Jan 6, 2011)

Thanks for the advise everyone, I appreciate it. I think I am going to add one 100 panel and a mppt controller.


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## tomperanteau (Jun 4, 2009)

We're going through the same dilemma and we have come to the conclusion that you should have a mix of the two.

Solar will be my main source of power, but I will also have a wind generator to supplement. Solar is maintenance free and cheaper, so that will be the workhorse that is planned to handle most of the load. Wind will be the backup to help supplement.


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