Solar Pannels versus Wind Generators

[bestintentions]

Hi

I am thinking of adding either a Solar Pannel or a Wind Generator to provide enough power to run a GPS & basic instrumentation. Does anyone have any tips on which approach is best. I guess the best approach is a bit of both ....

Thanks

 

[Stingo]

Yep, have to agree on having both.

The problem with a wind generator at anchor is that we tend to anchor where there is no wind so solar panels become the main source of charge. At sea, a wind generator doesn't work well when going down wind.

The problem with solar panels is that they only work efficiently for about 6 or 7 hours a day if it is a cloudless day.

At anchor you'll want to leave the GPS on so that you can use the "anchor guard" facility

 

[davidbains]

!!

I have used solar panels in the Med for many years now. As Stingo says one usually anchors in a sheltered spot so a wind generator doesn't take over from the panels at night.
The generator is more effective in open waters but still noisy for what they supply which isn't much downwind. Apparently they really come into there own in the Windies where the wind blows all night at anchor, while you're watching DVD's!
I may still get one eventually but only after fitting a tall arch so no crew can stick their fingers in the windmill!! /forums/images/graemlins/shocked.gif

 

[Marsupial]

Hi

I have been researching this very topic and after a lot of ear bending I have what I believe to be the answer. I explored towing generators, windy things and solar.

My intention is to use the equipment in the eastern med, my solution is to fit two 35 - 40 watt semi flexible (what ever that means) solar panels on the deck. Independent experts have confirmned that towing generators are great but the boat must be moving (obvious) wind generators are not so great, downwind they dissapoint, at anchor they annoy - no wind no power. So when they are working they drive you mad, when there is no wind its hot, you have no ice. . .

To acheive a 40 watt boat there are a few things to do, fit a keel cooler to the fridge so you can dissconnect the fan approx 2 amp hr assuming it runs 100% of the time, run a simple GPS with a yeoman plotter - less than .5 amp hr.

The scheme just about works but I conceed that it may be nessacary to run the engine from time to time. Certainly in the UK I would rethink solar, and have to go for a geny of some sort.

Incidentally I had a alternator failure on a car today and learned that nissan primeras have a 80watt (or larger!) hitachi device (it looks like the one on my Yanmar anyway but the yanmar is only 55W)- breakers yard here I come.

Cheers


David

 

[Anonymous]

[ QUOTE ]
I have been researching this very topic and after a lot of ear bending I have what I believe to be the answer. I explored towing generators, windy things and solar.

My intention is to use the equipment in the eastern med, my solution is to fit two 35 - 40 watt semi flexible (what ever that means) solar panels on the deck.

[/ QUOTE ]I've done the same research and decided on two 180W panels - i.e. 360W in total. However, I *stress* that I'm not suggesting that you are wrong - it all depends on which route you want to go. We have a 20A watermaker, would like to boil the odd 12V dc kettle to save gas, and I like to use the autopilot and keep the radar running at sea. We also have a large fridge (keel-cooled), half of which can be a freezer if we set it right down. All high-power stuff. It's interesting to see different solutions; there is no 'right' or 'wrong' answer, I suspect, although we are both agreed to go solar not wind. By the way, I also have a 6kVA generator but would rather not have to use it when in crowded anchorages - at least not for too long at a time.

 

[Talbot]

You need a lot of deck space for 2 x 180w panels. I have a single 180w mounted above my dinghy davits. I plan for a duogen wind/water to provide the additional power, as I dont believe 2 x180 can supply enough for what I want to be able to do.

 

[Anonymous]

[ QUOTE ]
You need a lot of deck space for 2 x 180w panels.

[/ QUOTE ]Mine are going over the bimini - I have a massively strong ss welded tubular structure supporting the bimini and sprayhood which is totally wasted area. The solar panels will help to shade the bimini.

[ QUOTE ]
I plan for a duogen wind/water to provide the additional power, as I dont believe 2 x180 can supply enough for what I want to be able to do.

[/ QUOTE ]I have the 6kVA generator - it all depends what sort of cruising and power consumption you are aiming for. The Duogen would be pointless for us because we will be in the Med and expect around 60% of our time under way to be under power, when the alternator will be providing all the electricity we need. Besides, we aren't aiming to be under way for a high proportion of each week and the Duogen (in the water power mode) is only of use when you are under way under sail. It is a perfectly good wind generator, of course. My personal choice would have been a portable petrol generator in addition to solar had we not bought a boat which already had a diesel generator, because wind generators are not without their drawbacks and the supply of wind is as fickle as the supply of sunshine.

 

[henkm]

A quick thought: if it is *really* just for a GPS and basic instruments (VHF, log?) you will need none of both, unless you are sure you won't be motoring even half an hour in a week...

Henk

 

[Marsupial]

Hi Henk

Yes that was my thought, on passage we need a method of finding out where we are and maintaining a plot and a method of keeping food - a few lights and possibly some auto helm. This is roughly 40 watts constant load day and night, so 2 x 40 watt panels would do assuming there is sun and it lasts for more than 12 hours a day. in the eastern med in the summer it does so there should always be a surplus. As for wind and depth sounders they dont use much and switching them off makes no difference to my sailing /navigation ability and the boat goes just as fast/slow.

Radar is a power hungry beast so we have a sea-me thyat also uses next to no power on standby, when it blips we look around and perhaps switch on the radar.


Note : sorry about mixing up watts with amps in my previous post - but it had been a hell of a day- no doublt I will bore you with it one day!


David

 

[Sea Devil]

I went everywhere with a wind generator and then added two solar panels. There is no doubt in my mind that the value of the solar panels far outweighed the value of the wind genny -
The solar panels were putting in something all the daytime and stacks around mid-day except very overcast days....

Wind gennies do not do a lot when you are sailing down wind - unless it is really blowing hard - When you anchor you try to find a sheltered place so out of the wind -

My wind gennies tended to be noisy and needed switching off at night...

If I go again it will only be with solar panels

You might come to different conclusions for UK waters but nobody is going to spend very long there if other options are open

 

[Sea Devil]

I think you will find the autopilot burns amps at a frightening rate - Frankly I only helm coming into port or anchorage - The night sailing amps problem is also qiuite demanding in amps - Nav light(s) - compass light, instrument lights, autopilot running, Gps and wind instruments.... And thats before lights get switched on for watch changes, going to the loo or looking at charts.

Radar guard zones are rather problimaical in any except calm weather - I never keep mine on because of that and amps - I use a CARD radar alarm deep sea when I sleep.

 

[Talbot]

I did a full energy budget and included nightime sailing, the need for a decent autopilot and fridge/freezer plus use of CD/DVD, SSB etc. 2x40w would not even suffice for daytime use. Trade wind sailing demands a water genny rather than wind, but needs also to be available when at anchor. Thus a duogen is a great solution. Obviously consumption does reduce when at anchor, but also the duogen will produce less power when at wind mode, than in water mode.
No wind and no sun = no energy, thus I also have a small back-up petrol gennie.

 

[bestintentions]

Thanks for all your help with this. I think I will start with one one 32W flexible solar panel for this year (mainly only weekends and a 3 week holiday this year in GB/holland/Germany) and then probably also add another and a small wind generator when I sail south into the sunset (hopefully 2006!) A petrol genny is a nice idea too - will give it some thought

Re the solar panels the USF32 type look pretty good to me.

http://www.unlimited-power.co.uk/Uni-solar_Flexible_Solar_PV_Panels.html

Always cheaper not from a chandlery .....

Anyone got any experience of the vertical axis wind generators that you can put up the mast?

Thanks again!

 

[Anonymous]

The output of the vertical axis generators is very low - you need to check output vs windspeed and see if that suits your needs. As you will have seen from the discussions here, everyone has different objectives and cruising style/area so there isn't a single 'right' or 'wrong' answer. Read as many threads like this as you can and research the market. Power is the single most important decision for a cruising sailor. Too much wastes space and money, too little puts constraints on lifestyle. Some folks are happier with a hurricane lamp than electric lights - we are all different.

 

[slavkod]

Last year (2004) I have sailed 6 months in Greece and Turkey. We have 6KVA generator on board and a lot of electrical staff. Our daily consumption is at average 130 Ah to 150 Ah. We have met some boats in Aegean see which had both, wind generator and suncells. Most of the time they did not use diesel generator. When meltemi blows, which is most of the time from end of June to late august wind generator does the work. The same goes for solar panels as Greece have 7,5 hours of sun on average day. Based on this I am installing wind generator and sun cells on my boat. I think both will reduce diesel generator time for more than 50%.
Slavko

 

[Windchase]

I've been using a Rutland 913 for the last 2 years in the Med, with an ammeter to check the output. There is less than 1 amp until the windspeed is over 12Kts., then it rises quite nicely, over 5 amps at about 20Kt.
I found it was useful on those occasions when pinned down at anchor by a strong Meltemi for a few days - it kept the fridge battery charged. I left it running day and night, its not too loud even in strong winds. But given the choice now, I'd rather have the money back to spend on diesel.

 

[AndrewB]

After doing all the sums, we've decided against replacing our solar panels. They don't last forever, and it simply isn't cost-effective as against carrying some extra diesel to use the engine to top up the batteries.

This decision is partly because in the past our daily demand has been a comparatively low 40Ah (equivalent to less than 2 litres of diesel consumption daily), and we do have a towed generator which makes up some of this. With serious electrics aboard, I would fit a small IC generator.

 

[CharlesM]

my 2p's worth

<<Soap box, so ignore the post if yo are not bothered>>

I think it is every Jo and Janes duty to do what we can to reduce pollutants into the atmosphere, even if it involves spending a few hundred quid to prevent us having to burn a couple of litres of feul a day.

You may say 'My 2 litres a day less is going to make no difference'

I remember in the mid 80's at varsity arguing with a mate about using aerosol deodorants. His argument was similar.

Today the aerosols are a lot less damaging to the ozone, and the hole is either closing or projected to start closing soon. This is not because 1 person stopped using aerosols, but because lots of '1 persons' stopped.

Perhaps if we each do our little bit, we may actually save the planet.

<<off the soap box>>


Later
Charles

 

[Anonymous]

How old are your solar panels, and what manufacturer and type? They are supposed to last between 10 and 20 years, I had understood. Not good to hear of failures.

 

[cliffb]

Erm... Andrew...
'Scuse the ignorance...but what's an IC generator?

Thanks
Cliff