Solar or Wind

[Paul_S123]

I know this has been discussed in the past, but with technology changing so fast..perhaps worth a revisit.

If the boat (Moody 31) is kept on a summer mooring in W Scotland, what is the recommended power source for charging batteries at rest and running tiller pilot and nav equip, while underway.

I have 3 batteries, 2 110ah leisure, plus a start battery.

At the moment they are controlled by a 0 - 1 - 2 - 1+2 switch, which I will probably change out to the Blue Sea with auto charging diode. If I do that, the charging diode needs 13.2v to charge all the batteries, so pref would like to get that output from the charging source.

I was ideally looking at a Rutland 504, unless there's a better option.

 

[pessimist]

We have both. The solar provides a more reliable and (in summer) higher output. The wind generator provides higher amperage but typically only in short bursts.

 

[robmcg]

We are Scotland based and have both wind and solar. Our wind charger definitely puts more in than the solar does (Rutland 913/80w solar panel). Forget the Rutland 504 and invest in the 914 with the mppt controller. No need for a fancy battery switch, will just cost you money you don't necessarily need to spend.

 

[macd]

We have both. The solar provides a more reliable and (in summer) higher output. The wind generator provides higher amperage but typically only in short bursts.

I don't doubt you're right, but that doesn' tell the OP much if he doesn't know what type of wind gen and wattage of panels.

 

[Allan]

I sail two boats, one has wind (913) and 100w of solar, the other has 150w of solar. Both have one fixed 50w panel which ensures the domestics are in good condition when the boat is left. The 50w on one boat and the 100w on the other are roving and can be pointed toward the sun. A few key things,
1. Adjusting the angle/direction is key to getting plenty of power.
2. Wind driven generators are very expensive in comparison to solar.
3. Having plenty of storage, batteries, are very important and cost effective.
4. Thinking about your usage is very important. I can run all 5 LED lights in my saloon for the same power as one of the lamps I removed.
The boat on which I have done the most miles this year has a wind pilot. That helps greatly, as does the LED masthead tricolour.
Hope that helps the OP.
Allan

 

[KellysEye]

Giiven the amont of rain and strong winds in Scotland, north-western coast has about 265 days with rain a year and this falls to the south east to a minimum of about 170 days along the coast to the east of high ground, would solar panels be a good idea.

 

[pessimist]

I don't doubt you're right, but that doesn' tell the OP much if he doesn't know what type of wind gen and wattage of panels.

Fair point. The wind generator is a KISS (can't find the performance figures offhand). 240 w of solar, 1 fixed and two roving.

Mainly in S.W. England (Dartmouth mooring)

 

[Allan]

I read somewhere, sorry can't remember where, that the average wind in the UK ranges from six to ten m/s. Marlec claim that gives 80-110w from a Rutland 914i for £650. Solar panels are around £1.40- £1.80/w.
My guess would be that the cost per watt is slightly cheaper for solar. Say 100w for 24hrs, £650 for wind. 100w for 6hrs, £160 for solar. The big factor for me is that whilst, as sailors, we want wind, we don't want too much. However we can't have too much sun!
When was the last time you recommended an anchorage or mooring by saying "You'll find there's plenty of wind there".
Allan

 

[Mistroma]

I'd agree that a Rutland 504 would be a waste of money as it would probably only average around 1-2Ah/day.
A Rutland 914 might average around 13Ah/day over the season but an 80W solar panel should average closer to 20Ah/day. The Rutland would probably cost more than £800 to install versus under £200 for a rigid 80W solar panel.

Figures above based on West Coast of Scotland, solar panel with no shadowing and wind-gen mounted approx. 3m above sea level. I've been keeping daily records since 2009 based on West coast and then sailing to med. Obviously solar output increased and wind-gen decreased. However, I'm pretty certain that the figures I've used won't be miles away from the truth. I often see quotes about wind-gen being better in Scotland but never saw any evidence. I must admit to anchoring in sheltered locations.

OP seems to think that there might have been a recent step change in either wind or solar power. There are probably three things to consider:

1) Available energy in an average year won't change unless you change either sailing habits or cruising area.

2) Change in relative cost of wind versus solar. Tends to favour solar with no moving parts and big investment in large scale production. Investment in wind power is unlikely to result in small, cheap, mass produced wind-gens.

3) Big increase in efficiency of solar or wind-gen. I haven't rechecked calculations recently but would not expect a huge increase in wind-gen efficiency and larger but not huge increases in efficiency of solar. I seem to remember both being fairly low vs. theoretical limits (guessing in region of 50%. of what it theoretically available).

It's a complex field but in general I would not expect small wind-gen prices to make a step change. Solar should therefore continue to be the most cost effective solution by quite a large factor (~7 or 8).

 

[dunedin]

Personally I would go with solar only. We fitted 100w in two semi-flexible panels on the sprayhood, plus another 100w only used on anchor. Surprisingly effective, and much less noise than wind generator.

Boat based Clyde and northwards in the summer - unlike KellysEye pessimism, had lots of sunshine on the panels (particularly this autumn) and the longer daylight hours in the summer helps.

 

[oldsalt]

Got both for the Clyde. Solar (140W panel) excellent, but useless at night or during grey days which we get a lot of here. Further south I might go for solar only, but here I will use wind as well. Recently a windy night at Loch Ranza... wind generator (Air Breeze) allowed the heater to work all night with no battery drain. If budget is a problem then solar is better value.

 

[doug748]

The Rutland 504 would probably be fine unless you take long day sails 4 or 5 days a week. Windgens are great at topping up modest batteries, on swinging moorings, between trips in normal summer usage. They are expensive at the outset but have a long life, I have a similar sort of thing and it has been going strong for over 25 years. It does not produce much umph but it does not have to, it is going 24 hours so even .5amp gets you there.

Another downside is that they are rather hopeless in a marina or the average boatyard.

You can fit one and forget about it, though I would probably switch it to one service battery at a time and alternate...or get the larger unit...or double up with a small panel

Be wary of well meaning advice from people with large boats whose power requirements are a quantum removed from a 30 foot yacht......unless you yourself have a fridge, 12in plotter, radar and PC on board., in which case God be with you

 

[LadyInBed]

Daytime downwind sailing in light airs, you need solar.
Beating to windward at night, you need a WG.
Sitting at anchor for a few days taking in the sun, then solar.
Hence, I have both. . . . and a mains gen just in case!

 

[TQA]

Do not underestimate the maintenance requirements of wind generators. While a few run untouched for years many require new bearings annually. Blade failures happen occasionally and the resulting severe vibration usually wrecks the generator and the mounting pole. Also be aware that some makes of wind generator are noisy, really noisy old 707 on take off noisy.

I live on the hook and off the grid in the Caribbean. My Kyocera rigid panels are coming up to ten years and are still producing about as much as they did when new. I have helped out on diagnosing problems and early failures on cheap non marine rigid panels and semi flexible panels. The connections corrode into piles of green goo and the flexible one delaminate. The UV is pretty fierce out here.

In your position I would fit the largest rigid panel you have space for and a good quality wind generator with an overspeed brake.

 

[JumbleDuck]

I have 3 batteries, 2 110ah leisure, plus a start battery.

I have 2 x 60Ah domestic batteries and 2 x 50W semi-flexible panels, which have been fine for all my modest needs (GPS/AIS, radio, LED lights, old B&G instruments taking 4A, charging phones, tablets and laptops) on the west coast of Scotland. This year one of the panels went titsup - not sure why yet - and that made things much more marginal On that anecdotal basis I'd say that you'd be fine with 100W - 200W of solar, depending on how many power-hungry toys like plotter and fridge you have.

 

[lpdsn]

If the boat (Moody 31) is kept on a summer mooring in W Scotland, what is the recommended power source for charging batteries at rest and running tiller pilot and nav equip, while underway.

I bought a cheap 100W rigid solar panel. Key word is cheap: it was £89 for a 100W panel. I use a cheap controller too.

Partly it was just a general experiment to see if it was useful and partly it was because a couple of times I've overwintered in a marina with a high daily rate for electricity, even for berth holders, so I wanted something to keep the batteries topped up when not plugged in.

It's meeting that second requirement now. I can't say I'm getting a huge current at this time of year (not much more than an Amp and often less), but the panel is horizontal and Ireland is no more renowned for its days of endless sunshine than Scotland. It is doing the job I bought it for.

During the summer I measured 1A in the afternoon during pretty heavy rain (of the rain all day rather than a squall sort) in NI. Late March I measured 4A in spring sunshine. It's rated at a bit over 5A peak.

I sometime deploy it when sailing and sometimes not. It won't keep up with the normal nav plus fridge load, but it certainly helps. I only use the autopilot for short burst when under sail, so I can't speak of the impact there.

 

[Kelpie]

Giiven the amont of rain and strong winds in Scotland, north-western coast has about 265 days with rain a year and this falls to the south east to a minimum of about 170 days along the coast to the east of high ground, would solar panels be a good idea.

Offset this against 18hrs of sunlight per day around midsummer, and it's nowhere near as bad as you might think.
We never seem to struggle for electricity and have a 50w cheap rigid panel plus engine charging, via typical cruising engine usage. I have never connected to shore power in my life!

 

[sailaboutvic]

We have 200w solar panels and 914 WG , I never reckon much on the 914 , but I have to say since we removed it are batteries the last few months haven't been as good as before , so I guess we missed judged how much it helped to keep our batteries topped up on clouded days and at nights .

 

[NormanS]

We have both. WG was a 913 until it flew apart in a gale in August. Thought long and hard, and eventually replaced it with a 914. The PV panel is a rigid 100w, fastened down on the coach roof, and cost about £80. The PV panel was brilliant in the fine bright sunny weather that we had in the Spring and early Summer, but obviously not so good in the grey weather later on. £ for £, the wind generator wins, - silent, no moving parts, and dirt cheap to install, but it's good to have both systems.

 

[LadyInBed]

We have both. WG was a 913 until it flew apart in a gale in August. Thought long and hard, and eventually replaced it with a 914. The PV panel is a rigid 100w, fastened down on the coach roof, and cost about £80. The PV panel was brilliant in the fine bright sunny weather that we had in the Spring and early Summer, but obviously not so good in the grey weather later on. £ for £, the wind generator wins, - silent, no moving parts, and dirt cheap to install, but it's good to have both systems.

Did you mean to say Solar?