Mahe 36: Wind Generators

[MKB53]

Mahes

One of my recent additions for the winter cruise north was a wind generator. One of the forum members expressed an interest so I am putting up a new thread with the details.

Basically it worked pretty well but there are two issues from my installation that I have learnt from, as a newcomer to Wind Generators.

I bought a Southwest AirBreeze unit, apparently rated at 160W. I have seen claims of 500W output for others but having used this a while I wonder whether those are realistic claims.

In a good breeze (15Kts apparent) it will put out 10-12 Amps easily. At it's kick in speed of about 8Kts you seem to be getting about 4 or so.

Bottom line is that in a good breeze on a good reach or to windward it will keep up with demand including the autopilot. Downwind it delays the need to fire up the engine considerably. Today I was on a beam reach in 18 - 22Kts of wind and between the windgen and solar panel the batteries were actually charged up on the 3 hour run.

We have had the misfortune to have to sit out some strong winds in windy anchorages and did not have to run the engines for a couple of days. No sun either!

In our circumstances I feel a mix of solar and wind makes more sense than purely solar.

I only reviewed a few generators and selected the AirBreeze largely because of it's integrated regulator. Many don't do this and expect you to install a "dump" style regulator which I don't like. It is also well represented in the local market.

The two issues?
a: It is a bit lower than the ideal hight for peformance (my fault as I wanted it to fit in asthetically) and

b): It is about 20mm too close to the boom. I have a couple of dings in the tip of the blades that show the exact amount! This was quite difficult to measure when designing the mast and basically we screwed up.

With my set up both can be easily remedied and I still like the basic setup.

The height is mainly an issue at anchor as the boom interferes with the airflow as the boat swings. When sailing it is never a problem.

I will put a follow up post in the thread with pictures and dimensions.

Cheers
Martin

[MKB53]

Mahes

Installation details.

The mast is 2.7M from the deck to the top. The unit clamps on the pipe and the center of the boss is a little higher. At this height it is well clear of heads and normal reach. Installation instructions are simple and clear.

The mast has a 45deg dogleg at rail height (about 900mm) to shift the unit aft as there is no decent mounting point far enough back on the hull. The offset of the dogleg is 32cm.

It is made of 80mm s/s tubing to give it better rigidity and narrows at the top to the correct diameter for the unit.

The unit is stayed fore and aft at about 900mm down to the deck and laterally to the davit. This lateral stay is fixed quite high up the mast and I will probably drop it down when I make my modifications.

The mast has a 150MM S/S round base plate that is flattened on one one side flush with the hull. It is bolted on with 4 10mm bolts, 2 of which go through lip of the hull/deck join and 2 which go through the deck into the engine compartment. There is a strip plate under the lip and a bigger plate under the 2 inner bolts rather than washers.

On my installation the dogleg is also set at 45deg to the fore and aft line. This will change as I need to rotate it to move the unit further back and clear of the boom. In it's current position it is about 22cm aft of the mounting point and rotating it to 90 deg will add 11cm - enough to clear the boom easily!

The wiring goes down the mast and via a stop switch to the batteries without any long cable runs. The stop switch is essential in my view. It puts the brakes on the unit so it can be handled safely or just to stop generating. Another plus for the AirBreeze. I bought waterproof box to fit the switch. My advice is to get a good sized box as it is very hard to bend the heavy guage wires into the small box that I used.

Hopefully these pictures illustrate the instalation adequately.

Cheers
Martin

[MKB53]

PS: The GPS antennae still seems to work fine. I was concerned that the extra steel and liferaft would affect it but it still gets a DOP of 1.5 to 2 in open waters.

[kolbywhite28]

Your wind generators must be in a good condition so that it can give you a nice sailing. Must check first with your wind generators' connection.

[careka]

MKB53
the way you have bolted it to the deck, must be giving you a lot of renosance noise into the hull of the baot ?
normaly there is a rubber fix between the deck and mast to take most of that away .
Do you have a lot of noise ? or is there some rubber we dont se on the pictures.

(hope i spelled that rigth)

[mbianka]

I agree having both solar and a wind generator is a good way to go. I have a little more complex energy need as I have electric propulsion and so bought a 48 volt wind generator (Marine AirX) for my propulsion bank. During most days it does not turn because the solar panels keep the bank topped up. But, while riding out Hurricane Earl last year I was glad I had the wind generator available to tap into all that wind energy flowing passed the boat:
THE BIANKA LOG BLOG: AN ENERGY EPIPHANY
I also like the on board regulator feature of the Southwest units.

[SimonV]

I also have the Air Breeze and cant fault the operation......although I do have a most enoying tick when the fan is turning realy slow, sort of a plastic sound....I will lower it and see what it is. I am just having too much fun up here in the Whitsundays to do work.

[Edmund]

Thank you very much for sharing valuable information, Martin. A nice setup!
I am planning to do the same installation (Rutland generator), and was thinking more or less the same way as you have done.

Do you feel it is stable enough with only two legs, in any weather? I was considering a third, removable leg, crossing the stern, to be removed whenever we need to use the port stern to access the boat in harbour. But it is perhaps not necessary?

Edmund

[MKB53]

Hi Careka

The mast is only mounted on a sikaflex base. I considered a rubber pad but was pressed for time prior to the trip and did not get one in time. I am not aware of a lot of resonance but I sleep in the stbd hull! My guests have not complained yet either.

At low wind speed (before it starts charging) there is a bit of a rumble but when the fan speed gets up it is quite smooth. It makes sense to have a pad and when I do my mods I will probably fit one.

Regards
Martin

[MKB53]

Edmund.

If you shake the mast with your hand it will move, it is not rigid but is quite steady in normal operation. I don't think it is necessary to have an extra brace on mine. Note - do not brace to the rail, that is not good enough, I tried it, the hull is the best and the davit an adequate second.

I have been in 30Kt winds in short seas so far and it has been fine. And some quite strong "bullets" while anchored.

[careka]

Thanks MKB
and Edmund, go for a better one then the Rutland,

[cburger]

A friend mentioned to me that there any be wind generators for the marine market that can be hoisted up a haylard when required and taken down when not in use. Anyone ever heard or seen of this type?

[atoll]

Originally Posted by cburger

A friend mentioned to me that there any be wind generators for the marine market that can be hoisted up a haylard when required and taken down when not in use. Anyone ever heard or seen of this type?

windbugger

[SimonV]

Originally Posted by cburger

A friend mentioned to me that there any be wind generators for the marine market that can be hoisted up a haylard when required and taken down when not in use. Anyone ever heard or seen of this type?

The Hamilton Ferris water towed Generator has this option but is a poor wind gen, but a great water driven Gen..

[Mark Johnson]

The notion that wind generators, (like the most noisy brands from SWWP), are necessary to fill in for when it is cloudy, and solar doesn't work, is an often repeated myth. It is simply not true...

If this has been the case for you, you don't have a proper solar array and battery capacity. We have had all solar for 15 years, and get all of our energy back to 100% charged, about 350 days a year. On the 16 remaining days, we crank the engine for 45 minutes or so.

The key is to have a solar array that produces bit over TWICE your normal daily consumption. If you start out with a super efficient boat, and minimize your consumption, this is entirely within reason.

Solar panels don't drop to near "0" output on extremely overcast days, they drop no more than 50%!

With our daily need in the range of 45 Ah, our 340 Ah Trojan L-14s can cover us for several REALLY overcast days if necessary, and by cycling them very shallow 90% of the time, we can easily get > 10 years out of the batteries with a VERY high reliability.

Wind generators often create extra shade on your best solar panels, which negates their supposed advantage, they only last 1/3rd to 1/4th as long, and like any other form of 24/7 noise brought into an otherwise bucolic anchorage, they are very inconsiderate to those of us who went cruising to avoid this very sort of thing.

We used to supplement with a wind generator on our last two boats, but after switching to all solar, we never looked back. Our neighbors in the anchorage appreciate it too.

M.