Wind Generators in Suburbia - Our Experience

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The idea of a wind generator has fascinated me since I first found out about them from an Earth Garden magazine article back in the ‘70s. Even in the early days I wanted to generate at least some of our own power and photovoltaics were still very expensive. There is also the issue of what to do when the sun wasn’t shining and a wind generator fitted the bill precisely, the wind blows at all hours not just during the daylight hours.

I looked at the available designs from the Savonius rotor made from old 200 litre drums or made from scratch with lighter (but more expensive) sheetmetal  (see the photo below taken at the “Sun Powered Eukey Complex" in Queensland), through to more conventional horizontal shaft generators where the wind turns a propeller, which turns the generator. In those days commercial models were expensive (if you could find one) and we had zero extra cash so anything I could get would have to be a home build.

Savonius Rotor Wind Generator

First Generation

I came across a design for a bicycle based wind generator which was not only within the price range I could cope with, it was also within my capabilities to be able to build it. It was a bicycle wheel, forks and head set, with metal over the spokes and a roller style bicycle generator (see photo). After being a local landmark (and eyesore) for a number of years it finally bit the dust over 20 years ago. Unfortunately, it proved to be all that photovoltaics were not:

1. It was not attractive, if you don’t believe me see the attached photograph. Speaking of the photograph, the reason for the poor quality is that the original (film) photo has gone walkabout and all I have left is this scan of the photo which appeared in Grass Roots Magazine no 71 (February 1989).

2. It gave off a noise in high winds that did annoy the neighbours, not to mention us too. The generator was mounted on the top of steel pipe which was in turn mounted on top of the garage roof, but braced to the house. The result of this method of securing it was that every little vibration was transmitted not only to the garage, but the house as well. It was mounted outside the dining room so this area got pretty noisy in high winds!

3. It required frequent maintenance, being a home build the wires were connected directly to the generator, no slip rings in between. The result of this is that every time the wind shifted (and here in suburbia with lots of turbulence it shifts pretty damn often!) the charging wire wrapped it self ever tighter around the support pipe. If I did not climb up and untangle the wire every couple of days it would either pull it out of the connector or stop the wind generator from turning to face the wind. Either way generation stopped.

4. At full belt it delivered less that an amp to the system, so even when it was working perfectly the output was miniscule.

Roller bike generator used as above

It was just not practical, even if it was home made from recycled parts. However, if all of this has still not put you off, you can find more information on how I built it here.

Second Generation

The lure of the wind generator is strong.

I always wanted to make my own, hand crafted and based on a car alternator, but with so many projects I never go the time. In early 2005, there were some Chinese wind generators doing the rounds, producing around 200 watts at 12 volts, the kit was self-contained (including a steel pipe tower) but the whole thing weighed 70kg, add wind load to that and it was a substantial amount of weight to mount on the garage roof.

(Note: These are not photos of my Chinese wind generator. These are the nearest approximation that I could find on the net)

It was also comparatively large with a blade diameter of 2.5 metres. I figured I better get council approval (it was a bit difficult to hide!). When I rang them and after the obligatory 1 minutes silence for weirdo identification they told me that inspections etc would cost $700 (although after much discussion I talked them down to a bit over $300) which would still add considerably to the costs of getting the damn thing up and operating (the original price tag was $450).

I also figured I would need to consult a structural engineer (expensive) because I did not have the technology to work out what loads would be involved and whether or not the garage was up to it. Would I have to reinforce the structure so it could cope with the loads? (more expense).

In the end I shelved the idea after concerns about the weight, costs and council hassles, I donated it to a local farm about 5 years ago.

Third Generation

As I said above, the lure of the wind generator is strong and while overseas I saw some much smaller and less obtrusive units in use beside the roads in the UK. After research back in Aus I found the AirX 400 watt 12 volt wind turbine, which is made in the US.

It was double the cost of the original Chinese unit but it was also twice the power (ie 400 watts versus the original 200 watts). Also it only had a blade diameter of 1.17 metres and weighed 6.5kg and was about as obtrusive as our next door neighbours TV aerial! It was perfect, so I ordered one.

AirX 400

To install it I mounted it on top of the pipe which used to support a Stationmaster CB aerial, which I no longer had a use for. That puts it about 4 metres over the top of the garage.

To be fair, vibration is still an issue and in moderate winds there is noticeable vibration in the garage but because it is mounted on the other side of the garage from the house, there is no detectable noise in the house, even in high winds. It is noticeably quieter, and has been no problem for the neighbours to date.

It had comprehensive instruction along with it, giving wiring dimensions for various distances between the generator and batteries, fuse requirements (50 amp!) and the earthing requirements which had me hammering a 50mm pipe two metres into the soil. This last requirement was for lightening protection. A comprehensive set of instruction was a pleasant and welcome surprise!

It does work as well as can be expected, but it needs to be about another 4 – 5 metres higher along with all of the added costs and council hassles associated with that. Even in a strong wind the output is minimal, about 5 amps, purely because the turbulence due to the surrounding houses means that the wind direction whips around quite a bit. To get the most out of a wind generator it needs to be high up, near the ocean or on the edge of a plain where the wind can build up speed and blow continuously from one direction for a while.

Mind you, I do get a kick out of watching it rotate and there is a small red LED that tells me when it is charging the batteries. Yup, just because the blades are turning doesn’t mean you are generating power. There is a critical propeller speed, below which you don’t get any power, for the AirX that is 500rpm.

Years ago there was a discussion on a UK based self-sufficiency forum I was part of where suburban wind generators were described as “chocolate teapots” and not as a term of endearment! Unfortunately after all these years of mucking around I have come to the same conclusion, at least in our area of suburbia. My suggestion is that if you really want one of these bad boys, take careful wind measurements in the area where you intend to mount it. Take into account not only wind speed, but direction as well. Does the wind blow steadily or is turbulence and issue?

More designs are coming out all the time so the one you choose may work better in your situation than ours did for us. Good luck!

 

 


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