Wind Turbine FAQ's
The following information provides answers to many of the questions you may have. If however you cannot find the
information you require, please do not hesitate to e-mail or call and we will get back to you as soon as possible.
You will also find this information extremely helpful in making a decision about product suitability.
Thank you.
Information on wind speed.
Are these prices for real? What's the catch?
Will I only have power when it's windy?
What are the dimensions of the turbines?
What power wind turbine do I need to power my house?
What size turbine should I buy?
How is the energy harnessed?
Does your wind turbine produce 1kW per hour or per day?
Do I need planning permission?
Where should I site the wind turbine?
How much noise do these make?
The survival wind speed (40m/s) seems low?
Can I get a grant for these systems?
Can I connect the wind turbine to the grid to sell the electricity?
How much maintenance do the systems require?
Are spares available?
Will the system need to be inspected by a electrician or be installed by an electrician?
What is the best way to utilise wind power?
What batteries should I use?
How many batteries do I need?
What is the recommended system voltage and wattage, and why?
How do I connect the batteries?
Where can I get the cables for the batteries?
Can I use the 200W/300W wind turbine with 12v (or 500W/1000W turbine on 24v)?
How do I tell how charged my batteries are?
Why does my inverter shut down unexpectedly?
Should I balance the blades before use?
How do I balance the blades?
Do I need to protect my turbine from lightning?
Wind speed in your area is a handy thing to know before siting your wind turbine. The rated wind speed on wind turbine differs between the various makes and models so its best to the wind turbine that suits your area. The rated wind speed on our wind turbines is 8m/s, 18mph. A lot of wind turbines are rated approx 12m/s, 27mph. Using a 1kW wind turbine as an example, this is what the different wind speeds against rated speeds will produce for you:
1kW rated at 8m/s in a 18mph wind speed will give 1000 watts.
1kW rated at 12m/s in a 18mph wind speed will give around 660 watts.
So as you can see if the wind speed in your area rarely gets to 27mph but does get to 18mph a wind turbine rated at 8m/s will give you nearly twice the power!
Are these prices for real? What's the catch?
Yes, these are real prices! I think you call it 'ethical pricing'! It is a full kit, the only thing you will need apart from this is batteries (we can supply 110Ah deep-cycle batteries for £60), battery hook-up cables and cement for the foundations. These wind turbines are extremely good quality, and I have sold a lot in the UK. Unfortunately, as there are a lot of over-priced wind turbines for sale, it seems too good to be true - so if you do have any doubts, feel free to come and have a look at the turbines before you buy. There is no catch! We provide wind turbines as DIY kits, or we can install them for you. Please contact us for details and costs of our installation service.
Will I only have power when it is windy?
No, wind turbines are used to charge a set of batteries, which we can also supply if required (110Ah deep-cycle batteries are £80). This means power can be generated and stored whenever it is windy and is ready to use as and when you need it. Of course if there is a prolonged period of still weather your batteries will run down and you will have to rely on your standard supply!
What are the dimensions of the turbines?
| Turbine Size | Blade Diameter | Tower Height |
|---|---|---|
| 200W | 2.0 metres | 4.0 metres |
| 300W | 2.5 metres | 6.0 metres |
| 500W | 2.7 metres | 6.0 metres |
| 1kW | 3.0 metres | 6.0 metres |
What power wind turbine do I need to power my house?
Two things determine wind turbine choice:
1. The amount of wind energy available at the site!
2. The amount of energy required!
Both are very difficult to measure. To help determine the amount of wind energy available at your site
we now sell a wireless weather station. You can also check the
average wind speed at your location at the BWEA website. This will give you the wind speed high-up,
where there are no obstacles to cause turbulence. This will NOT tell you how well a wind turbine at low
height will perform. Generally, if you consider the site to be windy, then you will get good results
with our turbines. However, even a distance of a few metres off the ground can make a huge difference
to turbine performance, and it can be quite amazing how significant the disruption caused by trees and
buildings can be. The amount of energy required can be more difficult to determine as it varies from
household to household. We sell an Efergy power meter, which you connect to
your electricity meter, it gives you information on how much energy you are using. This can help you
understand your energy usage and help determine what size wind turbine you should be looking for.
What size turbine should I buy?
There is no easy answer to this question, if we had £10 for every time this question was asked, we would no
longer need to sell them!
The following should give you some useful pointers:
A 200W turbine is capable of running all of the household lighting, in a suitably windy location.
If you have an existing battery system, your decision may be based on the voltage of that system.
How much do you want to spend?
How much space do you have?
Do you want to use "grid-connect" to sell power back to your supplier? Wind turbines make excellent grid-connect power systems. However the cost of the grid-connect equipment is high, making it a long term investment.
To work out what size wind turbine you require, you firstly have to identify your demands (to help you do this we now sell an Efergy power meter). If you average out household demand over 24 hours, most houses use around 500-750watts. However, peak demand can exceed 10kW. If you want to be dependent on wind power, you will need to reduce your peak demand to a level that can be sustained by your inverter. Wind turbines are generally assumed to produce around 30% of their rated power if you average things out - so to provide for a constant load of 500W, you would need a 1.5kW wind turbine. Of course, this assumes no losses at all and any excess can be stored for use when needed.
Wind turbines are not generally connected directly to electrical loads. This is because wind power varies constantly, so the voltage and frequency will constantly be changing. The simplest solution is to use a battery bank plus inverter, however this can't be connected directly to your normal household wiring.
All in all, you get a great energy return on the investment which is very effective for off-grid applications. You could use a grid-connect system, which can be directly interfaced with domestic wiring (i.e. no batteries), basically using the national grid as a battery feeding excess power into it through an export meter. Grid-connection systems are the best way to run your entire house on wind power, but the grid-connect equipment cost can exceed the cost of the wind turbine by some margin and is therefore a longer term investment.
Does your wind turbine produce 1kW per hour or per day?
Don't confuse output power in kW with energy in kWh. The wind turbine power is measured in kW - this means the rate at which it produces renewable energy. If you measure the amount of energy produced by the wind turbine in a given time e.g. in a day, you would do so in kWh (kW hours). So if the turbine ran at full power (2kW) for 4 hours, then it would produced 2kWx4=8kWh of energy. Another example is a 100W light bulb. This uses 0.1kW of power when it is running. If the light was lit for 5hours, then it would use 0.1 x 5hours = 0.5kWh of energy
Do I need planning permission?
Planning requirements vary from one area to another. Most planning departments will require planning consent for structures over 4m high. However, planning should not be required for temporary structures - and many people have successfully argued that a tilt-up tower (as supplied by us), is a temporary structure, as it can be lowered to the ground when not in use. The same applies for mounting the turbine on any kind of movable structure, such as a trailer, light gantry, cherry-picker or forklift. If planning consent is sought, it is normally granted without problems, and we can help with the wording of planning applications, if required. Approximately 95% of customers do not bother with planning permission, and this does not normally cause problems. You can always apply retrospectively, if required to do so. Though for the larger turbines (2kW plus) we would recommend you seek advice from your local planning department.
Where should I site the wind turbine?
The turbine should be sited far enough away from living and sleeping areas so as not to cause disturbance. Consideration should also be given to neighbours in this respect - after all, they will not be reaping the free electricity from the wind turbine! Generally the wind turbine should be at least 7m (for 4m towers) or 8m (for 6m towers) from the house. To ensure safety, the tower should be situated away from buildings, cars and play-areas etc, so that no damage will occur to property if the tower should fall for any reason. You should not allow anyone to come within 7m of the tower whilst the wind turbine is operating, or during windy weather, for safety reasons. Some companies advocate mounting a wind turbine on a rooftop or gable end. This is strongly discouraged by most installers for the following reasons:The vibration will carry through the building structure and exaggerate noise inside the building.
The building structure may be weakened by constant vibration unless using a very small turbine.
Planning consent is much less likely to be granted for roof-mounted turbines.
The turbulence associated with a roof will reduce performance and lifespan.
For best performance, the wind turbine should be mounted in an open position away from trees, buildings or any other structures. The turbine should be mounted as high as practical, and with clear views to the prevailing wind. If possible, the turbine should be located on a hilltop, or ridge on the side exposed to the prevailing winds. Not all locations can provide ideal positions for wind turbines, but even theoretically poor sites can yield adequate results, although you may experience lower outputs.
We recommend you use a wireless weather station to determine where you get the most wind power. Set it up in a few different positions which fulfil the above requirements over the course of a few weeks and this should help indicate which position would yield the most power. Decisions like this should not be rushed.
Wind turbines are not silent, but nor are conventional power sources (think of petrol or diesel generators!). The wind turbines make a swishing noise, caused by turbulence around the blades. This is not particularly loud, and often the noise of the wind itself and of trees buffeting in the wind is louder. However, in strong winds, the turbine can create a whistling noise - so it is not a good idea to site it immediately next to the bedroom window, however, with double-glazing, it is unlikely that you will hear the turbine inside a building 10metres away.
The survival wind speed (40m/s) seems low?
Actually this is quite fast - it is equivalent to 90mph. This is the highest inland wind speed ever recorded in the UK. However most wind turbine failures are caused by gusts rather than constant high speed wind - often gusts will be far faster than the measured wind speed, and often come from a completely different direction. For customers in very windy areas-particularly on the coast in exposed locations - may consider this survival speed too low. In such circumstances, it is possible to trim the blades to a shorter length, which will reduce their performance in low wind speeds, but it will allow the turbine to withstand higher wind speeds without damage. It is important to bear in mind that these turbines are low-wind speed turbines, which in average UK winds, outperform wind turbines from another British manufacturer rated at 4 times higher power!
Can I get a grant for these systems?
In order to get approval for the government's so-called grant scheme, it is a necessary for us to spend £10,000+ getting the wind turbines approved. If we do this, the price of the wind turbines would have to be increased substantially to cover the cost of this approval. When the government have issued little more than 200 grants in total, it seems that these grants are not that readily available! DIY installations are specifically excluded by the grant scheme, so you would be looking at spending £15,000+ to qualify for a wind turbine grant!
Can I connect the wind turbine to the grid to sell the electricity?
The wind turbines producing less than 1kW of power are low-voltage machines, designed for charging 24v-48v battery banks. You will need a 'grid tie inverter' to feed electricity into the mains supply. These are special inverters that must meet the requirements set out in the G83 electrical standard. However, grid-tie inverters are usually designed for input voltages of 200-600v, so most are not suitable for this application. There are a few available, for example Phillips can provide suitable equipment which accepts low voltage input.
How much maintenance do the systems require?
The wind turbines are very reliable. No strict maintenance is necessary, but the turbine blades should be checked regularly for damage, and to ensure that they are in balance, and the structural parts (tower, guy wires, anchors etc) should be checked for damage, cracks etc.
Yes, spares are available for these machines. The turbines are very reliable, so it is unlikely you will need spares, unless a mistake is made during installation.
Does the system need to be inspected or installed by a qualified electrician?
As these are low voltage systems, you do not need to get an electrician to install or commission the system. However, if you plan to connect anything to your household wiring system, you should always consult a qualified electrician.
What is the best way to utilise wind power?
Wind power is not a guaranteed constant source of energy, generally the best options
to use the generated power are:
1. Store the power in batteries, for use when needed.
2. Use the power to provide heating (especially useful as houses lose heat faster in windy weather).
3. Sell the electricity directly to the grid, and buy it back when required.
Battery storage is the easiest way to utilise wind power. Although our kits are not
supplied with charge controllers, we can supply them if required.
These will ensure you do not over charge your batteries.
Any type of lead acid battery can be used, but the best batteries to use are
'deep cycle batteries'. Unlike car batteries, these are designed to withstand
deep discharge without damage. They are made with much thicker and heavier
lead plates, which are more resistant to damage, and last many times longer than
conventional lead acid batteries. Deep cycle batteries are also used for forklifts
and leisure batteries. We can supply suitable deep cycle batteries at excellent
prices, please ask us for details.
Don't be tempted to buy gel cell batteries. These are good batteries,
but not very suitable for renewable energy use. This is because gel cells
are designed to be charged carefully, and within strict limitations.
The variable nature of wind turbine energy makes them unsuitable for this application.
The smaller wind turbines are designed for 24v usage. The 500W turbine is
designed for 36v and the 1kW for 48v. You therefore need to use the appropriate
number of 12v deep cycle batteries connected in series i.e. 2x12v for 24v
operation, 3x12v for 36v or 4x12v for 48v. If you need higher capacity, you
can make up additional banks of batteries and put these in parallel - see
diagram below:
What is the recommended system voltage and wattage, and why?
It is a matter of personal preference, and there are many variables
that affect this decision. Often it is necessary to choose a wind turbine
that has to integrate into an existing system - e.g. photovoltaics,
an existing battery bank or a DC backup system. In this case, your choice of
turbine will be determined to some extent by the existing system voltage.
If you are not constrained by this, you need to work out how much power you
require, and how much power is available. Wind power varies enormously from
one site to another, and even at different locations on the same site, but as
a general rule, in a good location you will expect about 30% of the maximum output
when you average out over the whole year. You can expect proportionately more power
during the winter months, and periods of bad weather.
Incidentally, it is possible to boost the performance of the wind turbine in very
low wind conditions by using it will a smaller battery bank than intended. For
example, if you use a 500W 36v turbine to charge 24v batteries, then the power
curve will be shifted towards lower wind speeds, but with a penalty of having
a lower maximum output. One customer reported that his WindPowerUK 500W turbine
massively exceeded the output of a Proven 2kW turbine in almost all conditions,
when used with a 24v battery.
How do I connect the batteries?
The batteries should be connected in series to produce the required voltage. In other words, if you wish to make up a 36v battery bank using three 12v batteries, you should connect the negative terminal of battery '1' to the positive terminal of battery '2' and the negative terminal of battery '2' to the positive terminal of battery '3'. The charge controller output should then be connected to the positive terminal of battery '1' and the negative terminal of battery '3'.
Where can I get the cables for the batteries?
Battery cable can be made up from sufficiently thick copper cable, short lengths of steel or brass bar with battery clamps attached, or if you have screw terminals, you can make connectors from steel plate with appropriately drilled holes. It is also possible to purchase battery cable from battery or renewable energy suppliers, but expect to pay a high price!
Can I use the 200W/300W wind turbine with 12v (1000W turbine on 24v)?
Yes, you can use any of the wind turbines that I sell on 24v or 12v systems. This will mean that the maximum power output is much reduced as the battery will act as a brake. For example, if you use the 500W (36v) turbine with 12 volt systems expect 1/3 of the power, so around 180Watts max, on a 24 volt system the same machine will produce about 365 Watts max. On the other hand your cut in speed is much reduced. If you were to use a 200 Watt (24v) wind turbine on a 12v system, its cut in speed will be reduced from around 4.5m/s to around 2.5m/s and on low wind sites, you will get much more power out of it over a week. You have to obtain a new voltage regulator to prevent over-charging of the battery.
****note: 12v versions of the 200W/300W turbines now available****
How do I tell how much charge is in my batteries?
The state-of-charge of a lead-acid battery can, to a certain extent, be estimated by measuring the open terminal voltage. Prior to measuring, the battery must have rested for 4-8 hours after charge or discharge and reside at room temperature. A cold battery would show slightly higher voltages and a hot battery would be lower. Plate additions of calcium and antimony will also vary the open terminal voltage. Furthermore, AGM has a higher voltage plateau than the flooded lead acid.
| Open Circuit Voltage | State of Charge |
|---|---|
| 12.65v | 100% |
| 12.45v | 75% |
| 12.24v | 50% |
| 12.06v | 25% |
| 11.89v | 0% |
Why does my inverter shut down unexpectedly?
This can be for two possible reasons - either the inverter is overloaded, or the voltage is too low (due to battery voltage too low, poor battery connections or insufficiently heavy battery cable). The inverter shuts down before the batteries are completely discharged to protect the battery from damage.
Should I balance the blades before use?
Yes. Balancing the blades will result in trouble free running, smoother operation with less vibration and longer bearing life.
This is actually quite simple. With the turbine in its normal position, and stationary, blades and hub attached, simply place a weight onto one of the blades extended horizontally from the hub. Start with the weight next to the hub, and gradually move it outwards until the blade starts to turn. Measure the minimum distance required to start turning. Repeat with each blade. If all the measurements are the same, then the blades are balanced. If however, one blade requires the weight to be further out, it means that this blade is lighter, and therefore more weight must be added. You can do this by sandwiching lead plates between the blades and the retaining plates.
Do I need to protect my turbine from lightning?
In many areas, this is not a real threat, however wind turbine towers should be properly grounded or induced current from a nearby lightning strike could damage the associated electronics. Generally, the metal components of the tower and turbine should be grounded to one or more ground rods near the tower base. Very tall towers should have a ground rod at the base plus an additional ground rod at each guy anchor, with all guy wires that connect to that anchor bonded together.
