Wind Turbines For Battery Charging And Auxiliary Power

What Is A Wind Turbine And How Does It Work?

Smaller wind turbines are typically used for applications such as battery charging for auxiliary power for small buildings, boats or caravans, and to power traffic warning signs. They can serve well in an emergency situation where the main power grid fails. Larger turbines can contribute to a domestic power supply while selling unused power back to the utility supplier via the electrical grid. Wind turbines are manufactured in a wide range of sizes, with either horizontal or vertical axes.

Home wind turbines provide a way to independently generate power from the wind to charge batteries. They typically contain three blades and use the wind to create electricity. Some wind turbines can be used with solar panels to generate even more power.

Home wind turbines can be installed and static, or they can be portable. Wind turbines are suitable for both land and marine applications. The best wind turbine for your situation depends on its intended use as well as which features matter most for your applications.

Unlike a stand alone solar panel system, a wind turbine or hydro power hybrid system requires a specific charge controller called a Wind Solar Hybrid Charge Controller and sometimes a piece of equipment referred to as a dump load device to avoid excessive power damage to the wind turbine and hydro power systems. Most newer wind turbines can sense the battery charge state and disconnect from a fully charged battery without using a dump load device.

What To Consider When Choosing The Best Home Wind Turbine

There are many factors to consider when choosing the best residential wind turbine, including the number of blades, material, height, wind-speed rating, and energy output. The following are all the factors to consider before making a decision.

Local Zoning Laws And Height Restrictions - There are a few factors that affect where a wind turbine is placed. Some zoning laws require that the turbine be no more than 500 feet high. Wind turbines also need to be placed at a minimum height of 25 feet to catch the maximum amount of wind and provide the greatest number of benefits. Some turbines may be able to attach to a roof. For both maximizing wind volume and abiding by local regulations, the placement really depends on where the property is located and whether the community has any restrictions. Check with the local zoning laws or the homeowners association to see what is allowed.

Wind In The Area - The amount of wind in the area is an essential consideration when purchasing a wind turbine. Some wind, of course, is desired. However, there is such a thing as too much wind. Before purchasing a turbine, always look for the "wind survival" speed and know how fast winds can be in the area. Some turbines can only handle winds up to 90 mph. Areas that are at risk for hurricanes and tornadoes are generally not good areas for turbines, as winds from these storms can reach up to and over 100 miles per hour. Tornadoes can have wind speeds of up to 300 miles per hour, which is much higher than a wind turbine can accommodate. Very high winds like these can remove the turbine and endanger surrounding property.

Blades - Different wind turbines have varying numbers of blades. Three blades is standard, but turbines can have only one blade, four blades, or even more. Two blades are very energy efficient, so having more blades is not necessarily better. Wind turbine blades can be made of different materials. In the past, wood was the chief material used to make wind turbines. Today, fiberglass-reinforced polyester, carbon fiber, and reinforced epoxy materials are more popular, as these materials allow the turbine to spin faster and capture winds at lower speeds. However, since these materials are challenging to recycle, newer materials such as bio-based composites like flax, hemp, and wood are being tested to solve the problem of recycling blades when they are at the end of their life.

Wind-Speed Rating - Every wind turbine has a wind-speed rating which is measured by an anemometer. This is the speed at which the turbine will produce the optimum amount of power. Some wind turbines are designed to automatically shut off when wind speeds get too high.

Wind speeds for turbines can be categorized by:

• Cut-in wind speed (also called starting wind speed): When the blades start rotating and generating power, generally between wind speeds of 6 to 9 miles per hour, this is cut-in wind speed.

• Rated wind speed: This is when the turbine is producing its maximum amount of power. Even if winds become higher, the turbine will not be able to produce more power than this limit.

• Safe wind speed: The speed that turbines can safely operate, which is usually between 8 and 55 miles per hour.

• Maximum wind speed: Turbines have a maximum wind speed, which is the wind speed they can tolerate before they risk being damaged.

Energy Output - Different wind turbines have different energy outputs, which depend on the blade material and size, and the level of wind speeds the turbine can accommodate before having to shut off. Therefore, a larger turbine with larger blades will be able to capture more energy than a smaller one. The energy output is typically rated in watts. Most turbines do not operate near their maximum capacity for energy output, with typical outputs of 30 to 40 percent their capacity. However, even at this percentage, wind turbines can produce many megawatt hours of energy. A megawatt hour of energy is equivalent to 1,000 kilowatts of energy produced per hour.

Weight - If the plan is to mount the wind turbine on the roof, going with a lighter model may be best. However, if using a pole to support the turbine, the weight may not matter as much. Today's wind turbines are typically made with composite materials that are lighter and therefore give users more flexibility with mounting the turbine. Depending on the size and energy output of the turbine, it can weigh several hundred pounds when mounted on a pole. However, residential wind turbines typically only weigh up to 60 pounds, with some weighing only 25 pounds and portable options as few as 3 pounds. Smaller options are great for those looking for the best small wind turbine.

Material - Most wind turbines today are made with composite, lightweight materials. However, they can also be made out of plastic, metal, steel, or fiberglass. Iron and cast-iron components can be used as well, although they are not typically found on home wind turbines. More eco-friendly materials, such as plant-based composites, are currently undergoing testing as wind turbine components. This includes the blades, which can help prevent these components from ending up in landfills, as many reinforced composites cannot be recycled.

Additional Features - Certain wind turbines come with kits that include everything the user needs to get started. Some turbines come with mounting equipment, such as poles, while others will not. Turbines can also come with a controller that provides remote access to the device. Other turbines are waterproof-rated to ensure they can perform marine applications with anti-corrosion features. What additional features to choose depends on the user's goals for their turbine.

Our Best Choice - ECO-WORTHY Hybrid Solar Wind System Kit
After reviewing numerous options for the best home wind turbine and panel system evaluated based on various typical home needs, we like the ECO-WORTHY Hybrid Solar Wind System Kit which includes a 400W wind turbine, 100w to 600w solar panels, inverter, battery, diversion load (or dump load), and everything you need to install a working wind turbine or hybrid system. It works fine for a cabin, house, or barn that sits at a windy location. If the wind where you live reaches over 10mph, this system will be a very good choice for a starter and expandable wind turbine system - and affordable for the typical rural home owner.

Note: With all the wind turbines to consider, it is essential to know what you would like to power and what features are important to you (such as anti-corrosion blades) when choosing the best wind turbine. For those on a tighter budget, a budget-friendly wind turbine generator kit is a good start.

How To Chose The Best Home Wind Turbines - Chose the best wind turbines based on extensive product research as well as evaluating each model's features, including waterproof ratings, assembly, price, and additional options such as MPPT charge controllers and kits that include mounting equipment or solar panels.

One of the biggest advantages of owning a home wind turbine is a backup power source should the primary one fail. another advantage is the ability to produce power without increasing carbon emissions or adding to a home's energy bills. Since it generates electricity without cost, a wind turbine can pay for itself over time.

Having a more sustainable, renewable energy option has become a priority for many who want to increase their self-reliance and reduce their energy bills. However, a smaller wind turbine can also be the ideal travel companion when camping, traveling in an RV, or living off-grid.

Important Note About Wind And Hydro Power Systems - Unlike solar panel systems, both wind turbine and hydro power systems require an additional piece of equipment referred to as a dump load device to avoid excessive power damage to the wind turbine and hydro power systems.

Wind And Hydro Power Dump And Diversion Loads

Wind energy Dump Load, also known as a diversion load or dummy load, is commonly used in wind and small or microhydro systems to "divert" excess power when the batteries are full in an off-grid system as any excess electrical power generated has no other place to go.

The function of any solar charge controller is to regulate and control the charging of a battery, or batteries, in order to prevent them from overcharging and becoming damaged. The charge controller should disconnect the charging current flow coming from a solar, wind, or hydro power generating device and divert any excess energy to an externally connected secondary connected load, such as a resistance or water heating element. Then basically, a dump load is where the extra unwanted power is sent.

Why Is A Dump Load Necessary?
With a photovoltaic solar system, when the storage batteries are fully charged, the charge controller can simply disconnect the PV panels preventing any further charging current from damaging the batteries. Another reason to take note of a photovoltaic panels open-circuit voltage, VOC value.

Dump Load Resistance
Wind turbine generators (WTG), either vertical or horizontal, are designed to operate under certain load conditions. So for a stand-alone off-grid wind generator (or a hydro generator), there must be some method of controlling the speed of the electrical machine if the batteries are full and the wind continues to blow. As an electrically connected load keeps the wind turbine generator within its designed operating range.

If a wind turbine generator, (WTG) is allowed to rotate in the wind with the batteries disconnected, it will start spinning at very high speeds because it is operating without any connected load to act as an electrical brake. This overspeed condition can cause mechanical damage to the turbine as it could potentially self destruct.

Also, if the charge controller then decides to reconnect the wind turbine to the batteries once again while it is rotating at high speed, a mechanical shock to the wind turbine can occur due to the sudden decrease in rotational speed. Thus wind turbines are designed to operate under load conditions.

There are three common methods for controlling the rotational speed of a wind turbine generator. (1), mechanically spilling wind from the blades by changing their pitch angle. (2), use a mechanical brake to stop the turbines rotation at high speeds. Or (3), use some kind of electrical load in the form of a dump load to act as an electrical brake. Clearly, No3 is the cheaper option.

For a small off-grid stand-alone generating system, the generated power is subject to the availability of the source, either wind or water. Therefore, any variation in power demand by the user or batteries must be controlled by the charge controller using a resistive load. Then a dump load or diversion load is nothing more than an electrical resistive element that is correctly sized to handle the full generating capacity of a wind (or hydro) energy system.

How Does A Dump Load Work?
In a wind energy system, turbine generators are commonly used to charge batteries or feed the electrical energy back into the utility grid. A dump load charge controller is basically a solid-state voltage sensing device which constantly monitors the terminal voltage of a battery or connected battery bank to determine its state of charge level.

For a single 12.7 volt deep cycle battery, when its terminal voltage reaches approximately 14.4 volts, it is considered "fully charged" so the charge controller senses this voltage level and disconnects the wind turbine preventing overcharging and damage. At the same time, the charge controller switches the wind turbine's output power to the dump load connected to it which keeps the wind turbine generator rotating at a constant rotational speed.

After the battery bank's voltage drops below 12 volts (about 50% capacity), the charge controller senses the voltage drop and reconnects the output supply from the wind turbine generator back to charging the battery. This connecting, disconnecting cycle of both the battery and dump load is repeated as required preventing the battery from overcharging and maintaining the turbine generator always operating under load.

Batteryless grid-tied systems (wind or hydro) will use the connected grid as their dump load, sending all the excess energy back into the utility's grid. For off-grid hydro or micro-hydro turbines, they will still require the means to dump excess energy when the batteries are full or the household loads are reduced.

Dump or diversion loads are a convenient way to divert or shunt excess electrical energy that could otherwise damage a renewable energy system once the batteries are full. A anything that has a resistive element is great as a dump load as they can take a lot of electric power. But as well as large wattage resistances, immersion elements in hot water tanks also make useful dump loads.

Water Heating Element Diversion Load
Resistive dump loads are simple and easy to design but are also somewhat wasteful as they take the excess electricity and convert it into heat which is then dissipated into the surrounding air. Another more useful option is to use the excess electricity to heat water.

Using an ordinary electric water tank, the regular AC powered heating element can be replaced with a special DC (direct current) heating element. Excess power diverted by the charge controller warms the water in the tank, thereby reducing the AC grid power you use.

DC water heating is a relatively new idea as an off-grid way to heat water using hydro or wind power. Insulated water tanks and old electric storage heaters can be used as pre-heating tanks with 12, 24 or 48 volt DC elements as dump loads up to several kilowatts of power. But, any electrical resistance water heater used as a dump load must be electrically sized to handle the full generating capacity of the wind, or microhydro turbine to keep the turbine fully loaded all the time and keep the combined load consistent.

Dump Load Summary
Dump or diversion loads provide a place for excess electrical power to be dumped or diverted away after the batteries are fully charged in an off-grid system. Dump loads such as power resistances, electric water heaters or hot air heaters dissipate any excess power generated by wind or hydro generators otherwise it has no place to go.

In a batteryless grid connected or grid-tied system, the load is the utility grid which is always connected. For a battery-based solar system, charge controllers are required to regulate the charging of the storage batteries. When a photovoltaic panel or array is disconnected from a battery bank or load, it just sits there in the sun not generating power. For wind or microhydro turbines, their rotational speed may increase to the point that they self-destruct or create overvoltage conditions.

Dump or diversion loads can prevent a wind or hydro generator from spinning too fast once the batteries are fully charged due to the charge controller disconnecting the electrical generator from the attached load. Dump or diversion load control by the charge controller always keeps the generating turbine electrically loaded, which in turn controls the turbine's rotational speed.