We frequently receive inquiries regarding why dump loads are required on wind turbines and how to determine the proper dump load(s) for a given system. The first section of this article will discuss why dump loads are utilized on wind turbines, and the second section will go over how to figure out which dump loads will work best for your system.
First and foremost, please notice that the terms “diversion load” and “dump load” are synonymous.
Why is a dump or diversion load necessary?
When running, wind turbines are meant to be loaded. The load on a wind turbine is nearly always an electrical load that draws power from the turbine’s generator. A battery bank and an electrical grid are the two most typical loads for a wind turbine. Although many of you reading this post are probably aware of this, it is critical to realize that an electrical load (such as a battery bank or the electric grid) keeps a wind turbine within its designated operating range.
Let’s use a hand drill on a piece of wood as an example to truly drive this concept home. The hand drill represents a wind turbine, and the wood represents an electrical load in our comparison. If you put the hand drill to its greatest power level and let it spin in the open air, it will probably spin at around 700 rpm. Because the drill isn’t doing any work, this is referred to as a “no load” condition. What will happen if we use the hand drill’s highest power setting to begin drilling a hole in the wood? When compared to spinning in free air, the hand drill’s rpm will definitely slow down significantly. This is due to the fact that the drill now has to work extra hard to bore a hole in the wood. This is what is referred to as a “laden” scenario. A drill, on the other hand, is meant to run on “no load,” whereas a wind turbine is not.
In high wind conditions, a wind turbine that is not loaded can self-destruct. Wind turbine blades can spin so fast under strong winds with no load that they can rip off or, at the at least, exert extreme pressures and strains on the wind turbine components, causing them to wear out quickly. In other words, when a wind turbine is loaded, it runs safely and properly.
Wind turbines are typically utilized to charge battery banks or feed an electrical system, as previously indicated. Both of these applications required dump loads, but let’s take a closer look at the battery bank application.
A wind turbine will keep charging a battery bank until the bank is completely charged. This is around 14 volts for a 12 volt battery bank (The exact fully charged voltage of a 12 volt battery bank depends on the type of batteries being used). Once the battery bank is fully charged, the wind turbine must stop charging it since overcharging batteries is dangerous for a variety of reasons (i.e. battery destruction, risk of explosion, etc.) But wait, there’s a snag! We must maintain an electrical load on the wind turbine! A diversion load charge controller is utilized to perform this purpose.
A diversion load charge controller is essentially a voltage sensor switch. The voltage of the battery bank is constantly monitored by the charge controller. When the voltage level in a 12 volt battery bank hits around 14 volts, the charge controller detects this and disconnects the wind turbine from the battery bank. A voltage sensor switch is a diversion load charge controller, as we previously stated. So, in addition to disconnecting the wind turbine from the battery bank, a diversion load charge controller can also switch the wind turbine’s connection to the diversion load! And the diversion load charge controller performs exactly that, keeping the wind turbine at a steady electrical load.
The charge controller detects a slight reduction in battery bank voltage (about 13.6 volts for a 12 volt battery bank) and turns the wind turbine back to charging the battery bank. This cycle is repeated as needed to prevent the battery bank from overcharging and to keep the wind turbine running.
How do I figure out how many dump loads I need?
Now, in order to determine the proper size of your dump load system, you must first ask yourself the following questions: (1)What is my system’s voltage (12 volt battery bank, 48 volt battery bank, 200 volts?) (2) At full power, how many amps will your wind turbine produce? You can continue on to the next phase after you have this information.
We’ll need to do some math and apply Ohm’s Law in the next few phases. Let’s use a real-life example instead of generalizations. Our Windtura 500 wind turbine will be used to charge a 24 volt battery bank in this demonstration.
26 amps is the answer. (We can see this from the Windtura 500’s reported power curve.)
Step 3: The dump load mechanism must be capable of dumping the wind turbine’s maximum output power. Power equals Volts x Amps, according to Ohm’s law. The voltage of the system is the voltage of the battery bank (We are going to use 29 volts which is roughly the voltage of a fully charged 24 volt battery bank). The current produced by the Windtura 500 at maximum power is measured in amps (26 amps).
Step 4: We’ll need a dump load capable of discharging at least 754 Watts. In this example, we’ll use our 24 volt dump load resistors. The internal resistance of these resistors is 2.9 ohms. We need to determine out how much electricity this resistor will consume, knowing that it is 2.9 ohms.
Using Ohm’s law, Voltage = Current x Resistance, and some basic algebra, we get the following equation:
(Battery bank voltage)/(Resistor’s resistance) = (29 volts)/(2.9 Ohms) = 10 amps Current = (Voltage)/(Resistance) = (Battery bank voltage)/(Resistor’s resistance) = (Battery bank voltage)/(Resistor’s resistance)
Now we know that one of these resistors will draw 10 amps of electricity at 29 volts (battery bank voltage). What is the power consumption of the resistor?
(Battery bank voltage) x (amps through resistor) = (29 volts) x (10 amps) = 290 Watts Power = Volt x Amps = (Battery bank voltage) x (amps through resistor) = (29 volts) x (10 amps) = 290 Watts
As a result, one of our WindyNation 24 volt dump load resistors will be able to handle 290 Watts. Important: Make sure the dump load you’re using is rated to withstand 290 Watts at continuous duty at this point, or there could be a serious fire hazard. The WindyNation 24 volt dump loads can carry up to 320 Watts of continuous power, thus they’ll be perfect for this job.
If you read Step 3 again, you’ll see that our dump load system must be capable of dumping at least 754 Watts. What can we do with a 290 Watt dump load resistor to accomplish this? That’s a piece of cake! The dump load Wattage is cumulative if numerous 290 Watt dump load resistors are wired in parallel. As a result, we have the following simple equation:
Total Watts required for our dump load system = (290 Watts) x (number of 2.9 Ohm resistors required in parallel)
We can’t utilize 2.6 resistors because our resistors only come in whole units. We must round up because we require AT LEAST 754 Watts. As a result, we’ll need to connect three WindyNation 2.9 Ohm resistors in series. This gives us a dump load capacity of 870 Watts. We’ve now put up a dump load system that’s appropriate for the wind turbine and battery bank we’re using in this scenario. Any wind turbine system can benefit from the same conceptual process (Steps 1-6).
We hope that this post has shown why dump loads are required for wind turbines and how to determine how to set one up for your specific system.
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What is the most effective method for charging a lithium-ion battery?
Lithium-ion batteries have two electrodes, one positive and the other negative. When you charge or drain your battery, electrons travel outside the battery via the electrical current, while ions travel from one electrode to the next. It’s as if both electrodes are exchanging ions in and out, as if they’re breathing.
Electrons go from the anode to the cathode outside the battery when the battery delivers current. Reverse current allows the battery to recharge by sending electrons back to the anode and allowing lithium ions to re-intercalate in the cathode. This replenishes the capacity of the battery. A cycle is used to describe the entire charging and discharging operation. The number of cycles your battery may go through is determined on the manufacturing process, chemical components, and actual use.
A rechargeable battery’s capacity is measured in Ah. For example, the Saft MP 176065 xtd has a 5.6 Ah capacity, which implies it can supply 5.6 A in an hour at 25C over a cycle.
- The C rate is the battery’s charging and discharging rate. Typically, charge and discharge currents are stated as fractions or multiples of the C rate: A C charge/discharge indicates that the battery will be charged or discharged in one hour. It takes two hours to charge and discharge a C/2 battery, 30 minutes to charge and discharge a 2C battery, and so on. The MP 176065 xtd C rate of Saft is 5.6A. It would take about 2 hours to charge a C/2 at 2.8A.
- A 4.2V signifies a full charge, whereas a 2.7V indicates the battery is entirely depleted in our MP 176065 xtd example above (cut-off voltage).
- Multiple cycles: the battery loses capacity over time as the electrodes and electrolyte deteriorate physically and chemically.
A competent control of the depth of discharge (DoD the percentage of capacity taken from a fully charged battery) and the maximum charging voltage can also increase the number of cycles the battery can execute and, as a result, its operating life.
This post concentrates on charging best practices; however, we’ll provide discharging best practices in our upcoming article.
Is it possible to link my solar inverter to a wind turbine?
We do not sell 240-volt AC wind generators, but we do offer four other options for you to consider:
- Install a hybrid inverter and battery in place of your present solar inverter, and link the wind turbine to the battery. The cost is approximately $4000, plus the cost of the wind generator.
- Install a Luxpower ESS beside your existing solar inverter while keeping the rest of your solar system the same. Attach a small battery to the ESS and connect the wind turbine to it.
- Connect your solar panels, inverter, and wind generator to the same battery using an existing Latronics PV Edge 1200 inverter.
- Install a Selectronic inverter and battery, with the Selectronic inverter monitoring the wind generator output.
Is it possible to charge a solar generator using a wind turbine?
“Yes, they can, so it isn’t just a fantasy.” Solar panels and wind turbines charging one battery are a good illustration of marine usage. On the internet, you may get kits that charge a single 12V 100Ah deep cycle battery. A system from Eco-Worthy includes a 100-watt solar panel, a 400-watt wind turbine, and a 20-amp hybrid controller. I suppose a modest system like this could be developed for use with a static trailer or a shed.”
What is the time it takes for a wind turbine to charge a battery?
Because every wind turbine installation (even micro turbine installations) has so many variables, this is a challenging question to answer.
When it comes to calculating battery charge times, two primary factors come into play: wind speed and battery size.
This would be equivalent to 0.8 amps if you had a lot of wind and the tiny turbine generates roughly 10W of power (when charging at 12.5V).
0.8 amp-hours would be equivalent to one hour of charging.
If you have a 100 amp-hour battery that is now at 80% charge, you can charge it to 100% in around 24 hours under these conditions.
Because it has a larger generator (33W max), our cyclone turbine would double the power output.
If you’re having difficulties with charge times or voltages, we strongly advise using an anemometer to detect wind speed.
When you use a weather app to report wind speeds, it’s common for it to be erroneous.
Because the anemometer on the weather app is 30-50 feet high at the top of a weather station, with no buildings or trees in sight, this is the case.
When you measure the wind speed yourself, you eliminate a lot of the guesswork.
Is it possible to charge an electric car with a wind turbine?
The worldwide automobile industry is working for the creation of cars that generate fewer or no hazardous pollutants, use alternative fuels, or have regenerative technology, and have low operating costs. This is where electric vehicles enter the picture. Solar-powered vehicles and vehicles with regenerative braking have been among the many advancements (generating energy every time brakes are applied). And the most recent breath of fresh air comes from Colombia, a South American country…
Colombia’s only domestic car is the Eolo. It charges its batteries with an innovative and efficient technology that employs wind energy. It gets its name from the fact that it is the world’s first ‘eolic’ car, which means it is powered entirely by wind.
Minuto de Dios Industrial Corporation The first prototype of an electric automobile that recharges with wind energy was constructed by Javier Roldn, the system’s inventor, and project Eolo designers. The device works on the simple premise of a spinning wind turbine charging batteries, which then power the wheels.
On the front of Eolo are massive horizontal propellers or wind turbines that spin quickly as the car moves, sucking in wind and converting it into electricity to charge the electric car’s batteries.
The turbines are said to contribute up to 10% to Eolo’s total range, and it can be charged overnight using a conventional plug connection. According to the project’s creators, the car has a range of 100 kilometers and a top speed of 100 kilometers per hour.
In Greek mythology, Eolo, or Aeolus in English, was the keeper of the winds, and his name was used to name Roldn’s electric car with horizontal propellers.
While the technology is rudimentary in its current form and may take a long time to mature into a viable contender, it is an important step forward in the development of electric vehicles.
Is it possible to store electricity generated by wind turbines?
The need for solar and wind energy continues to rise around the world. Since 2009, global solar photovoltaic installations have grown at a rate of roughly 40% per year on average, while wind turbine installed capacity has doubled.
Because of the rapid growth of the wind and solar industries, utilities have begun to test large-scale technology capable of storing excess clean electricity and supplying it on demand when sunlight and wind are scarce.
Now, a group of Stanford academics has looked into the “energetic cost” of producing batteries and other grid storage devices. The question is whether renewable energy sources like wind and solar photovoltaics can generate enough energy to support both their own expansion and the growth of the requisite energy storage business.
“Whenever you design a new technology, you have to put a lot of effort into it up front,” said Michael Dale, a Stanford research associate. “Wind turbines and solar photovoltaic systems currently create more energy than they consume, according to studies. The question is how much more grid-scale storage can the wind and solar businesses afford while still remaining net energy producers to the grid.”
Dale and his Stanford colleagues concluded that the wind sector can easily afford a lot more storage, enough to give more than three days of uninterrupted power, in an article published in the journal Energy & Environmental Science on March 19. The study did find, however, that the solar sector can only afford roughly 24 hours of energy storage. This is because solar panels require more energy to build than wind turbines.
“We looked at the additional strain that concurrently building up batteries and other storage technologies will have on the solar and wind industries,” said Dale, the study’s primary author. “Even with a substantial quantity of grid-scale storage, our analysis demonstrates that today’s wind sector is energetically viable. We discovered that by lowering the amount of energy used to manufacture solar photovoltaics, the solar sector can also attain long-term storage capacity.”
Favorable winds
Consumers have come to anticipate electricity on demand from power plants that run on coal, natural gas, or oil throughout the years. However, while fossil fuels provide consistent, round-the-clock electricity, they also generate massive amounts of greenhouse gases, which contribute to global warming.
Wind and solar farms generate electricity when the wind blows or the sun shines, but they only do so when the wind blows or the sun shines. Surplus energy can be saved for later use, but because today’s electrical system has limited storage capacity, additional methods of balancing supply and demand are employed.
The Stanford researchers looked at a number of grid storage solutions, including batteries and geology systems like pumped hydroelectric storage. The findings were quite positive for the wind industry.
“Wind energy technologies produce significantly more energy than they require,” Dale explained. “Our research found that wind generates enough excess energy to enable up to 72 hours of battery or geologic storage. This implies that the sector could deploy enough storage to deal with three-day wind lulls, which are frequent in many weather systems, while still providing net electricity to society.”
Onshore wind turbines fared particularly well in the study. “We discovered that onshore wind with three days of geologic storage may support yearly growth rates of 100% in other words, doubling in size each year while still maintaining an energy surplus,” he stated.
Sally Benson, a professor of energy resources engineering and director of Stanford’s Global Climate and Energy Project (GCEP), remarked, “These results are quite encouraging.” “They demonstrate how combining wind and storage can result in a self-sustaining energy system that expands and maintains itself. This is dependent on the business’s rate of expansion, because the faster the industry expands, the more energy is required to create new turbines and batteries.”
Solar industry
The Stanford researchers discovered that additional work is needed in the solar business to enable grid-scale storage energy-sustainable. According to the research, some solar technologies, such as single-crystal silicon cells, are becoming net energy sinks, meaning they absorb more energy than they give back to the grid. According to the report, these businesses “cannot support any level of storage” from an energy standpoint.
“Our investigation revealed that most photovoltaic technology can only store up to 24 hours of energy with an equal mix of battery and pumped hydropower,” Dale explained. “This shows that solar photovoltaic systems might be deployed with enough storage to provide electricity at night while still allowing the industry to operate at a net energy surplus.”
Benson noted that one advantage of wind over solar power is that it offers a huge energy return on investment. “A wind turbine generates enough electricity to pay for all of the energy it needed to create it in a matter of months,” she remarked. “However, some photovoltaics have a nearly two-year energy payback time. Continued decreases in the quantity of fossil fuel used to make solar cells will be required to sustainably support grid-scale storage.”
Other costs
The Stanford team concentrated on the energy cost of installing storage on wind and solar farms. The researchers did not assess how much energy would be necessary to create and replace grid-scale batteries every few years, nor did they include the financial costs of building and deploying huge grid-scale storage systems.
“Is storage a good or poor answer for intermittent renewable energy?” people frequently ask. Benson remarked. “That question appears to be very simplified. It isn’t nice or terrible in any way. Even if grid-scale storage of wind electricity is not as cost-effective as buying power from the grid, it is energetically cheap, despite the wind industry’s double-digit growth.
“The solar sector must continue to cut the amount of energy required to manufacture photovoltaic panels before it can afford the same amount of storage as wind.”
Charles Barnhart, a postdoctoral scholar at GCEP, was a co-author on the work. The GCEP provided funding for the study.
