Understanding Battery Ah A Guide To Battery Capacity

What is a battery pack?

Battery packs are portable power sources that store electrical energy for later use. They typically consist of multiple battery cells grouped together, allowing them to deliver a higher voltage or capacity than a single cell.

What is the difference between a battery cell and a pack?

A battery cell is a battery's basic unit, whereas a battery module is a collection of battery cells. A pack, on the other hand, consists of one or more modules as well as any other components required for operation, such as enclosure, connectors, and control circuitry. The following comparison chart demonstrates this in greater detail:

What is a battery pack & why do you need one?

Battery packs serve as emergency power sources during outages. They can power essential devices like lights, refrigerators, and communication tools. The Federal Emergency Management Agency (FEMA) recommends having portable battery packs available for emergency preparedness, underscoring their role in ensuring safety and resources during crises.

How does a battery pack work?

When a device is connected, the stored energy is converted back into electrical power. Voltage Regulation: Portable devices require a specific voltage to operate. Battery packs include voltage regulators that adjust the electrical output to match the device's requirements. This ensures optimal performance and prevents damage to the device.

What is a lithium-ion battery pack?

A lithium-ion battery pack is a collection of multiple lithium-ion cells connected together to store and provide electrical energy. These battery packs power various electronic devices, from smartphones to electric vehicles, due to their high energy density and rechargeable nature.

What is a battery cell module pack?

A battery cell module pack is the complete assembly, generally having many modules and several critical components: The pack production lines have to fulfill two functions: assembly and package.

Will Albania build its first lithium ion battery plant?

Chief Executive Officer Bruno Papaj said the firm signed a memorandum of understanding with an Indian investor on the construction of Albania's first lithium ion battery plant. The facility is planned to come online within two years, with 100 MW in annual capacity.

Why does Tirana need Vega Solar?

Furthermore, the country is exposed to drought and often turns to emergency imports. Tirana-based Vega Solar, which develops, installs and maintains rooftop solar power plants, saw an opportunity to contribute to diversification with battery energy storage systems.

Does Albania have a hydropower plant?

Hydropower makes up almost the entire domestic output in Albania, which helps balancing to a point, but it has no pumped storage hydropower plants. Furthermore, the country is exposed to drought and often turns to emergency imports.

How to calculate battery capacity?

Battery Capacity in Ah = (900Wh x 2 Days x 3 Hours) / (50% x 12 Volts) Required Size of Battery Capacity Bank = 999 Ah (Almost 1000Ah) This is the minimum battery bank capacity size you need to run a 900Wh load daily for 3 hours. Related Posts: How to Calculate the Battery Charging Time & Battery Charging Current?

What is the battery calculations workbook?

The Battery Calculations Workbook is a Microsoft Excel based download that has a number of sheets of calculations around the theme of batteries. Note: The calculations in this workbook are for Indication only. All data and results need to be subject to your own review and checks before use.

How to calculate battery usage?

First of all, you will have to calculate the total amount of loads in watts which is needed to run directly or later on the storage energy in the batteries. If it is home based, you may easily get annual power usage data from the energy meter or electricity bill.

How to calculate size of battery bank & inverter?

Calculate size of battery bank and inverter This MS Excel spreadsheet calculates the following parameters: Total Demand Load Size of Battery Bank in Amp.Hr. Select Type of Connection of Batteries in Battery Bank Select Rating of Each Battery in Battery Bank Size of Inverter Size/Type/Tripping setting of Main MCCB. Software:

How to calculate a battery load?

Step 1: Collect the Total Connected Loads The first step is the determination of the total connected loads that the battery needs to supply. This is mostly particular to the battery application like UPS system or solar PV system. Step 2: Develop the Load Profile

How do you determine a battery's ampere-hour (Ah) capacity?

To determine a battery's Ampere-Hour (Ah) capacity, we first need to know its voltage (V) and the energy it stores (Wh, Watt-Hours). The relationship between a battery's stored energy, its voltage, and its capacity can be expressed using the following formula: E = V ×Q E = V × Q Where: Q Q is the battery's capacity, measured in Ampere-Hours (Ah).

Who sanctioned battery energy storage systems in Georgia?

The systems are sanctioned by the Georgia Public Service Commission through the Integrated Resource Plan. Credit: Georgia Power. US-based electric utility Georgia Power has commenced construction of new battery energy storage systems (BESS) across the state of Georgia, totalling 765MW capacity.

What is Georgia Power's 530-megawatt battery storage system?

Georgia Power breaks ground at the McGrau Ford Battery Facility in Cherokee County on April 4, 2025. This 530-megawatt battery energy storage system will consist of two phases, approved in the 2022 Integrated Resource Plan (IRP) and 2023 IRP Update. Courtesy: Georgia Power.

What does battery mean according to Georgia law?

According to Georgia Code 16-5-23.1, battery is defined as making physical contact of a provoking or insulting nature against someone else, or intentionally causing visible bodily harm to the victim. A person commits battery under this law.

What does Georgia Power do?

Georgia Power senior vice-president and senior production officer Rick Anderson said: “At Georgia Power, we work with the Georgia PSC and many other stakeholders to make the investments required for a reliable and resilient power grid, integrating new technologies to better serve our customers today and as Georgia grows.

Where is Georgia Power's first grid-connected Bess system located?

In February 2024, Georgia Power installed its first grid-connected BESS, the Mossy Branch Energy Facility, a 65 MW system on a couple of acres of rural countryside in Talbot County, north of Columbus, GA. It was approved as part of Georgia Power's 2019 IRP.

Is Georgia Power a source of emission-free energy?

Georgia Power's fleet of hydroelectric generating units is another source of emission-free energy, with some units serving the state of Georgia for more than 100 years.

Which Emirates have a battery energy storage system?

Abu Dhabi, the capital emirates of the United Arab Emirates (UAE). Image: Wadiia / WikiCommons. The UAE should deploy 300MW/300MWh of battery energy storage system (BESS) capacity in the next three years, according to one of its main utilities EWEC.

What are the future capacity requirements for battery energy storage system?

The recommendation was made in the 'Statement of Future Capacity Requirements 2023-2029: Summary Report' by Emirates Water and Electricity Company (EWEC), the utility for the capital emirate of Abu Dhabi. The UAE should deploy 300MW/300MWh of battery energy storage system (BESS) capacity in the next three years, according to utility EWEC.

Why is energy storage important in Dubai?

“We follow the vision and directives of His Highness Sheikh Mohammed bin Rashid Al Maktoum, Vice President and Prime Minister of the UAE and Ruler of Dubai, to ensure energy security and sustainability. Energy storage is a vital aspect in ensuring energy sustainability and increasing the reliance on clean and renewable energy sources.

What is thermal energy storage battery storage project?

The thermal energy storage battery storage project uses molten salt thermal storage storage technology. The project was announced in 2018 and will be commissioned in 2030. The project is owned by Shanghai Electric Group; Acwa Power and developed by Abengoa. 2. Mohammed Bin Rashid Al Maktoum Solar Thermal Power Plant – Thermal Energy Storage System

What is the power capacity of Dewa solar park?

The project has a power capacity of 1.21 MW and an energy capacity of 8.61 MWh with a life span of up to 10 years. This is the second battery energy storage pilot project by DEWA at the solar park.

What is Dubai Electricity & Water Authority (DEWA)?

Dubai Electricity and Water Authority (DEWA) is one of the leading organisations in adopting the latest and best technologies for storing clean energy, and several of its energy storage projects are among the largest regionally and globally.

Can a scalable battery system reduce peak loads?

Currently, a scalable battery system with 60 kWh storage capacity reduces peak loads in the institute network by about 10%. The usual operating procedures have not been and will not be affected by this. The results of the research work can be applied to industrial or commercial energy systems with large electrical load peaks.

How can a battery energy storage system improve battery life?

Self-consumption and oversized photovoltaic integration with batteries is analyzed. Peak shaving level is optimized for each strategy, maximizing monthly savings. Battery lifetime analysis emphasizes the strategies' impact on battery degradation. Battery energy storage systems can address energy security and stability challenges during peak loads.

Can energy storage reduce peak load?

Both the efficient intermediate storage of large amounts of energy and the delivery of high outputs had to be ensured. The result: an energy storage system of around 350 kWh would enable peak load reductions of around 40% since many of the peak loads only occur for a very short time.

What is a battery storage system?

The solution is an intelligently controlled battery system with which the financial potential of peak load reduction can be exploited without affecting the production process. In principle, the battery storage unit is charged at low power levels and discharged at times of high power levels.

Does peak shaving a battery save money?

According to the results obtained in this study, more than the economic savings achieved by the peak shaving operation of the storage system is needed to compensate for the battery investment, considering the typical costs of industrial battery storage.

Why are electric battery storage systems becoming more profitable?

Technological advances and falling prices are now enabling the profitable use of electric battery storage systems. As a result, electrical load peaks on the consumer side can be reduced without having to intervene in production processes.

What is depth of discharge in a battery?

Depth of discharge (DoD) in batteries is the percentage of the battery's overall capacity that has been discharged, calculated by dividing the capacity discharged from a fully charged battery by its nominal capacity.

How long can a battery be discharged?

Maximum 30-sec Discharge Pulse Current –The maximum current at which the battery can be discharged for pulses of up to 30 seconds. This limit is usually defined by the battery manufacturer in order to prevent excessive discharge rates that would damage the battery or reduce its capacity.

How do you calculate battery discharge rate?

In this case, the discharge rate is given by the battery capacity (in Ah) divided by the number of hours it takes to charge/discharge the battery. For example, a battery capacity of 500 Ah that is theoretically discharged to its cut-off voltage in 20 hours will have a discharge rate of 500 Ah/20 h = 25 A.

What is a rated battery capacity?

Manufacturers specify the capacity of a battery at a specified discharge rate. For example, a battery might be rated at 100 A·h when discharged at a rate that will fully discharge the battery in 20 hours (at 5 amperes for this example). If discharged at a faster rate the delivered capacity is less.

How does depth of discharge affect battery performance?

Depth of discharge, denoting the proportion of a battery's capacity that has been utilized, is a key factor influencing battery performance. A high DOD allows for more of the battery's energy to be used before needing to be recharged, but it can also reduce the number of recharge cycles of the battery.

What is battery capacity?

Available Capacity – this is the capacity that can be accessed taking into account the temperature, age, health and use of the cell. Battery capacity is expressed in ampere-hours. Battery capacity is effected by: Discharge rate – normally the higher the discharge rate the lower the capacity.

Does Ireland have a battery energy storage system?

Ireland's ESB has opened a battery energy storage system at its Poolberg site in Dublin. Operational since November, the battery plant is capable of providing 75 MW of energy for two hours to Ireland's electricity system. It features high-capacity batteries that store excess renewable energy for discharge when required.

What will ESB's new battery plant do for Ireland?

ESB, the state-owned electricity company, has announced the opening of a major battery plant at its site in Poolbeg, Dublin. The battery plant will add around 75MW of fast-acting energy storage to make the grid in Ireland more stable and increase the share of renewables in the electricity system.

Will a new battery plant support Irish grid stability?

In a bid to support Irish grid stability, Electricity Supply Board (ESB) has opened a major battery plant at its Poolbeg site in Dublin, which will add 75MW/150MWh of fast-acting energy storage.

Which ESB site is the largest in Ireland?

According to the Dublin-based, state-owned energy company, the battery energy storage system (BESS) is currently the largest site of its kind in commercial operation in Ireland. The site is the latest in ESB's project pipeline, consisting of sites in Dublin and Cork, representing an investment of up to €300 million ($323 million).

Is ESB launching a 75 mw/150 MWh battery plant in Ireland?

ESB has opened a 75 MW/150 MWh battery plant, touted as the largest of its kind in commercial operation in Ireland. Eamon Ryan, the country's Minister for the Environment, Climate and Communications, has said that the site will be a core part of Ireland's renewable energy transition.

How much energy will ESB provide to Ireland's Electricity System?

Image: Fennell Photography Operational since November last year, the project has the capacity to provide 75MW of energy to Ireland's electricity system for around two hours. ESB, the state-owned electricity company, has announced the opening of a major battery plant at its site in Poolbeg, Dublin.

What voltage should a battery be charged at?

If the battery is charged with a low current and a large current, it will heat up quickly and damage the battery. If you want to prolong the life, you can charge it at 0.3C. Higher (15C) charge and discharge current, suitable for use as a power battery. The current used to charge a battery could have an effect on its lifetime.

Why is amperage important when charging a battery?

Amperage is the measure of electrical current, and it is critical to understand when charging a battery. A higher amperage will result in a cooler, steady power supply and shorter charge time, while a lower amperage can cause the charger to overheat.

What is a good charging current for a car battery?

Most automotive batteries recommend a charging current of between 10% to 20% of their capacity. For instance, a 60 Ah battery typically charges at 6 to 12 A. Adhering to these rates prevents overheating and extends battery lifespan. Monitoring battery temperature during charging helps prevent overheating.

How to choose a battery charger?

When it comes to current, you must make sure that the Amps rating is greater than the device requires since it will only consume as much power as is needed. It is best to avoid a charger that is supplying too low amperage.

How does battery size affect charging amperage?

Battery size impacts the required charging amperage significantly. A larger battery has a greater capacity to store energy, measured in amp-hours (Ah). This means it can accept a higher charging current without causing damage or reducing lifespan.

What happens if a battery is fully charged?

The charging current of the battery will decrease, and the battery charging current will decrease as it approaches full capacity until the battery is fully charged. Another is that there is no harm in charging a fully charged battery because the current will be very small.

What is a high capacity industrial lead-carbon battery?

High capacity industrial lead-carbon batteries are designed and manufactured. The structure and production process of positive grid are optimized. Cycle life is related to positive plate performance. Electrochemical energy storage is a vital component of the renewable energy power generating system, and it helps to build a low-carbon society.

Are lead carbon batteries better than lab batteries?

Lead carbon batteries (LCBs) offer exceptional performance at the high-rate partial state of charge (HRPSoC) and higher charge acceptance than LAB, making them promising for hybrid electric vehicles and stationary energy storage applications.

What is a lead battery energy storage system?

A lead battery energy storage system was developed by Xtreme Power Inc. An energy storage system of ultrabatteries is installed at Lyon Station Pennsylvania for frequency-regulation applications (Fig. 14 d). This system has a total power capability of 36 MW with a 3 MW power that can be exchanged during input or output.

What are the advantages of lead-carbon batteries?

Lead–carbon batteries, as a mature battery technology, possess advantages such as low cost, high performance, and long lifespan, leading to their widespread application in energy storage and power battery fields 1, 2.

What is the recycling efficiency of lead-carbon batteries?

The recycling efficiency of lead-carbon batteries is 98 %, and the recycling process complies with all environmental and other standards. Deep discharge capability is also required for the lead-carbon battery for energy storage, although the depth of discharge has a significant impact on the lead-carbon battery's positive plate failure.

Are lead-acid batteries a good energy storage option?

As a result, lead-acid batteries provide a dependable and cost-effective energy storage option , , , , , . Because of the high relative atomic mass of lead (207), which is one of the densest natural products, lead-acid batteries have low specific energy (Wh /kg).

What is battery capacity loss?

Capacity loss can be defined as an irreversible loss of the ability of the battery to store charge . A higher internal resistance reduces the efficiency of the cell, which leads to less usable energy being available and more heat being generated.

What causes a battery to lose capacity?

There are several reasons for this capacity loss. Linear battery capacity fade develops in a straight line with use, and this is the commonest cause. A small amount of this happens each time we charge a battery, and lose a few ions in the process. This stress is most severe if a deep discharge precedes it.

What causes capacity loss during storage?

The available capacity loss during storage that refers to the L a discussed above is mainly caused by the violent and electrolyte-sensitive corrosion of anode, which occupies 72.7% of proportions on average.

Should battery capacity be increased in a worst-case scenario?

Another study from 'Fraunhofer' predicts that the installed battery capacity has to be increased up to 400 GWh in a worst-case scenario . Here, the storage capacity has to be eight times higher, since the consumers are not willing to change their behaviour. Therefore, more energy has to be time-shifted.

Do operating strategy and temperature affect battery degradation?

The impact of operating strategy and temperature in different grid applications Degradation of an existing battery energy storage system (7.2 MW/7.12 MWh) modelled. Large spatial temperature gradients lead to differences in battery pack degradation. Day-ahead and intraday market applications result in fast battery degradation.

Where is the battery energy storage system located?

The battery energy storage system, which is going to be analysed is located in Herdecke, Germany . It was built and is serviced by B e lectric. The nominal capacity of the BESS is 7.12 MWh, delivered by 552 single battery packs, which each have a capacity of 12.9 kWh from Deutsche Accumotive.

What size battery do I need for a 3000 watt inverter?

In my experience, you will need a very minimum of 300Ah battery capacity with a 3000 watt inverter. Now you know how to calculate inverter runtime you can decide what size battery you need. It is likely you will need multiple batteries to give you enough energy for a 3000 watt inverter.

How to calculate battery size for inverter?

Start by assessing your daily power consumption which helps to calculate battery size for inverter. Make a list of all the appliances and devices you want to run on your inverter system. For each item, note the power rating (in watts) and how long you use it each day. Example: LED Light Bulb: 10 watts, used for 5 hours/day

What size inverter for a 200Ah battery?

To determine the appropriate inverter size for a 200Ah battery, consider the following: A 500VA inverter would be suitable, offering a balance between performance and battery life. For extended run times, consider larger inverters or additional batteries to meet higher power demands.

How many batteries do I need for a 12V inverter?

Ensure the configuration matches your inverter system's specifications. Example: If you need 658 Ah at 12V and choose 12V, 200 Ah batteries, you would need: 658 Ah/ 200 Ah per battery ≈ 3.29 batteries Round up to 4 batteries, but keep in mind that over-sizing can be more efficient in some cases.

How much power does a 3000 watt inverter provide?

First, let's address the inverter's continuous power output. A 3000 watt inverter can provide a maximum continuous power output of 3000 watts. However, it is important to note that this is the peak power rating, and the actual power consumption of your appliances and devices may be lower. Next, consider the desired running time for your inverter.

How many hours can a 3000-watt inverter run?

Let's suppose you have a 3000-watt inverter with an 85% efficiency rate and your daily runtime is about 5 hours using a 24v solar system Now to cover watt losses when converting DC to AC You would need around 24v 150Ah Lithium or 24v 300Ah Lead-acid Battery to run a 3000-watt inverter for 1 hour at its full capacity

How to monitor battery status in Arduino IoT based battery monitoring system?

In this IoT-based Battery Monitoring System, we will use the NodeMCU ESP8266 board to send the battery status data to the Arduino IoT cloud. The IoT Cloud Dashboard will display the battery voltage along with the battery percentage in both the charging and discharging conditions.

What is a battery voltage status monitor circuit using 4 LEDs?

The proposed battery voltage status monitor circuit using 4 LEDs makes use of comparators in the form of opamps from the IC LM324. This IC is much versatile than the other opamp counterparts due to its higher voltage tolerance level and due to the quad opamps in one package.

How to set up battery status indicator circuit?

How to Set up the above explained battery status indicator Circuit. It's pretty simple. Apply the full-charge voltage level across the point indicated "to battery positive" and ground. Now adjust the preset such that the last LED just illuminates at that voltage level. Done! Your circuit is all set now.

How does a battery monitoring system work?

This allows users to monitor the battery status remotely from anywhere in the world via their smartphones or computer dashboards. The server displays the battery voltage, load voltage, current, and power, providing a comprehensive overview of the battery's condition in both charging and discharging states.

Why is it important to monitor the voltage level of a battery?

Battery is the most important component for any device as it powers the whole system. And it is important to monitor the voltage level of the battery as improper charging and discharging of a lithium battery may lead to a big safety issue.

How IoT-based battery monitoring system works?

In this IoT-based Battery Monitoring System, we will use Wemos D1 Mini with ESP8266 Chip to send the battery status data to ThingSpeak cloud. The Thingspeak will display the battery voltage along with the battery percentage in both the charging and discharging cases.

How do lead acid batteries recharge?

Lead acid batteries recharge in various manners based on their function and manner of installation. For a lead acid vehicle battery, drive the vehicle around for at least 20 minutes. For a lead acid battery connected to solar panels, let the battery charge fully on a sunny day.

How do you check a lead acid battery?

Fortunately, you can easily do a basic health checkup on any type of lead acid battery by hooking it up to a simple-to-use digital voltmeter. If you have an open-cell battery that lets you access the liquid inside, you can do a more rigorous checkup with a battery hydrometer. Charge the battery fully, then let it rest for 4 hours.

Do lead acid batteries go bad?

The liquid-filled lead acid batteries used in automobiles and a range of other products have many great qualities, but are also known to “go bad” with little warning. Fortunately, you can easily do a basic health checkup on any type of lead acid battery by hooking it up to a simple-to-use digital voltmeter.

What is a lead-acid battery?

Lead-acid batteries are a type of rechargeable battery that uses lead and lead oxide electrodes submerged in an electrolyte solution of sulfuric acid and water. They are commonly used in vehicles, backup power supplies, and other applications that require a reliable and long-lasting source of energy.

How do you know if a lead-acid battery is healthy?

To get a more accurate reading of a lead-acid battery's health, you can use a hydrometer. This tool measures the specific gravity of the electrolyte solution within the battery, which can give you a better idea of its state of charge and overall condition. Before using a hydrometer, it's important to make sure the battery is fully charged.

Can you test a lead acid battery with a hydrometer?

Checking an open-cell lead acid battery—that is, a lead acid battery with caps that can be opened to access the liquid inside—with a battery hydrometer is most accurate when the battery is fully charged. Closed-cell lead acid batteries without the access caps cannot be tested this way.

What is battery manufacturing process?

Figure 1 introduces the current state-of-the-art battery manufacturing process, which includes three major parts: electrode preparation, cell assembly, and battery electrochemistry activation. First, the active material (AM), conductive additive, and binder are mixed to form a uniform slurry with the solvent.

Why is battery manufacturing a key feature in upscaled manufacturing?

Knowing that material selection plays a critical role in achieving the ultimate performance, battery cell manufacturing is also a key feature to maintain and even improve the performance during upscaled manufacturing. Hence, battery manufacturing technology is evolving in parallel to the market demand.

What are the production steps in lithium-ion battery cell manufacturing?

Production steps in lithium-ion battery cell manufacturing summarizing electrode manufacturing, cell assembly and cell finishing (formation) based on prismatic cell format. Electrode manufacturing starts with the reception of the materials in a dry room (environment with controlled humidity, temperature, and pressure).

Who is involved in the battery manufacturing process?

There are various players involved in the battery manufacturing processes, from researchers to product responsibility and quality control. Timely, close collaboration and interaction among these parties is of vital relevance.

How battery manufacturing technology is evolving in parallel to market demand?

Hence, battery manufacturing technology is evolving in parallel to the market demand. Contrary to the advances on material selection, battery manufacturing developments are well-established only at the R&D level . There is still a lack of knowledge in which direction the battery manufacturing industry is evolving.

What are the challenges in industrial battery cell manufacturing?

Challenges in Industrial Battery Cell Manufacturing The basis for reducing scrap and, thus, lowering costs is mastering the process of cell production. The process of electrode production, including mixing, coating and calendering, belongs to the discipline of process engineering.

What is a BMS reset?

The BMS reset helps drivers disable the battery system when replacing the car's battery or after recharging. BMS reset is a way to help the vehicle learn about the new battery's charging cycle. If you replace the vehicle's battery without resetting the BMS, it should automatically relearn its cycle.

How do I Reset my battery management system (BMS)?

Next, locate the BMS reset button or switch on the battery management system. Press and hold this button for 10-15 seconds. If your lithium battery doesn't have a reset button, you can still reset the BMS by discharging it completely and then charging it back up again. This process will help to recalibrate the BMS and restore its functionality.

How do I Reset my lithium battery BMS?

Resetting a Lithium Battery BMS might sound like a daunting task, but it is actually quite simple. The first step is to disconnect the battery from any power source and remove it from its housing. Next, locate the BMS reset button or switch on the battery management system. Press and hold this button for 10-15 seconds.

Why do I need A BMS battery reset?

By resetting the BMS, you can recalibrate its sensors and improve accuracy in monitoring and detecting potential issues with your batteries. Furthermore, excessive heat generation is another sign pointing towards a necessary BMS battery reset. When batteries become overheated during operation, it puts strain on both their performance and lifespan.

What is a BMS battery?

A BMS (Battery Management System) battery is a sophisticated rechargeable battery that uses an intricate electronic system to maximize its performance and longevity. BMS batteries are commonly found in electric vehicles, solar power systems, and other applications that rely on rechargeable batteries. Why Reset Your BMS Battery?

How do I Reset my Ford BMS?

You should see the battery logo disappear from the display screen. If the battery sign isn't flashing and there are no messages about BMS, you have successfully reset the system. You can reset the BMS on your Ford using a computer scanner. If you'd like to reset it using the scanner, take your vehicle to an auto technician who knows how to use it.