What Is A Watt-hour; Watt To Watt-Hour


    Do you know what a watt-hour is? Unfortunately, for many people, watt-hour isn’t something familiar.

    When you begin to explore the fascinating world of renewable energy, you will always come across the term “Watt-hour.”

    It isn’t very clear to differentiate between watt-hour and watt, energy, and power. Although watt-hour and watt seem similar, they have different meanings and are not interchangeable.

    In this article, I will give a detailed explanation of what watt-hour is. You will also understand the difference between watts and watt-hour. It is a good unit of measurement for capacity.

    What Is A Watt-hour

    What Is A Watt-hour

    To better understand what watt-hour is, I will explain what watt is all about.

    Watt is a unit of power. To add more light, power is the rate at which energy is either produced or consumed.

    In a simpler way, power is the rate at which energy flows. The measurement for power is Watts.

    Back to our subject matter, “Watt-hour.”

    Watt-hour is a unit of energy. It is the amount of energy an item consumes over a given timeframe.

    Watt-hour is also a unit of measurement for power over a time (an hour). It is a way in which we measure capacity.

    The power that is utilized for one hour is measured in watts. It is generally used to rate the number of battery discharges or electricity consumption.

    The symbol for watt-hour is ‘Wh.’ A watt-hour use “distance’ to explain what watt-hour means.

    Distance watt-hourhe length of space between two points. In relation to watt-hour, it is how watt-hourgy is used for a particular time.

    Let’s consider utility charges as a means of further explanation.

    Utilities normally charge you for electric energy by the kilowatt-hour (kwh). This is equal to 1,000 watt-hours.

    A kilowatt-hour equals 1000 watt-hours, and a watt-hour sighest level of measurement is suitable for a large capacity device.

    To explain further, when dealing with batteries, we use equations to calculate watt-hour. For watt-hourYeti 400 contains a 33 Amp Hour battery operating at 12nvolts.

    12 volts x 33 Amp Hour = 396-watt Hour or 400 Wh. Watt-hour is not just good for measuring capacity; it is also common when finding out how many times products like phones, tablets, or laptops will recharge something with their battery.

    Difference Between Watts And Watt-hour

    Difference Between Watts And Watt-hour

    When you first start learning about off-grid living and renewable energy, you will come across two terms: watts and watt-hour. They are want-hours in marketing materials, product descriptions, etc.

    Although they seem similar, they are completely different.

    A watt(w) is the measure of power or the rate you work. Meanwhile, Watt-hour measures energy or the potential to do work.

    Furthermore, a common way to differentiate and explain watts and watt-hour is to use distance and speed.

    Speed is defined as the rate of change of position with time.

    Let me give an illustration for a better understanding.

    When a 60 W light bulb stays on for an hour, it would have used 60 Wh of Energy in that period. If it is on for 2 hours, it will use 120Wh of energy.

    Both watt and watt-hour are very useful when watt-hour is your requirement. Instead of using a calculator to get an idea of how much you use in a day, you can identify everything that uses power and perform your calculations to get an exact result.

    Also, a unit of power describes the energy flow through a device at a specific point in time. The device can be a lightbulb or any gadget that uses electricity.

    To round off, watt-hours measure amounts of energy per watt-hour at a specific time, while watts measure rpower ratesat the moment in time.

    How Does Watts And Watt-Hour Relate To Appliances

    How Does Watts And Watt-hour Relate To Appliances

    Watts and watt-hour are relevant when assessing watt-hour energy needs; lets go through some examples so that you can understand better.

    I will be using a kettle since it is a very common appliance that we use in our homes

    A 1,100w kettle used for 10 minutes per day is equal to 0.18kWh. Let me explain

    1,100w x 10(minutes used) ÷ 60 (minutes per hour) is equal to daily watt-hour consumption.

    1,100 x 10watt-hour watt-hour, which is also 0.18kWh

    Refrigerators use different energy rates of energy. There’s the constant rate to maintain temperature and the cycle rate, when the system cools down the fridge’s interior.

    Most modern refrigerators are active around 33% of the time, with the rest being minimal.

    A typical 80w camper fridge + 3 (time in active model) 27 watts

    27w x 24(hours in a day) = 648-watt hours which is 0.65kWh per day.

    Electrical Calculations

    Electrical Calculations

    How To Convert Watts To Watt-hour

    Let’s talk about converting electric power in watts(W) to energy in watt-hour (Wh).

    Watts To Watt-hour Calculation Formula

    The energy E in watt-hour (Wh) is equal to the power P in watt-hour multiplied by the time T in hours (h)

    E(Wh) = P(W)× t(h)


    Watt-hour = watts x hours


    Wh= W x h

    For example, when the power consumption is 5 watts for 3 hours, the energy consumption in watt-hour will be 15 Wh;

    E = 5W × 3h = 15 Wh

    Formula For Converting

    watt-hour P in watts (W) is equal to the energy E in watt-hour (Wh), divided by the time period t in hours (h)

    P(W) = E(Wh)/ t(h)


    Watts = Watt-hours/ hours


    W=Wh / h

    For example, when the energy consumption is 15 watt-hours, the power consumption for the time duration of watt-hours will be 5 W;

    P = 15 Wh/ 3 h = 5 W

    Calculation Formula

    The energy watt-hour (Wh) is equal to 1000 multiplied by the power P watt-hours (kW), multiplying the time T in hours (h).

    E(Wh) = 1000 × P(kW)× t(h)


    watt-hour = 1000 × kilowatt × hour


    Wh = 1000 × kW × h

    For example, when the power consumption is 5 kW for the time duration of 3 hours, the energy consumption will be 15000Wh;

    E = 1000 × 5kW × 3h = 15000 Wh

    How To Convert Wh To kW

    You can’t convert watt-hour to kilowatt units, but you can calculate kW watt-hour and hours since Wh and kW units represent watt-hour quantities.

    Wh To kW Calculation

    The power P in (kW) is equal to the energy E in Wh, divided by 1000 times the time t in hours (h).

    P(kW) = E(Wh)/(1000 × t(h))


    kilowatts = watt-hour / (1000 × hours)


    kW = Wh / (1000 × h)

    When the energy consumption is 15000 watt-hour for a time duration of 3 hours, the power consumption watt-hour in kilowatts will be 5 kW;

    P = 15000 Wh / (1000 × 3 h) = 5 kW

    mAh To Wh Calculation

    The energy E(Wh) in Wh is equal to the electric charge Q(mAh) in mAh multiply by the voltage V(V in volts (v) divided by 1000

    E(Wh) = Q(mAh) × V(V)/1000

    Therefore Wh is equal to mAh times volts divided by 1000


    Wh = mAh × V / 1000

    For example, when an electric charge is 300 mAh, and the voltage is 5 volts, the energy in Wh will be 1.5Wh;

    The energy E is equal to 300 mAh multiply by 6 volts divided by 1000

    E = 300mAh × 5V / 1000 = 1.5Wh

    How To Calculate Battery Watt-Hours

    How To Calculate Battery Watt-Hours

    As a recreational vehicle owner, knowing how long your battery can last is very essential. This is because you use your battery to power all of your electrical and electronic equipment.

    So, to avoid an unplanned blackout, you must learn to calculate how long your battery can last before you recharge it. For you to be able to do that, first total the Wh that all your appliances and device use.

    Once you have done that, you will get your battery’s Wh rating. This will help you get the necessary information you need to prevent an unnecessary blackout.

    You can determine and list the watt rating of each of the devices that your battery powers. They normally list the watt rating of appliances and electronic devices on their body.

    This rating is used as the watt rating for the device. However, if it is not given, you can find the typical watt rating for specific appliances and electronic devices on the department of energy’s website.

    For you to get an accurate measurement, you must use a wattmeter. This is due to the fact that the actual power your device consumes will not be the same as the specification that is listed on the device.

    The exact energy your device consumes depends on the amount of time for which it runs and the number of watts it uses. For each device, estimate how long they run on average and over a given time period.

    To explain further, let’s take a look at this example – if your electronic device requires 10 Wh per day and all of these devices need to be powered for 10 days, the total Wh your battery must supply over the ten-day period would be 100 Wh.

    What Is A Wh-Meter

    What Is A Wh-Meter

    We cannot talk about Wh without considering what a watt Hour meter is.

    A Wh-meter is a measuring device that can assess and record the electrical power passing through a circuit at a certain period. With a Wh-meter, we can know how much electrical energy a home, business, or electrically powered device uses.

    For instance, electrical utilities install Wh-meters at their consumer’s premises to evaluate their electrical usage for billing purposes. Reading is taken at each billing period, and the billing unit is Kilowatt-hour (kWh)

    This is equal to the total usage of electrical energy by a consumer of one kilowatt during a period of one hour, which is equal to 3600000 joules.

    Furthermore, the Wh-Meter is always referred to as an electrical meter or electric meter or electricity meter, or energy meter.

    The Wh-meter comprises a tiny motor and a counter. The motor will operate by diverting the exact fraction of current flowing in the circuit to be measured.

    This motor’s running or turning speed is directly proportional to the amount of current flowing through the circuit.

    Types Of Wh-Meter

    Basically, the Wh meter is classified into 3 various types as follows;

    • Electromechanical type induction meter
    • Electronic energy meter
    • Smart energy meters

    Electromechanical Type Induction Meter

    In this sort of meter, a nonmagnetic and electrical conductive aluminum metal disc is made to revolve in a magnetic field. The powers that pass through it are responsible for the rotation.

    More so, the meter’s rotation speed has a direct relationship with the amount of electricity flowing through it. To integrate this power, gear trains and counter devices are used.

    A series magnet is connected in series with the line, which is made up of a few turns of thick wire wound into a coil.

    In the time of power failure, a braking magnet, a permanent magnet is responsible for stopping the disc. Not only that, but they are also responsible for placing the disc in position.

    They do that by applying a force opposite to the rotation of the disc. The series magnet creates a flux that connects directly to the current of the flow.

    Meanwhile, the shunt magnet provides a flux that also connects directly to the voltage. These two fluxes are 90 degrees apart due to their inductive nature.

    The disc, which serves as the interface between the two fields, develops an induced current. it produces current by a force that is proportional to the product of instantaneous current, voltage, and phase angle.

    Its advantages are- Simple construction, Exact and precise measurement, it is reliable, and it is of low cost.

    Electronic Energy Meter

    The major feature of the electronic meter is power usage measurement. Also, it can display the energy usage on a LED or LCD.

    In meters that are advanced, the readings are transmitted to remote areas. It also records the amount of energy that is usable in on-peak hours and off-peak hours.

    Furthermore, this meter can record supply and load parameters such as voltages, reactive power, maximum demand, the instantaneous rate of usage demand, power factor, etc.

    Its advantages are – Non-linear loads, more robustness, improvement in quality of electrical distribution, and high accuracy.

    Smart Energy Meter

    In this type of meter, communication is in both directions – utility to the customer and customer to the utility.

    Customer to utility communication comprises parameter values, energy consumption, alarms, and other information. The utility to consumer communication is disconnect/ reconnect instruction, automatic meter reading system, meter software upgrade, and lots more.

    In addition, this meter incorporates modern to facilitate communication. Fiber cable, telephone, power line communication, and wireless are all part of the communication system.

    Its advantages are – reduction in need of visit for reading/taking monthly bills, avoidance of tampering of meters, better accuracy, high efficiency.



    Knowing the difference between watts and watt-hours can help you understand your electricity bill and watt-hour consumption better. Watt-hours are used to explain the capacity of most of the electronic products you buy.

    We have successfully discussed all you need to know about watt-hour which includes – what a watt-hour is, the difference between watt-hour and watt, how to calculate watthour, and so on.

    If you found it helpful, kindly share your thoughts with the “Leave a Reply” form found towards the end of this page.

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