Whether connecting your solar panels to the grid or adding batteries, there are many specifications to consider when buying these products. On the product information sheet, you will find amps, volts, watts, and other different units of measurement. It's important to understand what these numbers mean and their differences, so in this blog, we'll explain the definitions of amps, volts, and watts to help you make the right choice.
What are amps, watts, and volts?
Among the basic concepts of electricity, the units amp, watt, and volt are very important. Once you understand their concepts, you will see that they are interrelated and can be calculated using a simple formula.
What is an amp in electricity?
Always preceded by the letter 'A', amp is short for ampere, a way of measuring the amount of electricity flowing through an electrical circuit. The word is named after the French physicist and mathematician André-Marie Ampere, who laid the foundations of electrodynamics.
First of all, you need to know what electricity is. Current is the 'flow' of charged particles (such as electrons and ions) through a conductor. The number of amperes is the number of electrons flowing through a circuit. The higher the amperage, the more current flows through the circuit.
The best analogy for amperage is the flow of water through a pipe. To get the right size of pipes and other components of a water system, you need to measure the flow. With electricity, you need to measure the amperage to get the best combination for the circuit.
Typically, socket circuits and general lighting are rated at 15A. However, in newer buildings, you'll find 20A circuits for laundry rooms, bathrooms, kitchens, and even appliances such as fridges or dishwashers. Larger appliances such as tumble dryers are usually rated at 30A.
What is a watt?
Watts describes the rate of energy conversion per unit of time. More power means that the device can convert energy more quickly. In other words, wattage is the amount of power an electrical appliance consumes.
In our daily lives, we often see watts used to describe the power of an appliance, such as the wattage of a light bulb to indicate the amount of electricity it uses or the power of an air conditioner or furnace.
What is a volt?
In simple terms, a volt (short for voltage) is the pressure that forces electricity through a wire. It is also sometimes described as the speed at which individual electrons move through a circuit. In the United States, electricity from the grid is typically delivered at two different voltages: 120 volts and 240 volts.
Generally, small household appliances such as televisions, light bulbs, mobile phone chargers, and computers only require 120 volts. On the other hand, large, power-hungry appliances such as furnaces, clothes dryers, space heaters, and air conditioners require 240 volts.
How to calculate amps, watts, and volts?
1️⃣You can use Ohm's law to calculate the amperage from watts and volts.
Amps = Watts / Volts
If you know the wattage and volts of an appliance, you can easily calculate its amperage. For example, if the wattage and volts of the appliance are 2400W and 1200V respectively, the amperage is:
Amps = 2400W/120V = 20A
2️⃣The same Ohm's law can be used to calculate watts from volts and amperes.
For example, if the appliance uses 10 amps and 120 volts, the wattage would be:
Watts = 10 amps × 120 volts = 1200W.
The higher the wattage, the greater the output and power of the appliance.
3️⃣Voltage calculation
Volts = Watts / Amps
If the appliance consumes 1000 watts and 20 amps, the voltage can be calculated as follows:
Volts = 1000W / 20A = 50V
What is an ampere-hour?
Ampere-hour (Ah) is a unit of charge capacity and is used to measure the storage capacity of a battery. It is one of the most important factors to consider when buying a battery. This number tells you how long you can use your battery before it needs to be recharged.
A higher amp-hour rating means the battery has more capacity and can hold more charge, giving you more time to use it. Lithium-ion batteries are the latest type of battery. They have the highest amp-hour rating in their class.
Common misconceptions about amps, watts, and volts
Many people have misconceptions about electrical systems
Does higher voltage mean more power?
The amount of power depends on the relationship between voltage, current, and the load in the circuit. Although the higher the voltage, the higher the power, it is important to remember that power is the product of current and voltage. The voltage will only be higher if both the voltage and the current are high.
Is a higher current charger better?
Charging a battery requires a constant current to restore energy safely and efficiently. The current of the charger is always higher than the capacity of the battery. If the charger's current is lower than the battery's, the charger will overload. The charger will struggle to deliver enough power and will overheat. If this happens frequently, it will have a short life and may even catch fire.
On the other hand, too much charger current can cause the battery to overheat and overcharge, damaging it. The best advice is to check the charger specifications in the manual to avoid problems.
Smart batteries, such as lithium-ion batteries, have a management system to address these issues: the BMS allows communication between the battery and the charger to provide the optimum current configuration.
Therefore, a higher charge current is not better. It is important to follow the battery and charger specifications and use the appropriate charger.
The higher the current, the larger the wire size required?
A circuit is made up of components connected by wires. To work properly, the current must be stable. The wider the wire, the better the transfer of electrons. The amperage therefore depends on the size and type of wire. One of the most important aspects of wire size is the issue of overheating. If wires are overloaded, they can overheat and cause short circuits and fires.
What is the difference between volt, ampere, and watt?
Amps, watts, and volts are used to measure electricity and indicate the efficiency and power of an electrical system. Volts are used for potential difference and watts indicate the energy consumed. Amps are used to measure the flow of current.
Volt
The volt is the simple basic unit of voltage, representing the difference in potential between any two points. It also refers to the voltage across a circuit. As the volt increases, so does the current.
Current flows rapidly through a circuit system only if the circuit is unbroken. Voltage is the difference in potential between two points on a wire or circuit. The table below lists the different appliances and their voltage levels.
| Object or equipment | Voltage (V) |
| USB | 5 |
| Car battery | 12 |
| Electric vehicle batteries | 300-400 |
| Household batteries | 1.5-9 |
| Power lines (high voltage ) | 10000-20000 |
| Lightning | 100 million |
Watts
The watt is often referred to as the basic unit of electricity in any electrical system. It determines how much energy the system delivers per second. The higher the wattage, the more power and energy is produced.
Understanding the wattage will help you choose appliances that use less energy. It will also help you determine how many watts of electricity your solar system can provide for your home. The table below shows appliances and their average wattage consumption.
| Object or equipment | Cost per hour | Voltage (V) |
| Heat pump | $2 | 15,000W |
| Clothes drier | 0.55 Cents | 4,000W |
| Heater | 0.20 Cents | 1,500W |
| Water pump | 0.40 Cents | 3,000W |
| Hair dryer | 0.16 Cents | 1.200W |
| Fridge | 0.14 Cents | 1,000W |
| Light bulb | 0.008 Cents | 60W |
Amps
If you're wondering what current is measured in, the answer is amperes. The ampere is the basic unit of electricity and is used to measure how many electrons are present. It also determines how much electricity or power is being delivered through a wire.
Amps, Volts, Watts, How to design an electrical system?
To design an electrical system, you need to identify needs and expectations. You need to choose components that meet each other's specifications. For example, you do not want to use a low-capacity battery to power an electric motor. To design a circuit, you need to have a good understanding of voltage, current, and wattage.
