The conversion from watts to watt-hours is very important for solar panel systems to help you determine your household’s electricity consumption from the rated power of your solar panel system, which in turn will help you determine the range of appliances that your solar panel system will power and the size of the solar array and inverter that will need to be installed to support it.
Below, this article will introduce you to what is a watt, what is a watt-hour, and the conversion method between the two.
1. What is a watt (W)?
A watt is a unit of power, symbolized as W. It is one of the most widely used units of electrical physics, and is usually used to describe how much energy an appliance consumes to do a certain job. The more energy it takes to do the job, the greater the wattage, and conversely, the less energy it takes to do the job, the smaller the wattage.
Watt can also be used to describe the power generated by a power generating device, for example, the watt value of a solar panel system refers to the rated power generated by the solar panel under ideal conditions.
2. What is a watt-hour (Wh)?
A watt-hour is a unit of energy, symbolized as Wh. It is also a common unit used within electrical systems such as solar panels. When used to express the energy consumed by a household appliance, 1 Wh is defined as the amount of energy required to run a 1 W appliance for 1 h. In addition to this, it can be used to express the energy consumed by a battery pack.
In addition to this, it can also indicate the capacity of a battery pack and is a battery property that we need to focus on when selecting a battery pack for a solar system.
3. How to realize the conversion from Watts (W) to Watt-hours (Wh)?
After learning about the units of measurement for both watts and watt-hours, we can start to learn the conversion formula between the two.
First of all, we need to know that although both watt-hours and watts are common units of measurement within electrical systems, they are not essentially the same kind of unit, as one is a unit of energy and the other is a unit of power. Therefore, in order to realize the conversion relationship between the two, we need to introduce an intermediate physical quantity: operating time (T), then the specific conversion formula is as follows:
P (W) = E (Wh) ÷ T (h)
The E in the above formula refers to the energy consumed when the appliance is in operation, P refers to the power value of the appliance, T refers to the working time of the appliance. The conversion of units from watt-hours to watts can be achieved according to the above formula:
Watt = watt-hour ÷ hour
In order to better understand and master the above formula, the following will be an example of a 200W air conditioner, assuming that the air conditioner is kept on for 5h per day, you can calculate the daily power consumption of the air conditioner according to the above formula: 200W x 5h = 1000Wh.
This formula not only helps you to determine whether the power consumption of the appliance is within the power supply capacity of your solar panel system, but also helps you to choose whether to buy the appliance with this power consumption level according to your budget for electricity.
4. What devices within a solar panel system can the conversion from watts to watt-hours be applied to?
There are a number of solar system devices that involve the conversion of physical quantities from energy to power, the most important of which are the solar inverter and the solar cell bank.
Solar Inverters
A solar inverter is an important electrical device that connects the solar panels to the power lines of your home’s appliances. Its main purpose is to convert the direct current from your solar panels into alternating current and supply it to your appliances.
But the fact is that all the electricity produced by your solar panel system is first stored in the inverter’s batteries. In order to ensure that the inverter batteries will not remain at a low level all year round and suffer damage such as shortened battery life, you need to choose the right inverter battery capacity according to the size of your solar panel system.
In order to choose the right inverter battery, you need to know the amount of electricity your household consumes (in watt-hours) and the generating capacity of your solar panel system (in watts). Calculating based on the above data by substituting it into a conversion formula can help you choose the right solar inverter batteries that are not far beyond your household’s storage requirements.
Solar Battery Packs
The main purpose of a solar array is to store the excess power produced by the solar panels during the day, so that at night and in bad weather, instead of purchasing power from the grid, the solar power can be used to keep appliances running.
Based on this type of energy supply, it is worthwhile for most homes to install a solar array, which can go a long way in increasing the percentage of your home that is powered by a solar panel system, saving you a significant amount of money on your electricity bill. However, solar arrays are more expensive, and solar arrays with too high a capacity will be much less utilized if they are matched with a solar panel system that is rated to generate less power. Therefore, it is important to choose a solar cell that suits your needs.
In order to choose the right size solar panel, first we need to know how much power your solar system will generate (simply multiply the power rating by the peak sunlight hours) as a way to make sure your solar panel is not too large. Secondly, you need to know the amount of electricity your home uses (in watt-hours) and convert it to the rated power of your solar panel system using the conversion formula above to ensure that your solar panel is not too small.
