Solar panels can help reduce electricity bills, particularly on sunny days. However, most homes still need electricity after sunset, when rooftop panels produce little or no power. Home batteries offer a solution by storing extra solar energy generated during the day for use at night.
So what can a family do with the solar energy which is produced during the day? One answer is to use a home battery. This enables the battery to store the extra electricity while the sun is shining and then allows the household to make use of that energy later on, even at night.
What counts as a home battery?
Consider the battery in your mobile phone: you charge it as the power level falls and then use the energy it stores during the day. A home battery works on the same principle, except that it is set up to provide electricity to the household appliances.
If the electricity produced by the solar panels exceeds that which is needed by the house, the surplus can be used to charge the battery; and when evening comes, the electricity which has been stored can then be used to operate appliances without having to rely completely on the grid.
The lithium-ion technology is used by the majority of modern home batteries systems since these batteries are able to store a useful amount of energy, occupy only a small amount of space and can be recharged many times.
How do solar panels and a battery work together?
A typical home solar system together with battery storage consists of solar panels, an inverter, a battery and a control system, which all function as a unit to handle the electricity that is generated and consumed by the household.
Solar Panels Make Electricity During the Day
Solar panels produce electricity when they are in the sunlight, and on a bright afternoon the system can generate more power than the family requires at that moment. For instance, even though the panels are producing a lot of power, electricity usage may still be low since everyone is at work or school.
The Inverter Helps Manage the Power
Solar panels generate direct current (DC) electricity, whereas most household appliances operate on alternating current (AC), and an inverter is used to change the electricity into the form required by these appliances. In a solar-plus-battery system, an appropriate inverter also serves to send the electricity to the battery when charging is required.
Extra Solar Power Goes Into the Battery
After the home’s immediate demand for electricity has been satisfied, the system can direct the excess solar power to the battery. Rather than using up all the electricity as soon as it is produced, the household can save some of it for later use. The quantity stored will depend on the amount of extra power that the panels generate and on the amount of space available in the battery.
The Stored Power Is Used After Sunset
Once the sun has set, the solar panels cease to generate significant quantities of electricity and the battery is then able to provide the stored energy to the house. When the battery is empty, a house connected to the grid can take electricity from it. The way in which power is distributed between the battery and the grid is determined by the system’s settings.
A Simple Example: Solar Power After Sunset
Picture a family who have roof-top solar panels which produce electricity all day long. In the afternoon the panels supply power to the refrigerator, the washing machine and the other appliances. They also generate more electricity than the family requires.
The additional energy is used to charge the home battery.
That same evening the family turn on the lights, switch on the fans and watch television. Although the solar panels are no longer producing enough power the battery is still able to supply some of the electricity required.
The family are now using the solar energy which they had collected earlier in the day, and this is one of the principal reasons why people decide to install batteries on their rooftop solar systems.
Certainly, the battery won’t stay charged forever. If you switch on a number of appliances at the same time, more energy is used and the power available may therefore be exhausted earlier.
How much electricity can a home battery hold?
There are various sizes of home batteries, and their capacity for storage is given in kilowatt-hours (kWh). Let us take a battery which has a capacity of 5 kWh. In theory, it should be able to power a load of 1 kilowatt for five hours. The actual time it will last might be less since some energy is lost during the conversion process and not all of the battery’s rated capacity may be available for use.
A household which mainly needs only lights, fans and phone charging will need less storage than one that wants to run an air conditioner at night. Which of your appliances would you like to use and for how long is therefore the first question to ask when selecting a battery; this answer will then show you what storage capacity you need.
Can a home battery provide assistance during power cuts?
It can, but there is a important point to verify before purchasing one. It is not the case that all solar systems continue to supply electricity when the grid fails; some of them shut down automatically during a power outage for safety reasons. In order to offer backup power, the system must have suitable battery equipment and the correct backup function.
If the right arrangement is used, a battery can cause important appliances such as lights, fans, a refrigerator or a Wi-Fi router to continue working during a power failure. The number of appliances it can support will depend on the capacity and power output of the battery; homeowners should ask their installer which circuits will stay powered and for how long the battery is expected to last.
What are the primary advantages of a home battery?
A major benefit is that you can use some of the solar electricity which has been produced during the day even after sunset, thus decreasing the amount of power that a household has to purchase from the grid.
Home batteries can also provide electricity during power outages, provided the system is designed to offer backup power. Many home battery systems come with monitoring apps that show how much electricity the solar panels generate, how much energy the battery stores and how much power the household uses.
The amount saved is not the same in all houses since it varies according to the electricity tariffs, the solar power produced, the household’s level of consumption and the local regulations concerning the supply of any surplus power to the grid.
Should it be worth one’s while to install a home battery?
A home battery may be useful, but it increases the cost of a solar system. Whether or not it is worth the investment will depend on how the household uses electricity and what it wants from the system.
For a family that uses a lot of electricity in the evening, home batteries can store solar power generated during the day and make it available when needed. In areas where power cuts are common, home batteries can also provide backup electricity, making them a useful option for households looking to get more value from their solar energy system.
Before coming to a decision, it is important to compare the installation cost, the usable storage capacity, the warranty and the safety features and also to consider whether a smaller battery would be sufficient to meet your needs rather than paying for storage that you will rarely use.
Conclusion
Solar panels produce electricity whenever there is sunlight, but a home battery makes that energy useful after dark by storing the excess power during the day and then supplying it when the household needs it.
If you are a homeowner thinking of fitting solar panels onto your roof, home batteries are worth considering, especially if you want to use solar energy in the evening or have backup power during outages. The right choice will depend on your daily electricity needs, available space and budget. Understanding how home batteries work can make the decision much easier.
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