Living without a battery backup system will leave you in the dark. Literally. With our country plagued by loadshedding and power outages, more and more South Africans are not only choosing to go the solar route but to incorporate solar batteries into their system as well. There are many benefits to owning a solar battery, like less dependency on the Eskom grid which enables you to save on your electricity bill, give you self-sufficiency, and have a continued electricity source when needed. Solar batteries are also cleaner, quieter, and environmentally friendly. A new trend is to use a battery during peak Eskom hours when tariffs are especially high, enabling consumers to take charge of their power consumption from the grid.
But, solar batteries are a substantial investment, so making sure you get value for money is essential. One of the key aspects to consider is how long your battery will be able to supply your home with power. This information will help you figure out which battery will be best for your needs and ultimately if a battery backup system is the way you want to go. Understanding and comparing the various specifications of an array of solar batteries will make your choice infinitely easier. Working out how long your batteries charge will last while running your home’s electricity needs depends on a few variables. These are your home’s energy needs, and the battery’s capacity.
Working out your home’s energy needs
Having an energy-efficient home will have your battery last for longer, so it’s advisable to lower your energy consumption by using appliances that use fewer kilowatts per hour. You can work out how much power you use per day on average by requesting a utility bill for the last 12 months and dividing it by 365. The average household, according to Eskom, uses over 30 kWh. This amount can be drastically reduced by becoming energy efficient. Those on solar systems report that they use around 6kWh per day. This is a tremendous difference!
It is obvious that with these numbers that the hours your battery will be able to supply your home with power will vary considerably. During a power outage, it is also recommended to only use selected and necessary appliances and devices to enable your battery to supply power for longer. Your inverter output combined with your battery’s capacity should match up to your desired electricity needs.
Capacity is the total amount of electricity that a solar battery can store, measured in kilowatt-hours (kWh). The amount of electricity an appliance or device uses for an hour is measured in kilowatt-hours as well. A 100 Watt light bulb will 1kWh if it is on for 10 hours. If your battery’s capacity is 10kWh, you will be able to keep that light on for 100 hours. By adding more batteries to your system, you will of course add more to your capacity. This is ideal if your power outages are very long or if your energy consumption is high.
Capacity is also influenced by how much charge there is in your battery. If you have a 10kWh battery, you will have almost 10 kWh at your disposal. Most batteries cannot discharge completely because of their chemical compositions, so a minimum charge is always required. When your batteries are connected to a solar system, they can charge every night to have enough capacity to supply you during the whole evening. To do this, you will have to make sure that your solar system’s output is more than you use. Being tied to the grid is still a good idea. When all of your alternatives are not supplying enough power due to foul or rainy weather, it is beneficial to still have access to the grid.
As the cost of batteries decreases with the advancement of technology, more and more consumers will add battery storage systems to their solar systems. Being equipped to make an informed decision will make the experience much smoother with no surprises.
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