Solar power continues to gain popularity as an alternative to grid-based electricity. Because of that steady increase in usage in households across the country, there is a uptick in the number of products available to bring the power of the sun to bear for your home electricity needs. While many focus on the solar panels when designing their array, of equal importance is the battery backup that will store excess power to get you through sunless days and support your power needs regardless of the weather.
But selecting a solar battery system isn’t as simple as picking out a lead-acid or lithium battery and incorporating it into your system. In order to meet the energy needs of your home seamlessly with no breaks in service, you need to ensure that you have adequate battery capacity to cover your usage for several days, even if the sun refuses to shine. Keep reading to learn how you can properly determine how much battery capacity you will need to support your solar power system.
Step 1: Figure Daily Energy Use
First, you’ll need to do a calculation to find the daily energy use figure for your home. For each appliance that will depend on solar power, get the wattage rating. Then, determine how many hours each day that appliance will be used. Multiply that times the appliance wattage. Add the figures for each appliance together to get your total daily energy use number for your household. The number will represent watt-hours.
Step 2: Autonomous Days
Imagine the sun doesn’t shine at all for several days. How many days would you like to have sustained power at current usage levels if there is no sun to recharge your system? Automonous days refers to days that you can continue at normal daily energy use rates without running out of power. Most homeowners choose to construct battery banks with capacity to store two to five autonomous days worth of power.
Step 3: Battery Bank Capacity
Once you have these figures completed, you can calculate the minimum capacity you’ll need to support your normal household power usage using only solar power. Take the watt-hours per day figure you generated and multiply it by the number of autonomous days you desire. Since your batteries should never be discharged past 50 percent capacity, you then must multiply the resulting number by 2. That number will be rendered in kilowatt-hours, but you want to convert it to amp hours. That can be done by dividing the total number in kilowatt-hours by the battery or system voltage.
Finding the right solar battery capacity is easy if you follow these steps. It’s important that your system can not just generate power efficiently, but that you also have the capacity to store the energy to get you through those sunless days without alterning your usage patterns.