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Solar Batteries - How Many Do You Need?

Solar panels on a house

How Many Solar Batteries Will You Need?

Residential solar panel systems are the first step in transforming your home in a more energy-efficient and cost saving living area. Solar panels use energy emitted from the sun and convert it into usable electricity for your house and daily needs. But, solar panel systems can only do so much without a way of storing the energy they collect. To optimize your at-home solar system, consider installing solar batteries. Solar batteries allow you to take all the energy you’ve captured and generated throughout the day, and hold onto it for later use. This can include, at night, on cloudy or rainy days, or during power grid system failures.

Typical homeowner battery needs

When it comes to determining how many batteries your home needs, unfortunately the answer is not always clear. How many batteries your home needs is based on what you want out of your at-home solar panels system, whether that’s resiliency, self-sufficiency, or cost savings. If you consider that one solar battery is 10 kilowatt-hours (kWh) on average, then depending on your goals, you’re looking at:

  • Two or three batteries for cost savings, as that should provide you with enough storage to cover the times where your solar panels aren’t generating electricity, e.g. at night or when there is inclement weather.
  • One solar battery is probably enough if you're looking for resiliency to keep your home going through potential power grid lapses.
  • 8 to 12 solar batteries is around what you’ll need if your goal is self-sufficiency. This is generally for those who want to live a more off-grid lifestyle and is less applicable to your standard family-home solar panel system.

The Effect of Net Metering

In the process of calculating how many solar batteries you may need, consider if you’re in a one-to-one net metering area. When one-to-one net metering is present, you essentially are providing your energy to the power grid in exchange for credits that can help you pull out energy later. This is different from generating energy, storing it on your own, then pulling from it when you need it. The primary purpose of net metering is to ensure that no solar energy is wasted and can all be put to good use, while rewarding the homeowner for contributing what they have generated. In net metering, the power grid is essentially one large battery for you, so the amount of individual batteries you’ll purchase could be less than you think.

Factors that impact battery quantity

Aside from choosing your solar battery amount based on your needs, there are a few other factors that can impact how many batteries you should buy.

How much storage you want

As mentioned earlier, the amount of batteries you’ll need is in part dependent on how much storage you’re looking for. Depending on how heavily you want to rely on your personally generated electricity, you could need anywhere from one battery to twelve batteries. The typical homeowner generally uses their solar panel system for cost savings and a reduction in their carbon footprint. This means, one battery on the low end and three or four batteries on the high end. This is enough to store electricity for times when your panels aren’t generating and also to be prepared during periods of power grid failure.

Size of your home

The size of your home impacts the amount of batteries you’ll need for two primary reasons, one the larger the home the more electricity is generally needed and the larger your home the more solar panels you can install. Larger homes tend to have larger roofs which means that you can install a larger array of solar panels. The more solar panels you have, the most electricity you can generate, meaning more batteries will be needed to store said generated current.

Energy usage of your home

A key difference from homeowner to homeowner is the amount of electricity used in the house. Some families rarely turn on lights and have only a few major appliances, while other families may have a large number of electric appliances and thus, use a lot more electricity. To calculate the current power consumption for the average American household, look back at the last year in bills and add them together for a year's worth of energy consumption. Then divide this number by 12, to find, on average, how much electricity your home uses per month. This will give you a fairly accurate idea of how many solar batteries your home may need.

Largest energy usage factors

When thinking about how many solar batteries you may need, consider how many heavy electricity “loads” your home may have. A “load” can be defined as anything that uses electricity. The difference between a heavy load and a light load, is just how much they use. Common heavy “loads” include things that remain plugged in all day, every day, like refrigerators. And, things that may not be used year round, but when they are it’s a heavy expenditure, like air conditioners. If your home has multiple fridges or you live somewhere warm and use your A/C system often, you may need to opt for a higher number of batteries.

Flat vs. variable electricity rate

Lastly, consider your electricity rate plan when determining the amount of batteries to purchase. Depending on where you live, in a variable electricity rate area, you can sell your stored electricity to the grid at a premium price. This is called “arbitrage”. If you live in an area where this is the case, perhaps investing in more batteries to store more energy could help you generate more income for that store of energy. However, keep in mind that you can’t hack the system by installing a large amount of batteries, storing a ton of energy, and then selling it back to the grid for a high price. In most places, there is a cap or maximum amount of electricity that you can arbitrage.

Call The Experts Today

Finding the right amount of solar batteries home is a personalized experience, so don’t go for a one-size-fits all approach. Trust the experts at SolarUnion to help you design the perfect solar panel and storage system for your home and its needs.

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