How do Solar Battery Backups Work?

Are Solar Batteries Right for my Home?

You’re considering getting a solar PV system installed for your home and you’ve been doing a lot of research online. Although there are a lot of options, many installers, various brands of solar panels, at least the basics of a solar power system are starting to make sense until you run across the battery backup option. 

Solar batteries provide electrical reliability, they safeguard your home against blackouts and power outages, and can optimize your solar PV system’s performance; they also add quite a hefty price to your system. So your questions: How do they work, are solar batteries worth the additional costs, and are they needed for your home’s solar PV system?

The answer to these questions are “it depends”. 

But before we dive into that, let’s quickly review how a solar PV system works. 

How a Solar PV System Works

Your usual solar PV system is composed of: 

  1. Solar panels
  2. Inverters
  3. Racks or mounting that mount the solar panels onto your roof
  4. A system to monitor your solar PV system’s performance

The solar panels work with the sun to produce electricity, the inverters turn the electricity produced by the solar panels into electricity your home can use, the electricity is then passed through your panel and into your home when you need it. Most solar PV systems today also come with a way to monitor your solar PV system’s performance, how much electricity it produces, and so on. Also read The Parts of a Solar PV System. 

A common misconception about solar is that you will be completely independent from the electricity grid. While solar definitely provides independence, most homes that have solar are still connected to the local grid. When panels are producing an excess of electricity, or producing electricity while you’re not using it, the electricity is fed into the grid. Reversely, when you are using more power than your solar PV system is producing, you draw power from the grid. 

But don’t worry, all this is tracked and monitored by your meter and the utility. Every time your solar PV system produces more electricity than you use, you receive credits from your utility. Reversely, when you use more electricity than is produced by your solar power system, you draw electricity from the grid. Instead of paying for the electricity, you use the credits you have to pay for the electricity you draw from the grid. This is what is called Net Metering. 

A well designed solar PV system will take this into account and in most cases, you will wind up with credits left over at the end of each twelve-month period. 

What Do Solar Batteries Do?

What do solar batteries do?

Solar batteries do two things, primarily: 

  1. They store power for your home to use at night when your solar PV system is not producing energy and
  2. They store solar power for your home so that you don’t experience any blackouts or power outages if the grid fails to perform or has a temporary outage.

In the above picture, if you scroll the centerline from left to right you will see how your batteries work with your solar PV system during the day and during the night to provide your home with solar power. 

Solar batteries not only provide electrical reliability, but they work with your solar PV system to optimize its performance and in some cases can help reduce the number of solar panels you need for your home. 

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