So, you’re wondering “how much solar battery storage do I need?”

Good question – this is one of the most common questions that we receive at Captain Green Solar. The solar battery size that you choose for your solar panel system will determine how much solar energy can be collected and stored.

There is substantial interest in the development of solar battery storage solutions. As battery technology develops, and the demand for renewable energy solutions such as solar increases, the accessibility to solar batteries is only rising. As such, whether you’re already operating with a solar panel system or you’re considering investing in solar, it is essential to be well-aware of your battery storage options.

At Captain Green, we are proud to be one of Australia’s top solar companies. Having operated for over ten years, we provide expert advice and installation of solar panel systems and solar battery storage solutions. We’re here to break down the solar battery sizes in Australia so that you can make an informed decision on what size solar batter you need.


What Is A Solar Battery?

what are solar batteries infographic

A solar battery refers to a piece of technology that stores energy collected from a solar PV system. The solar panels absorb energy from the sun, where the energy is converted to electricity to power the property. Any excess energy is stored in a solar battery, where a property can collect and store the energy for later use rather than sending it back to the grid. Essentially, your solar battery is a storage system for excess energy collected by your solar panel system.


How Much Solar Battery Storage Do I Need? The Basics

The first thing to do when asking yourself “How Much Solar Battery Storage Do I Need?” is to identify your reason for purchasing battery storage in the first place. For some, it is about saving some excess energy being fed back into the grid others want protection from blackouts, and for some climate warriors, the reasoning comes down to trying to create a carbon-neutral home.

Another critical consideration of how much solar storage you may need is budget. A complete solar storage system can be expensive (albeit, cheaper than ten years ago), and the amount of storage you need depends on:

  1. How much energy you produce: The size of your solar array and its efficiency will impact how much power it is supplying to your home
  2. Your daily energy usage requirements: Daily energy usage varies between households depending on the number of occupants, geographic location, type of building and general household energy usage (think air-conditioners, pools and appliances). Some people find their solar system partly covers their energy usage, and others find they are supplying excess energy back into the grid.


The simplest way to get an idea of your energy usage is to look at your energy bill. You can work out your daily usage by dividing your monthly bill by 30 or annual bill by 365 – this will provide an exact amount of energy you’re using each day, on average.

Another great way to calculate your energy profile is by fitting an energy monitor on your home. If you already have solar panels set up, you will likely have access to your energy’s output and usage. If not, several solutions can be explored to gain a better understanding of your energy profile.

Finding the notion of calculating your energy profile for solar batteries confusing? Our experienced team would also be happy to provide expert advice so you can get set up with a system catered to your needs.


solar battery size tips

For many, their solar panels are connected to the mains electrical grid, where the property can send back any excess energy collected, and benefit from the feed-in tariff. This option means the property is also connected to the electrical grid as a backup for electricity.

However, suppose you find you often have excess energy from your solar system and wish to take advantage of it without sending it back to the grid. In that case, a solar battery storage system is an excellent solution for you. Solar battery storage is ideal for properties in which mains electricity is not a viable backup option. Solar battery storage allows for properties in Australia to become self-sufficient and entirely off-grid.


How Many Batteries Do You Need for A Solar Power System?

When considering how many batteries you need for a solar panel system, try not to think about it like stacking up a wall of triple-A batteries!

Batteries for solar storage are generally designed to hold power as a complete system. There are differences in size; smaller systems may be 2kWhwhile a larger system could hold up to 10 kWh of stored energy.

Battery sizes are expressed in kilowatt-hours (kWh). It is easy for the average consumer to be confused by the difference between kilowatts, a measurement of power, and kilowatt-hours, a measurement of energy.

The energy capacity of a battery is measured in kilowatt-hours. For example, if a battery stores 15 kWh of energy and its power is 5 kilowatts, it can be charged or depleted at a maximum rate of 5 kilowatts and would take 3 hours to be fully charged.

To put this into the case of one of our solar batteries, the Tesla Powerwall, it has a 13.5kWh of usable energy with a charge and discharge rate of 5kW. So, if you had a 5kw solar system, you would be able to charge it fully in 2.7 hours.

Most people are out at work during the day, using about 1/3 of energy during the day. However, when it is dark, and everyone is at home, solar panels aren’t producing any energy – you’ll need to rely on another source. This is where a solar battery will come in really handy.


solar battery size for 5kw


Case Study – Battery Size for 5kw Solar System

In the case of Battery Size for 5kw Solar Systems, it all comes down to where you’re located in Australia, the positioning of your solar panels and how much energy you both produce and need to produce for back up.

If you already have a 5kW system or are considering purchasing one, you’ll need to consider the correct battery size for a 5kW system. Look at a 5kw solar panel system specifically, you will likely need a battery with a capacity of at least 10kWh, more likely, up to 13.5kWh.

Generally speaking, a 5Kw solar panel system will produce anywhere between 1721 kWh per day, depending on where you’re located in Australia. For most properties, approximately two-thirds of a system’s energy production is fed back into the grid which is around 13 KW a day. Instead of being fed back into the grid, this 13kW could be collected and stored solar power in your battery.

However, if your property uses closes to half of your power during daylight hours, this means that half of the energy produced will be sent back to the grid. Consequently, you could use a smaller size solar battery like a 10kWh.

The exact battery size needed will come down to how much electricity you typically consume during daylight hours and what you wish to achieve with a solar battery. In our experience, the Tesla Powerwall battery provides an exceptional solution for a 5kw solar panel system.


Talk to the Solar Battery Experts Today

Hopefully, this article has left you with a better understanding of solar battery storage and how much storage you would need. The bulk of this information is theoretically sound; however, to get the most out of your own setup, it is important to have a thorough understanding of both your energy usage and solar energy profiles.

At Captain Green, we can provide expert calculations to size about storage solution that is right for you. Our technicians have years of industry experience in helping our value customers achieve their solar goals. We’re always here to chat and are happy to answer all questions related to solar panel installation, solar panel packages, inverters, solar batteries and commercial solar. If you’d like to talk to a solar panel professional, call us at Captain Green today on 1300 361 682