Home solar battery system set ups
Types of home solar batteries
Lithium-ion batteries
Lithium-ion batteries are currently the most common type of battery technology used in home solar battery installations. They are compact, light and have high energy densities. They can be charged efficiently and have lifespans of up to 15 years.
Lithium-ion batteries have become more accessible to households as the cost continues to decrease.
Other types of batteries
There are 2 other main battery types used in solar battery installations in Australia. Battery technology is always progressing, and more options may emerge in the coming years.
Lead acid batteries
Standalone (also known as off-grid) solar systems have historically used lead-acid batteries. These are the same batteries used in petrol cars.
Lead-acid batteries are reliable and have low upfront costs. However, they are less suited for solar storage as they must be fully charged regularly, are slow to charge, heavy, and have a short lifespan.
Flow batteries
Flow batteries store energy in a liquid form (electrolyte), rather than a solid form like in conventional batteries. The liquid form makes flow batteries scalable, meaning it’s easier to increase their capacity by adding more fluid to the tank.
The fluid is usually non-flammable, which helps increase the battery’s safety.
System add-ons
Dynamic connections
Dynamic connections are new to Queensland customers and offer a more tech savvy (or dynamic) approach to selling electricity back to the grid. Older ‘fixed connections’ have set limits on how much electricity can be exported back to the grid. Fixed connection limits are pre-programmed into your inverter.
Limits on dynamic connections are sent to your inverter via the internet, depending on network conditions. This live exchange of information can help determine the best time to charge your battery from the grid.
There may be a fee for a dynamic connection.
Home energy management system
A home energy management system (HEMS) helps you control energy use in your home without compromising your lifestyle.
A HEMS is a technology platform that monitors your energy consumption and controls at least 1 asset, such as a solar battery. Most HEMS can connect multiple appliances such as hot water systems and lighting. A HEMS allows you to switch connected appliances off remotely or set scheduled running times, helping you save money on electricity bills.
At the centre of the HEMS is a ‘hub’ that connects to your household’s electrical switchboard. Using your phone or computer, you can access data from the hub to monitor and manage your appliances and energy consumption.
A HEMS can estimate your energy demand and optimise the use of your solar battery. Many HEMS can factor in current and next day weather conditions, energy costs and the grid’s ability to delivery electricity.
Once a HEMS is installed, you can choose to manage your electricity yourself or allow a service provider to do it for you.
If you choose to have your service provider manage your system, you should receive some compensation in return for control of your devices. Compensation may include upfront hardware discounts, reduced retail rates, or fixed and variable rewards.
Virtual power plant
Virtual power plants (VPP) are an important step in the renewable energy transition and offer households another way to reduce energy costs via their solar battery systems. A VPP can give you access to more affordable energy deals or pay you for your excess energy.
A VPP is a collection of small devices, such as multiple household solar battery systems, working together to operate like a power station. Electricity retailers run the VPPs and coordinate the devices to provide power during peak periods or store grid energy when there is excess supply. The devices making up a VPP can be close together in the same neighbourhood or spread across the network.
Participating in a VPP program can bring the following benefits:
- payment for allowing the VPP network to use your stored electrical energy
- more efficient use of solar electricity to support the grid and other consumers
- reduced impact of surges on the grid and decreased network costs for consumers
- greater solar PV and battery uptake in your community.
VPPs can have drawbacks, which is important to consider before signing up to a VPP program.
Potential drawbacks include:
- reduced control over your own energy usage
- over-discharge of batteries, reducing the lifespan of your battery
- lack of reserve capacity for your household in case of a power outage
- loss of the ability to shop around for cheaper retailers due to lock-in contracts.
VPP is an emerging technology and may not yet be available in your area.
Many VPP programs have specific product requirements, it’s important to review these requirements to ensure the system you install can participate in your VPP of choice.
Your system set up
Understanding what home solar system you currently have and what you might like in the future is a key step in planning your installation. Below are 3 home battery scenarios.
To keep your household safe, be sure to use an accredited home solar battery installer.
New solar and new battery
Installing a new solar energy system and new battery at the same time has financial and practical advantages.
A combined system with a new battery and a new solar system will normally have shorter payback (recouping the costs).
Adding a battery to existing solar
Adding a new battery to an existing solar system, also called retrofitting, may have a longer payback period than installing a new solar and battery system.
It is important to determine whether your existing solar system is ‘battery ready’. Usually, you will need to install a dedicated battery inverter with your new battery. Most battery products on the Australian market can now be sold as a package deal with a compatible inverter.
Some providers might offer to replace the existing solar inverter with a single hybrid inverter that connects to both the solar and battery. This is not possible in all cases and can have a major impact on your overall system compliance.
Providers may also offer to connect the battery to your existing solar inverter by fitting a dedicated DC to DC converter between the solar panels and the battery. This option will mean the battery can only be charged from solar, and not from the grid.
Getting a new solar system and installing a battery later
If you are thinking of installing a solar system now and a battery in the future, be cautious. Any hybrid inverter installed now could become obsolete by the time you look to install a battery. This is because the technology is advancing fast, and inverters may become outdated for newer battery technologies.
If you’re interested in purchasing a battery-ready solar system now with the intention of adding a battery in the next few years, the main questions to ask the battery retailer are:
- When I add a battery in the future, will it be compatible with the existing inverter?
- Is there any additional equipment (besides the cabling and the battery) that will need to be purchased and installed when I get a home battery?