What is battery storage and how does it work for me?

Reduce your reliance on the electricity grid and store your solar energy for use when the sun’s not shining.

There’s no doubt that battery storage is the way of the future – and right now there are government rebates and technically excellent battery systems available that make energy storage an attractive investment for many.

No matter whether you want an off-grid or on-grid storage system, Specialized Solar has the expertise to design, supply, install and maintain a high quality, reliable battery storage system that’s going to achieve your energy storage requirements.

Advantages of battery storage

  • Protection from power outages
  • Increased independence from the electricity grid
  • Reduced electricity costs
  • Greater protection from ongoing electricity price rises
  • Reduced carbon footprint
  • Greater control over your electricity usage

How does a battery system work?

A battery system allows you to store excess solar power generated by your solar panels in a battery instead of exporting it to the grid. You can use this energy in your home when the sun’s not shining – typically at night or on cloudy days – instead of buying power from your electricity retailer. The right battery can provide power to your home for hours, even days, when combined with solar – and even in a power outage.

On-grid or off-grid?

For properties currently on mains electricity, we generally recommend an on-grid battery storage system instead of going completely off-the-grid (as appealing as that can be for many people).

Off-grid systems typically cost tens of thousands of dollars with an average price of $25,000-$40,000 for a family home. Typically, people will consider this investment if they live on a rural property that doesn’t have a mains electricity power connection.

On-grid battery systems, whilst still quite pricey, are less expensive than off-grid systems. With the Victorian Government battery rebates, the cost can be around $10,000-$15,000.

Battery Ready Solar Systems

You’ll be glad to know that every single solar system we install is ‘battery ready’ which means you can easily add battery storage now – or wait until later.

Is on-grid battery storage worth it financially?

This is the million dollar question for most people! The answer is ‘it depends’.

If you are looking to get a quick payback on your battery investment the answer is probably ‘no, wait until prices drop.’ That’s because, for most households and businesses, the payback period is longer than the 10-year battery warranty.

If, however, you are concerned about the possible economic loss resulting from power outages – or you absolutely have to have 100% power in your home or business – investing in battery storage could be worthwhile.

Another common situation prompting people to get a battery is when their network distributor refuses to let them export any of their excess solar power to the grid (this is unfortunately increasingly common for new solar installations). Instead of just accepting this state-of-play, some people respond by getting a battery installed so that they can store their excess solar power and use it when they need, rather than let it go to waste.

I already have a grid-connect solar power system. Can I add batteries?

Yes, you can. Retrofitting batteries to existing solar systems is simple and extremely common.

Retrofitting battery storage

The simplest way to retrofit batteries to an existing solar power system is to use a technique called ‘AC Coupling’. The beauty of this approach is that the installer doesn’t touch your existing solar wiring. They simply connect the battery into your home’s existing 230V AC circuit.

The Tesla Powerwall 2 battery is an example of a modern battery storage system that uses AC Coupling. One of the many advantages of the Tesla Powerwall 2 is that it can be added to literally any solar power system which is one reason for its undoubted popularity.

Basic layout of an AC coupled solar and battery storage system

The other method is DC coupling with one of the main benefits being high efficiency battery charging. The main difference between AC coupling and DC coupling is that with DC coupling you need to have a hybrid inverter in addition to the battery.  Batteries that use DC coupling include the LG Chem RESU and BYD.

What’s the best size solar system to power my battery?

We recommend that you have at least 5kW of solar panels, ideally 6.6kW, to make a standard solar power system compatible with battery storage. This is the most popular size solar system for households looking to add a good size battery system that will power them through the night and on cloudy days.

Plus, if you live in Victoria and intend to apply for the State Government’s Solar Homes Battery Rebate – currently worth up to $4,174 – it is a requirement that you have at least 5kW of solar installed.