The million dollar question recently has been “what about batteries?”

We’ve all heard that the lithium-ion battery storage is the next big thing for Australian homes. Here’s a basic explanation of what these Lithium-ion batteries mean for you.

Why is it revolutionary?

Battery storage to complement a solar PV system has existed for some time but would involve lead-acid batteries. Lead acid batteries need regular maintenance, are very large and heavy, emit hydrogen gas and have to be replaced approximately every 5 years. The new lithium-ion batteries are lighter, low maintenance, don’t emit hydrogen gas and are guaranteed for up to ten years with a life expectancy of around 10-15 years.

The advantage of having battery storage is that you can store the power when it is generated (when the sun is shining) and use it when your panels are not generating electricity (e.g. after dark).

It should also be noted that lithium-ion is not the only type of battery on the market. There are many new and exciting technologies that can be considered, although lithium-ion is currently the most popular and advanced.

Great, so that means I should get them?

Well, in the same way, that the Tesla car is very desirable and now available it’s price of over $130,000 means that we can’t all rush out and buy one! For most of us, in-home battery storage system is still prohibitively expensive. When adding the panels, the inverter, the batteries and all the components for a 5kW system (which would probably be sufficient for a fairly energy conscious Sydney family home that remains connected to the grid but wants the benefit of being able to store solar power that is not used during the day) you’d be looking at paying around $18,000-$25,000 to set up a system with battery storage. The return on investment would be around 12-14 years and the batteries are usually guaranteed for 10 years, so financially batteries don’t yet stack up. However, the fact that the technology is now readily available hopefully means that more companies will develop similar systems (which seems to be happening already), creating a competitive and more affordable market.

But I already have solar PV and an inverter, so can’t I just add batteries?

Although possible it is not that simple. You would first need to check if your existing inverter is battery ready. This is unlikely unless you specifically requested one when you purchased your solar panel system. If it isn’t, you would need to replace your existing inverter with either a hybrid inverter (which can simultaneously manage inputs from the solar panels and batteries) or add an additional inverter which will handle the batteries separately.

However, as technology progresses more and more batteries are coming with an inverter built in, so essentially they can just be bolted on without the need to add a hybrid inverter. An example of these is the Tesla Powerwall 2 or Enphase AC Battery.  It is however always best to check with the retailer to ensure that the battery you wish to purchase is compatible with your solar system.

You would also need to consider your current solar system size. If your current system only covers a small proportion of your energy usage, you should consider expanding your system first to ensure it can produce enough power to charge the batteries, (particularly if it less than 4-5kW).

But I’ve already got the panels, so that must save me some money?

True. And in most cases when you do add on battery storage you will not need to replace your panels. However your panels
themselves are not really the bulk of the cost of a system. Your inverter and the labour involved in installing it (electricians are highly skilled and risk their lives, so they charge accordingly) are.

What do you mean ‘in most cases you won’t need to replace panels’?

For those of you who were early adopters let us first say well done! And hopefully you have been receiving the premium feed in tariff and reaping the benefits. Although your panels should still be working fine the rules and regulations have changed, so you may find that some of your wiring and panels no longer meet requirements. Please also note that if you make any adjustments to your existing system you will lose the premium feed in tariff.

So I should hold off getting solar until I can get the full package?

It is entirely up to you. However we firmly believe that it is worth getting solar as soon as you can. You will start saving on your bill and adding more renewable energy into the power supply. If you get the system size right for your energy usage then your system should pay for itself in savings within 3-6 years. So if you are going to be looking at adding a battery back-up system in 3 or more years then it is still well worth getting solar now.

If I get batteries will I be able to go off grid?

If you are setting up an off grid system for example on a rural property, then the financial case for getting solar and batteries or your system is strong. Traditionally these sorts of systems would have had a back up generator, which can be high maintenance, expensive to run and usually run on diesel, which emits nasty fumes. However if you are installing solar and batteries to a grid (mains) connected house then it is not really worth your while installing solar and batteries to go off grid, as you would need a large battery bank to get you through several cloudy days in winter and during summer days you would be generating far more electricity than you need. The batteries will be expensive and will need quite a lot of space to be stored in. By staying grid connected excess power is not wasted (because it is fed back to the grid) and you will always have the ability to buy power from the grid when you are not either generating power or are using stored power. By staying grid connected you are adding renewable energy to the mains supply. Most grid connected systems are set up to maximise the power you can use from your solar but are not set up to allow you to get all your power from your solar year round.

If I get batteries will I still have power in a power outage

Most grid connected solar and battery systems will cut out in a power outage, in order to keep people working on the lines safe. Some systems will have the option to switch off from the grid and only use your solar and batteries. There are already a lot of different options available, so you can discuss these when getting quotes.

If you are already off grid then power outages won’t make a difference to your power supply.

Read more on battery storage in our latest news section here, and here.

For even more information on batteries, download the NSW Home Battery guide here.