Why a battery?

Energy storage has become very popular as power prices continue to escalate, some feed-in tariffs schemes end and as battery technology evolves. Prices of battery systems have also reduced drastically meaning more and more solar owners can store their generated energy for use at night.

Not everyone has an understanding of the reasons for all the hype about batteries. The following FAQ will help pick apart the key motivations and possibilities for installing a battery system in your home.

battery layout
Layout of a typical battery system.

Battery FAQ:

Are solar batteries financially ‘viable’?

The answer is YES. It is very possible to achieve payback within the warranty period of 10 years. Consider this, what else have you ever bought that will pay for itself before the warranty expires (and then for many years more!)

What does a solar battery do and why would I want one?

Some key reasons motivate our customers to get a solar battery:

  • greatly enhance your independence from energy companies
  • save you lots of money
  • greatly reduce your environmental impact
  • with the right system, provide blackout power protection

Is my solar system compatible with a solar battery?

The answer is YES. Despite a common solar marketplace misconception, the fact is ALL solar batteries can be compatible with any solar system. That’s because both your solar system and battery system are commonly plugged into your switchboard as two separate appliances, i.e. they don’t actually need to be plugged into each other to do their jobs.

Still not convinced? Give us a call and and we can review your existing system and tell you.


How many batteries do I need?

Every solar battery is different and they come in different sizes. The question is more accurately phrased: “How much energy storage do I need and what battery will meet my needs?”. We specialize in helping you answer these questions. Enquire today and we can use your electricity bills to tell you.

Can I go off-grid?

Sure, you can. We can do this for you right now if you have the money. But you will need a lot of money. And a generator. And constant energy management processes. And you don’t care about return on investment.

You see, once you go off-grid you are on your own. There’s no grid to help you out so if its 43 degrees in your bedroom in January and you run your 12kW ducted air-conditioner overnight…well, there is no overnight because your batteries will be flat and all your lights are out and your fridge is warming up. If you have a generator then it will get you out of trouble but start counting your diesel costs because that is going to hurt.

There are some people in remote locations who are far from the grid that absolutely need off-grid power and these people learn to manage their energy usage and have a backup generator. For those of us in the suburbs, being off-grid is a risky idea. A small off-grid system will cost around $20-40k and one that can run a family home will be around $50-100k. This is an investment of necessity not finance. The ROI is terrible .

OK, I’ll stay on the grid but what if I lose power?

This is a different scenario. You are not looking to run forever off-grid, just to keep the lights on and the fridge working in the event of an outage. This is achievable with the latest battery offerings but beware! It’s not as straightforward as slapping a battery box on your existing solar system and waiting to impress the neighbours in the next storm.

The battery modules we are selling these days are to help off-set your electricity bill. They are to take the residual solar power you generate, store it and then give it back to you when the sun has gone down. Some like the Tesla Powerwall 2, the Redback and the Enphase IQ8 system (coming soon) will keep certain circuits running when the grid is down.

These circuits, called maintenance or sustained circuits, will run some lights and a light power circuit that can run a computer or television and a fridge. It absolutely will not run your air-conditioner, your Smeg double oven or your welder. Now, you can connect several Teslas together to give you considerable backup where you might be able to run most of your gear within reason but the cost of this is nearly equal to an off-grid system.

You installed a 2kW system years ago, can I add a battery?

You can add a battery. However, a 2kW system is busy trying to run your house and there’s probably not a lot of surplus power to charge the battery each day. You will probably have to add substantially to your solar system in order to keep the battery charged and the house supplied, so systems below 5kW will probably struggle to do this. If you replace your inverter with a hybrid inverter then you can add panels to charge the battery. At any rate, you are going to have to call us to work this out.

What is ac and dc coupling?

This refers to the method of connection of battery systems to solar PV systems. With a dc system, everything takes place on the dc side of the system. You need battery inverter and a battery management system to do this. With a hybrid inverter the solar panels connect straight into the inverter as does the battery because a hybrid inverter contains the Battery Managemenst System (BMS). If you don’t have a hybrid you will need to add a battery inverter and a BMS. It’s a very busy installation doing it this way.

With an ac system, the battery system connects to the ac side of the solar. Brands like Tesla, Redback and Enphase are ac coupled. These modules connect up to the existing system without change but the battery module also contains the BMS and battery inverter. These systems are very neat.

The merits of one method versus the other can be debated but one big advantage to a dc system is that you can add panels just to charge the battery without touching the existing household PV system.

Can batteries be installed outside?

YES – at least all of the batteries in our range can. They can also be either wall or ground mounted. Be careful of cheaper brands that aren’t weather proofed…

How much will a battery cost me?

That depends on what you need. Most battery systems are in the range of $10,000 – $14,000 fully installed. Although, there are some small ones that are under $10,000, or cheap knock-offs from China that are even cheaper. Our experience is that “you get what you pay for”.

Are batteries dangerous?

Billions of dollars of R&D have gone into making the leading brands safe for consumers. Be careful of:

  • Cheaper knock-off batteries that get too hot or aren’t weather proofed
  • Someone installing one who isn’t CEC accredited, experienced or reputable!

Since 2008 we have installed both grid connected and off-grid battery systems, here are the current battery products we stock:


One of the most well-known brands of home battery currently available, Tesla Powerwall 2 has taken the whole world by storm. The first Powerwall was one of the most anticipated products ever released.

Owner and founder of Tesla, Elon Musk, also installed the world’s largest battery system for South Australia in late 2017, which uses the same technology as the Powerwall 2. The results have been staggering.

Tesla Powerwall 2, has a seriously large battery pack of 13.5 kWh which is enough for most homes (sometimes too much). Powerwall 2 also has a built-in battery inverter which means you don’t need to buy that extra bit of hardware. It is compatible with ANY solar power system.

We have installed many Powerwalls – EnviroGroup is proud to be one of the few Authorised Tesla Installers in Australia. Many of our customers have already signed up for one  and they very popular, so don’t wait longer than you should to get your own.


Enphase Energy who are world leaders in Microinverter technology also offer their own AC Battery system. Starting in 1.2kWh units, the batteries are suitable for homes with smaller energy demands.

The compact battery system is designed to be modular so it can be easily expanded, so the system size can be tailored to your home’s needs no and in the future. Providing 100% depth of discharge, you can always be sure of the amount of power being stored for use.

The lithium iron phosphate (LiFePo4) battery comes with a built in battery inverter and uses the Enphase Envoy S for energy management and monitoring. The Envoy S which measures the home’s energy usage and solar generation, directs excess solar energy into the battery for use at night.

The Enphase AC Battery pairs perfectly with new and existing solar systems using microinverters.


One of the most complete packages on the Australian battery market today. Redback is an Australian company based in Brisbane and have delivered on a product that not only provides grid-connected storage, blackout protection and modularity but is also price-disruptive. This means the Redback solution has a return on investment far more acceptable than its competitors.

The modular battery cabinet can take up to four Pylontech US2400 Lithium Iron Phosphate batteries or you can start with just the inverter cabinet on a standard PV system without the battery cabinet and ensure you are truly battery ready, adding the batteries later as you need them. Redback’s cloud based monitoring system also ensure that you have complete control and visibility over what your system is doing making your future energy smart home really smart.

We currently have a Redback system working in our showroom in Northcote. Come in and take a look.


Enquiry about battery systems today

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