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Solar battery storage in Australia 

Solar battery storage for existing solar installations (and new ones) 

Solar battery storage is what we all want to use to store all our surplus solar production during the day and then use it up at night. One of these days, power prices will have risen enough, and battery prices will have fallen enough for it to make very good financial sense to add batteries to your solar installation. Perhaps we will see state or federal governments offering battery subsidies soon. We can only hope.

Let's look at the most common request we get....

I want to get solar now, and be battery-ready for the future.

It is certainly true to say that every solar installation now, or in fact, ever installed, is 'battery-ready'... but the devil is in the detail. We tell people that the ever popular Fronius Primo does not have a battery interface and are met with disbelief because the customer has been told time and again by solar sales reps that it is 'battery-ready'. So let's look at what that really means.

Interpretation of 'battery ready' - Version 1

If by 'battery ready' you mean that you don't want to spend $1400 or so on any additional hardware in the future, you simply want to buy some batteries when the price is right and hook them up, then you need to be looking at a HYBRID inverter, plus its 'Smart meter'. You can tell it's a hybrid because it has a postive and negative terminal on the bottom of the inverter marked 'Battery'. You won't find such a thing on a Fronius Primo because it's not a hybrid.

Huawei FusionHome range of single phase inverters (2kW, 3kW and 5kW) are all hybrids. Fronius have one of the only 5kW 3 phase Hybrid inverters. The Symo Hybrid, and it costs $1300 more than the regular Symo.

Goodwe make an excellent single phase hybrid inverter (pictured below) and it costs $990 more than the regular Goodwe, which makes it dearer than Huawei and therefore, we would suggest, go Huawei.The Goodwe smart meter and installation will cost you $200.

Now, just add batteries and a cabinet to put them in.

Interpretation of 'battery ready' - Version 2

However, if you don't mind spending some money later, on some additional hardware, then you are good to go. Buy any inverter you like and add the rest later. We are expecting a lot more products to start arriving, but already Goodwe have got off to a fantastic start.

Their DC coupled product (GW2500-BP) is connected in between the solar panels and your existing inverter. It has a meter (single or 3 phase) and the batteries connect to it. During the day when your panels are producing, it will take surplus solar power and charge up the batteries, and then as the sun goes down it sends a 360V keep alive voltage to the existing inverter and sends the stored battery power to the existing inverter as and when it's needed. As far as the inverter is concerned, the sun must still be shining because it's getting power from what it thinks are its solar panels. This very clever unit costs $1400 and the meter plus install is $200 for single phase and $400 for three phase. Then just add batteries.

Staying with Goodwe, they also have an AC coupled inverter. This connects directly to the switchboard and has a smart meter (single and 3 phase). It intercepts solar power that would have been exported to the grid and stores it in the batteries and releases the power after 4pm. This costs $2,160 + $200 for the single phase meter and installation and $400 for the 3 phase meter and installation.

The Smart Meter

The most important component in the battery scenario is the meter. It monitors the power consumption in the house so the rest of the system knows whether to charge the batteries or release the stored power.


Everyone has heard stories of exploding mobile phone and laptop batteries, and most of us are aware that these are made of Lithium. LiFePO4 stands for Lithium Iron Phosphate, are the only type of Lithium battery chemistry that we consider safe for use in solar battery storage.

BYD as shown in the picture below connected to the Goodwe Hybrid is the World's leading brand (yes, bigger than Tesla). Their 2.5kWh battery costs $1750 at the moment, and you can add up to 4 per cabinet. The cabinet costs about $900. Zero maintenance, 10 year warranty.


The cost benefit analysis

Once you have got everything you need, you will find that you have spent $10,000 for 10kWh per day of battery storage. As long as your SURPLUS solar panel power is sufficient to charge up the batteries (approx 11 kWh per day will do it) then it's just a matter of doing some maths.

The value of each kWh of battery power is the price you pay for power MINUS what you would have been paid for your surplus power by Synergy if you hadn't got batteries.

So, in 2017, that $0.2647 MINUS $0.0714 = 19.33 cents

10 units a day x 19.33 cents = $1.933 per day or $705 a year.

If power prices rose 5% a year you would have made $10,000 back 11 years later.

Sure, the batteries might still be going strong for quite a lot longer than their 10 year warranty, but it's not very exciting is it?

Now let's fast forward a couple of years. Let's say the 10kWh battery system has dropped from $10,000 to $8,000 and the politicians have hiked power prices to $0.40 a unit (that's what they are paying NOW in some of the Eastern States) and they are giving you 14 cents for surplus power. That a difference of $0.26 per kWh, $2.60 a day or $949 a year.

Now, if electricity prices increased by 5% a year, the payback time on $8,000 is a bit over 7 years. It's better, but it is still not very exciting. We think that most people would be ok with a 5 year payback, and frankly, whilst things can change rapidly in this industry, it's hard to predict when the time will be when a 5 year payback is achievable.

 is the web site for Good Day Mate Pty Ltd trading as SOLAR4EVER Company registered in WA on 26th October 2008 (A.C.N.133884938)

Contact Detail :

Telephone : (08) 6102 2527