Home battery storage (solar systems)

If you haven’t yet viewed the videos and still would like to I have captured them and could share them with you on OneDrive. Obviously I would need an email address to send the share link to, one file is 48 MB and the other 297 MB in size. Anyway let me know if you are interested.


Thanks for the offer, but no need thanks, as I’ve read quite a bit about the PW2 in recent months. About the same cost for twice the PW1 storage capacity, and one option has an inbuilt inverter, so it is much more financially viable now. In some areas with high cost per kWh, such as SA, it is definitely worth installing right now, particularly in conjunction with new or existing PV panels.

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For those who are interested, Energy Matters has a solar calculator which is also worth looking at should solar be considered. We used it many years ago before buying to see what sized system we would need and what varying sized systems would do to our power bill. Even though we used the website, we didn’t use them for our PV solar install.

Interesting enough though, their calculator was within 5% for the average annual generation it calculated for Brisbane (and for our 6.5 years worth of data)…so it is reasonable reliable for SE Qld. Not sure how reliable other parts of Australia are but assume that it should be just as good.


It’s based on global solar radiation data from BOM, NASA etc, so should be as good as the data is. However, the data is estimated from satellite images for much of the country, away from the capitals, so there will be some local variations. The nearest station to here for where it is estimated, about 10km away, does show some differences, for the odd day I have looked at it. One of these days I might get around to reducing/converting all my radiation sensor data to see how it compares to the satellite data on longer time scales.

Disclosure- I moderate/administer EM’s Forum.


The Powerwall 2 DC version is no more, and the AC version will be delayed some more, some say until June.
Ron Brakels in Finn Peacock’s blog has a bit to say about it here:


Here’s a random thought:

Why not combine home power storage with your electric car. The car’s battery can be used as power storage when not in use (most of the time) and have the power ready for you when you need it.

What are people’s thoughts on this idea?


This has been extensively discussed on solar forums, and is likely to happen in the future. Currently it isn’t really possible as the equipment to do it is not available.
One significant issue is that many people’s cars are not at home during the day, so can’t be charged from their rooftop solar array, except perhaps on weekends. With the current grid mostly supplied by dirty fossil fuel energy, especially at night when most people would be charging, I’m not convinced it would be a great step forward. Charging at workplace car parks is a possibility, if workplaces are willing to install PV arrays, then the house could be powered with clean energy at night from the EV’s battery.


It looks like the blogger I linked above wasn’t as well informed as he might have been, as Tesla have announced that the Powerwall 2 AC will be available in Australia next month. An article covering the Oz launch by Elon Musk’s cousin appeared on RenewEconomy today here: http://reneweconomy.com.au/tesla-launches-powerwall-2-says-all-solar-homes-will-have-storage-53696/


Found this from Canstar Blue whilst “browsing” around . Lists the different makes of home storage batteries available .



Thanks for your ideas, @gordon. I understand we are in the messy transition period right now and so it would be difficult to use such a system tomorrow. Your last comment is what I was thinking about in the long-term.

When everyone has finally converted to clean energies, you could charge anywhere and discharge anywhere. I’m glad this is being heaviuly discussed in other forums; I barely have time to keep up with this one let alone to start delving into others!


Things are not looking for good for Aquion: https://www.pv-magazine.com/2017/03/09/aquion-files-for-chapter-11-bankruptcy/

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Cost less than a regular roof? I’ve always found that very hard to believe… maybe they meant less than the most expensive alternative they can think of! Less than Gold plated Colorbond perhaps? :wink:

Bloomberg New Energy Finance reckon they will cost ~20X as much as regular asphalt tiles (common in the US)


Hi @gordon

Just added a link on another discussion about the pricing and warranty on the Solar roof tiles, link is here:

Solar and Grid Connections


Solar battery installs are surging.


The AC version is available in 2018. And it’s control system (Backup Gateway 2 for PowerWall 2) handles three phase as well as single phase.


We’ve had solar panels since 2009 and I keep the quarterly figures for daily averages of - kWh we make in total, kWh we export to grid, kWh we import from grid, kWh we consume in total.

Winter is our low useage time of year (averaging between 12 and 14 kWh per day). If we had a battery system we would still have a net export to the grid in this season from our little solar system.
Only in summer would we still need to import a little, average 2 to 8 kWh per day depending on how hot the summer is.

To store enough kWh to handle one day in summer entirely from battery I reckon we’d need battery with capacity to discharge 25 kWh.

Question: to allow for a period of consecutive cloudy days, what is the recommended multiplcation factor?


25kWh is a big investment.

I ran our house through the calculator on the solarchoice web site.
There is no one size fits all.

Choice has a very basic guide most of us may have seen before.

For a hybrid system if you need to cover 1, 2 or 3 cloudy days in summer have you considered that you will need enough surplus solar when the sun comes back to run your house and fully recharge your battery at the same time?

You also loose feed in credits when charging so perhaps also need to consider the difference between your feedin tariff vs purchased power price. The smaller the difference the longer the payback on the battery.

I used the BOM web resource for my nearest weather station to obtain solar data to assess what was statistically relevant to our location.



Another relevant link from my ‘go to’ source.