Big learnings from my first month with battery storage and more solar

As a consultant working in the field of energy efficiency and renewable energy I’ve always had a keen interest in becoming energy self-sufficient.
In 2010 I installed a 3kW PV Solar System on the 60 cent gross FiT and for the next seven years my power bills were negative, I received nice credits every quarter.
That stopped in December 2016 and forced me to rethink my situation. At that time I also realised that making money is one thing, but wasn’t I still supporting the fossil fuel industry? What was the answer?  I decided it was more solar panels and a 10kWh battery.

Juno Energy in Byron Bay installed another 5kW of LG Neon panels in June, and the LG RESU battery followed in early September. I briefly considered going off the grid completely, but decided against it because of the prospect that even 2 weeks of rain wouldn’t force me run a generator if I stayed connected.
Since then, with more or less sunny days, I’ve exported every day a maximum of 37kWh and a minimum of 9.68kWh (on a quite rainy day).
At a FIT of 16 cents per kWh, my calculations have shown that at the end of the 12 months my setup is expected to earn me between $1,000 and $2,000, after grid consumption and supply charges have been paid.
It’s not the best deal for Enova, my energy retailer, but then they are not into maximising their profit by wanting to sell more energy!
I have to add that energy efficiency has always been at the forefront of my thinking: After several retrofits over the years I’m now using between 4 and 7kWh per day.
Cooking is still gas but that will change soon, and another big user of power, hot water, is solar collectors with electric boost, rarely used. I’m considering to move over to solar power heating if and when the collector system fails.
On most days, the battery is fully charged from the night before at around 8.30 to 9.00am. I purposely had 6 panels (1.9kW) installed on the eastern roof to facilitate early recharging.
The other 10 LG panels face west to maximise energy production on hot afternoons (aircon and cooking), while the older 3kW of panels face straight north. Juno did a great job coming up with that layout solution.

On October 4 the system was put to the test: planned outage from 8am to 4pm. While everyone in Modanville was without power, I was enjoying electricity as if nothing had happened, although it took until 9.30am for the battery to fully recharge (image below).

Note that the graphs do not show the old 3kW system at work apart from the ‘Export’ figure – it will be connected to the dashboard at some point, but for now it’s reassuring to know.
It’s working in the background to provide the base load power and more, while the new 5kW supplies the battery, adds to peak power and earns cash by exporting to the grid.
Even on the one day with heavy rainfall solar generation of both systems together was about 400-500W, which I found quite amazing. This is enough to keep two fridges, the computers and a few lights going.

The lowest battery level so far was 35 per cent (which actually is 55 per cent because I set a 20 per cent reserve for unexpected blackout); this was on a cold night where I tested my 5kW air conditioner in heating mode for several hours.
All up, I’m very happy with my systems, with the professional installation done by Lightouch Electrical, and the knowledge that the system will pay for itself well before the battery needs replacement.
From a financial perspective, if you have the cash, where else would you get a sage return of 14-18 per cent? Even if you have to borrow money, at current interest rates PV Solar is definitely a good investment.
My piece of advice from first-hand experience: Get more solar panels than you think you need; get good advice on where to put them (it depends on your household usage patterns); get a local solar installer with a good track record to do the job and; yes, get a battery now if you want blackout protection and maximise your energy independence.
(By the way, the red colour in the graphs at night show very small amounts of grid energy being used before the battery takes over. I was advised that this is deliberate to protect the battery from consumption spikes).
Michael Qualmann is an electrical and electronic engineer at Powersmart Energy Efficiency. He is happy to answer any questions readers may have on 0415 875 672.


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