At Little Mountain we took the existing solar off the roof, put a bigger array up in its place and added a 16kWh Sungrow battery. It is a good job to walk through, because when storage goes in, the solar already on the roof often has to change with it.
Here is what the job involved, and how you would work out whether the same thinking applies at your place.
What we installed at Little Mountain
We disconnected and removed the existing system, then installed 28 panels for a total of 13.3kW, along with a 16kWh Sungrow battery. Some of the array went up on tilt frames rather than sitting flat to the roof. It was tested and commissioned, and the old gear and all the rubbish went with us.
Little Mountain sits just behind Caloundra, and a solar installation in Caloundra usually means a metal roof with more than one face to work with.
Replacing a solar system that still works
An older system has usually not stopped working. It was sized for how the house used power at the time, and that has often changed since.
A lot of what went on Sunshine Coast roofs around 2010 to 2012 was small, because the incentives of the day were built around smaller systems, and exporting was paid a good deal better than it is now. A 1.5kW or 3kW system was common. Since then the feed-in rate has come down a long way, and more households are running bigger loads in the evening, or planning for an EV, ducted air conditioning or a pool.
So the maths turned around. The value moved from exporting during the day to using your own power at night, and that is a different system.
If nothing is actually faulty up there, that is a separate question, and we have written about solar panel repairs and when a repair is the better call. We also replaced an older system in Buderim not long ago, for different reasons again.
Why adding a battery changes the system size
Once storage is part of the plan, the array has to be big enough to run the house through the day and put something away for the evening as well. That is the general reasoning behind sizing an array up when a battery goes in.
A battery on an undersized array tends to disappoint. It will charge slowly, and on a cloudy run it may not fill at all, so unless it is set up to draw from the grid as well, you can end up with storage that only sometimes does what you bought it for. If you are thinking about adding a battery to an existing solar system, that is the first thing to check.
Tilt frames on a low-pitch roof
Some of the panels at Little Mountain went up on tilt frames. Where a roof is quite flat, or the best-facing surface is not the biggest one, raising the panels can put them at a more useful angle to the sun.
It also uses up more roof than a flush mount does, because tilted rows have to be spaced so they do not shade the row behind. On a low pitch roof that can mean fitting fewer panels in total. Up here the pitch is often not far off where you would want it anyway, and panels are cheap enough now that the extra panels often win. So it comes down to a calculation on each roof rather than a preference.
What a solar installation involves inside the roof
Most of a day like this one is spent where you will never look at it. Cabling gets run through the roof cavity. The switchboard gets opened up and whatever work it needs gets done there. Isolators and labelling all have to go in properly, because that is what the paperwork and the next sparky depend on.
What happens to the old solar panels
The old panels, the old rail, the offcuts and the packaging all left the site with us.
It sounds like a small thing to mention, but a system replacement generates a surprising pile of material, and it should not become your problem.
Solar installation across Caloundra and the Sunshine Coast
We are a local solar company based in Caloundra, and we install solar in Caloundra and right across the Coast, including Little Mountain, Currimundi, Buderim, Mooloolaba, Maroochydore and Noosa.
If you are thinking about a battery and you are not sure whether the solar you have got will keep up with it, I am more than happy to come and have a look and tell you honestly either way. Sometimes the answer is that what you have is fine as it is.
You can request a quote here, or please don’t hesitate to call or email.
Justin Zerna
Owner, AHJ Trade Services
0492 910 232
justin@ahjtrade.com.au
