We’ve got some cracking data from a solar setup we finished off a couple of years back, just a stone’s throw from Ballarat. Here’s the gear we used: solar panels of around 50 kW, a battery bank of lithium batteries with a total of 70 kWh, and a 30 kW inverter. Diving into the performance data, I took a squiz at the 24 hours in June 2023. During this stint, the solar panels chucked out a low of 50 kWh, while the generator peaked at 60 kWh. Household consumption was 90 kWh, and the battery’s charge cycled from flat as a tack at the start of the day to chockers at 100%, then back to flat by knock-off time. And get this, that day clocked in as the lowest solar generation for the whole year.
This sparks a fair dinkum answer to the question: Can an off-grid solar system in Ballarat, manage without a backup generator? Bloody oath, it can. The numbers show we just need to beef up the solar panel setup from 50 kW to 100 kW. Now, you might reckon that sounds pricey. But nah, it’s not as bad as you’d think. I’ve been banging on for ages that a 10 kW off-grid solar system fits the bill for your average family. Double the solar panels without beefing up the inverter and battery, and you’ll see it’s not a wallet-buster. Most of the outlay gets offset by the STC rebate. Plus, don’t forget the dosh you’d drop on a generator. Slapping on an extra 10 kW of panels might set you back just $4,000 extra for a 10 kW system. Meanwhile, a 10 kW generator will run you for more than $5,000, plus the juice it guzzles. A 20 kW setup is a solid choice if you kit it outright, especially with an inverter that can handle twice the solar panel capacity it’s rated for.”