{"id":101636,"date":"2026-09-09T06:10:42","date_gmt":"2026-09-08T20:40:42","guid":{"rendered":"https:\/\/www.solarquotes.com.au\/blog\/?p=101636"},"modified":"2026-09-09T06:10:31","modified_gmt":"2026-09-08T20:40:31","slug":"unreliable-backup-power-mistake","status":"publish","type":"post","link":"https:\/\/www.solarquotes.com.au\/blog\/unreliable-backup-power-mistake\/","title":{"rendered":"Unreliable Backup Power: The Mistake Everyone Keeps Making"},"content":{"rendered":"

\"3<\/p>\n

We’ve seen a big change in the solar industry recently. With batteries becoming standard, everyone is getting backup.<\/p>\n

The problem is that poor design and sales misunderstandings are leaving people, especially three-phase customers, with a total oxymoron: unreliable backup power.<\/p>\n

The good news is that solar power is being installed in huge numbers, and the attachment rate for batteries has gone through the roof. Some companies are even giving up on solar-only installations; if the customer doesn’t want a battery, the installers don’t want the job.<\/p>\n

However, a few installers and customers alike have been caught out with an embarrassing lack of capacity.<\/p>\n

Single Versus Three-Phase<\/h2>\n

I’m told that 80% of National Electricity Market customers have a single-phase supply, while two-phase & split-phase aren’t common, three-phase is becoming the new normal as houses grow and EVs proliferate. If you’re not sure what you have, read this explainer.<\/a><\/p>\n

The vast bulk of appliances are single-phase, but on a three-phase property, they’re spread over three adjacent supplies, and often the house will be wired in three segments because the poles-and-wires network wants loads balanced within 5 kW if possible.<\/p>\n

It’s not uncommon for a three-phase house to have a modest 5 kW single-phase battery backup system. They’ll supply 21 Amps, and there’s nothing wrong with that. However, as prices have fallen and appetites rise, more people are opting for full three-phase backup because it can save the cost of rewiring a third of the switchboard.<\/p>\n

Things get awkward, though, when a numpty who’s used to selling 8 and 10 kW single-phase systems doesn’t automatically triple their recommendation to customers with a three-phase house.<\/p>\n

10 kW Three-Phase Inverters Are Junk<\/h2>\n

The headline number isn’t the only factor to consider, as we\u2019ve recently outlined,<\/a> but the thing to remember is:<\/p>\n

A 10 kW single-phase inverter is pretty gutsy.<\/p>\n