Plenty of homes around Ballarat already have solar panels. Lately, more people are looking to add batteries—either to store extra power, improve backup, or get ready for going fully off-grid.

But here’s something we get asked a lot:
If you already have solar panels, do you need to rewire everything just to add a battery?

It depends on a few things. Mainly, how the battery connects to your existing system.

---

If the Battery Is AC Coupled

In this setup, the battery runs through its own inverter. It doesn’t touch the panels or your original solar inverter. It connects after everything else—on the AC side.

This is often the easiest way to add a battery to an older solar system. You’re not changing the solar wiring or panel setup, so usually no upgrades are needed.

That said, some updates might still be required. Like if:

• Your system’s really old (especially before 2012)
• New cabling needs to run to the battery cabinet
• A safety inspection is triggered by local rules (common in Victoria)

But for most people with solar already working fine, this is the cleanest path. No pulling out existing gear, no big rework.

---

If the Battery Is DC Coupled

This setup ties the battery directly into the solar side of the system. It often means swapping out your old inverter for a hybrid one. You’re combining solar and battery in one unit.

That also means:

• New cabling on the DC side
• Upgrading isolators and protective gear
• Making the whole thing meet current standards

This isn’t a quick bolt-on job. It’s more suited to new builds or full system replacements, not simple add-ons.

---

Battery Safety Rules Still Apply

No matter how it connects, a new battery has to follow safety rules under AS/NZS 5139. That covers things like:

• How close the battery sits to walls or windows
• Ventilation
• Emergency shutoff gear
• Labels and warnings

So even if the solar wiring stays as-is, the battery itself needs to be installed to current standards.

---

AC vs DC Battery Setup – Quick Look

Setup Type	Works With Older Solar	Needs Rewiring	Replaces Inverter	Good for Retrofits
AC Coupled	Yes	Usually No	No	Yes
DC Coupled	Sometimes	Often Yes	Yes	Not always

---

A lot of systems around Ballarat can take a battery without needing full rewiring, especially if AC coupling is used. But if major upgrades are already planned, or if the system’s being rebuilt, DC setups might be considered too.

Every case is different. What matters is matching the method to the system you’ve already got.