A lot of people assume that once you've got solar panels, you're covered if the power goes out. It's an easy assumption to make, and an important one to get right, because for most systems, it's not quite true.
Why solar switches off during an outage
When the grid goes down, a standard grid-tied solar system switches itself off too, even during the day, even with the sun shining. That's not a fault, it's a safety feature. It stops your system from sending power back into lines that linesmen might be working on to fix the outage. So without a battery, solar panels on their own don't keep your lights on when the grid drops out. This catches a lot of homeowners by surprise, understandably. It seems counterintuitive that a system generating its own power would go dark right when you'd want it most.
What changes if you've got a battery
A battery changes this. Instead of relying entirely on the grid, a system with battery backup can disconnect from the grid safely and keep running on power that's already stored, rather than shutting off completely. That's what gives you continued power during an outage, not the panels themselves, but the stored energy behind them. How much of your home stays powered, and for how long, depends on the size of the battery and what's set up to run on it. It's not automatically your whole house for days on end, it's a question of what you've planned for and how the system's configured.
It's not all or nothing
This is worth spelling out because it's easy to picture backup power as either fully covering the house or not helping at all. In practice, most setups sit somewhere in between. Some households prioritise keeping the fridge, some lighting, and the internet running. Others plan around specific needs, like medical equipment or a home office. The point is, it's a decision you make when the system's designed, not something that just happens automatically once a battery's involved.
Worth checking it actually works
Once backup is set up, it's worth understanding how it would actually behave during a real outage. Ask whoever installs your system how the switch-over happens, whether it's automatic or needs input from you, and how you'd know if something wasn't working the way it should. That's not a question people think to ask upfront, but it's one worth having answered before you need it.
What to think about before you decide
If outages matter to you, whether because you've been caught out before, or you live somewhere prone to them, it's worth having that conversation early, not after your system's already been sized and installed. What you actually want covered during an outage should shape the size of the battery and how it's wired in, not the other way around.
Two different jobs
Solar and battery backup solve different problems. Solar is mostly about your day to day power bill. Backup is about what happens on the handful of days a year when the grid itself lets you down. Both are worth having, but they're not the same thing, and it pays to know which one you're actually getting before you commit.
Want to know what backup would actually look like for your home?
Steel Solar & Electrical has spent close to two decades in the electrical industry and well over a decade in solar, and we talk homeowners through exactly what a battery would and wouldn't cover before anything gets installed, not after.
steelelectrical.co.nz | 0508 2 SOLAR
