Breaking down the true costs, benefits, and backup potential of solar batteries.

Whether you’re a homeowner or a business owner, you’ve probably wondered:


  • "Should I get a solar battery?"
  • "Are solar batteries worth it?"
  • "How much more will I save with a solar battery?"


In this guide, we’ll get into the savings and benefits of solar batteries. But first, let’s talk about something even more important: energy resilience.

 

Solar batteries and their impact on energy resilience


Without a solar battery, your solar system will not work when the grid goes down.


Yes, even those beautiful panels on your roof won’t do a thing.

Here’s why: New Zealand regulations require grid-tied solar systems to shut off during outages. This prevents power from flowing into the grid and potentially harming workers repairing the lines.


But solar batteries? They allow your system to keep running when the grid is down.


So, ask yourself: Do I need power resilience for my home, business, or family?


  • If your answer is a resounding YES, great! We can help you by designing the ideal solar system that ticks all the right boxes, including price.
  • If you’re unsure, keep reading—we’ll help you weigh the benefits.

 

How solar batteries enable partial or full home backup when the grid is down


Approximately 30% of NZ solar systems have batteries. And most of them keep things operational when the grid goes down, but not all.


Some solar batteries connect directly to the solar inverter. These systems are titled ‘Hybrid’ systems.

Other batteries have the inverter and backup functionally all in house. (The Tesla Powerwall 3).


Most Hybrid Solar Systems have two outputs.     

 

1. The grid side. This output only works when the grid is on.

2. The backup / crucial loads output. This output continues in a power outage, assuming the inverter is capable of isolating itself. (Most are).


Until most recently, the backup output was only capable of delivering 20-60% of a typical homes power requirements.

But in the past couple of years, inverters have become both cheaper, and more capable.

 

The reality of whole home backup


In 2023 & 2024, most of the inverter manufacturers released inverters than can deliver around 45 amps of continuous power deliver in a power outage.

45 amps adds up to more than 10kW of continuous output.


Before 2023, solar owners were lucky to get 5kW continuous output from their systems during an outage.

But 10kW... That's a ton. Not many homes that pull more than 10kW for an extended period.


These 'juicy' systems aren't cheap - but as power prices rise, they're starting to make a lot of sense.

In 2026, even a $40,000 system is likely to save $5,000 per year, providing an ROI of ~13%, and a payback period of ~7 to ~8 years.

 

Everyone knows solar saves you money


It's all pretty complicated, but lets give it a crack.


Let’s assume a 17-panel solar system.


  • 17 panels installed in 2026  = approximately $14,000
  • 17 x 460w panels = 7.82kW peak power output
  • Annual production = 10,700 kWh


If you're not home during the day, but able to heat some hot water (or a spa pool), you'll probably use about 35% of the solar - without a battery.


The savings are tied directly to your power rates. in 2026, kiwis are paying about 36c for power, plus GST.


  • 35% of the solar equates to some free power for the home owner! About $1,550 in savings for the year.
  • (35% of 10,700kWh multiplied by 41.4c).


And how about the rest of the solar? The energy that the home doesn’t use?

Well, the power company buys it from the home owner.


As at Feb 2026, Genesis pays 12.5c. Powershop pays 13c. Meridian pays 17c. Ecotricity pays 21c at peak times. Octopus pays 40c at peak times in winter.


So, let’s take a conservative average of 18c.

  • 65% of the solar gets bought by the home owners power company!
  • Solar buyback credit -  $1,250 over the whole year.
  • These ‘solar buyback credits’ are applied directly to their energy bill.
  • (65% of 10,700kWh of solar generation, multiplied by 16c).


Savings come in the form of free power, and solar buyback credits.

Adding the buyback credits above of $1,250 and the free power of $1,550 we're looking at savings of $2,800 per year, without a battery.


Conservative estimate of  savings without a battery:

Spend $14,000 to save a total of $2,800 annually.

Assuming no inflation, the payback period is around 5 years.


Adding a battery, conservatively:

Spend $24,000 to save approximately $3,500 annually.

Assuming no inflation, the payback period is 8.57 years.

 

More on how batteries increase your savings


Most kiwi’s think solar isn’t worth having if most of the energy gets sold to their energy retailer.

But as seen above, even if you're selling 65% to the retailer, solar is a no brainer!


In fact, some solar companies make it their main sales pitch. “You must get a solar battery… Selling power to the grid is worth pennies… Don’t waste your money on solar without a battery…”


But we beg to differ.

Hear us out.


Batteries save you more money by storing energy during the day, to use it at night; or on a cloudy afternoon.


But how much more? Is it a lot more? A little more?

The answer is….


A LITTLE MORE.

 

How a Battery saves you a little more


Now, let’s talk about how a solar battery could save you a little more.


The idea is:  If your power company buys back energy at $0.16/kWh, and your rate is $0.38/kWh, a battery saves you the difference:


  • $0.33 - $0.15 = $0.22 per kWh stored
  • For a 12kWh battery costing $15,000, storing and discharging an average of 10kWh/day would save you about $2.2/day—or $803/year.
  • A 12kW solar battery should cost you about $15,000.
  • At that rate, assuming no inflation, it would take 19 years for the battery to pay for itself.
  • Good batteries are expected to last 15 – 20 years, but are only warranted to have a capacity of 60 – 80% at year 10.


You can save more by charging your energy off the grid during off-peak times


Many solar companies are selling the benefit of charging your battery when power is cheap, and discharging when power is expensive. This is a great idea! But -most batteries only allow 1 full charge and discharge per day in the terms and conditions of their warranty. So - if you 'trade' energy, you may void your warranty. But faster battery degradation is a certainty once you start trading energy.

Also - if you buy at 20c and consume during a period where your peak rate is 45c, the benefit is 25c.

12kWh x 25c = $3  a day.


Is it worth trading energy, to save a maximum of $1,095 per year, if its going to decrease the life of your solar battery by up to half?


The life expectancy of the battery is about 15 years. If it ends up lasting only 8, because you've earned an extra $1000 per year from trading energy, is it really worth it?

 

If you want a solar battery, we’ll help you get a great one!


And we’ll be incredibly transparent with you on the savings and payback.


We’re not saying ‘don’t get a solar battery.’

We’re simply providing a framework for you to evaluate the cost and benefit.

 

Is there another way? Can free power hours be utilized?


  • Some energy retailers offer discounted power during the night hours.
  • Most batteries let you set charging and discharging times, so you could charge your battery during these times.
  • While these plans often come with higher daytime rates, solar users don’t buy much daytime power anyway—so the savings can add up.
  • We can help you model this to see if it’s worth it for you.


Is It Safe to Charge a Battery at Night?


Many of our clients raise concerns with battery safety. They wonder if their battery will catch fire.

Fact is, the risks are minimal, almost zero. There’s definitely more risk that a cheap phone charger from Temu will cause a fire in your home.

However… While the risks are practically zero, there is still a risk. So, here’s the real question:


Are you comfortable having a battery charge at full capacity while you’re sleeping?


Your answer depends on your appetite for saving money, and the risks you're willing to take for an extra penny!

 

Conclusion: Should You Get a Solar Battery?


We’re not saying “don’t get a battery.” But it’s important to weigh the costs and benefits carefully.

If energy resilience matters to you—or if you want to explore all the ways to save—we’ll guide you every step of the way.

Solar subsidies - likely ... to hurt your back pocket and stress levels

By looka_production_130270016 • March 19, 2026
Because supply and demand is the guiding principal behind prices in every market...

Why We Can’t Size Solar Batteries Like The Aussies Do

By looka_production_130270016 • February 7, 2026
Why We Can’t Size Solar Batteries Like The Aussies Do Most kiwis want solar to reduce their power bills, and mostly – their winter power bills. And most Kiwis tell us – “We want a solar system that charges up the batteries during the day so that we can heat our home at night.” News flash: Yeah........... Sorry - that’s not going happen aye. Here’s why. Everything You’ve Heard About Sizing Solar & Batteries Is Probably Wrong (For NZ) When you jump online and search about solar, you’ll find information from Bloggers and YouTubers in parts of the world with entirely different energy demand patterns. Think about Australia for a second. 99% of homes in Aussie use tons of power in summer, which is conveniently when they generate the most solar. Our clients often come to us with the idea that solar + battery means very little grid use with the potential for 'off-grid in the city'. In Aussie, that's almost possible! But not here, because most kiwi homes use more power in winter, than in summer - which is inconveniently when solar systems produce ~50 to ~70% less. We’re left with two conundrums: in summer, you can’t make the most of a big battery… and in winter, you can’t charge one. Batteries Should Be Sized According To Your Spare Winter Solar This is the main point. Read the rest of the blog for more insight. ‘Nuf Said. You Won’t Discharge A ‘Uge Battery In Summer Let’s say your solar system generates ~40kWh per day in summer – (typical for a 20 panels system). But your home uses ~25kWh per day. There’s a 15kWh difference between what your home uses, and what you’re generating. So if you don’t need that spare energy, what’s the point in storing it? * Whether you have a huge battery or not, if your home doesn't use the spare solar, you'll be selling that 15kWh for about 17c per unit, which adds a $2.55 credit to your power bill EVERY day. You Don’t Need Much Storage In Summer If your home uses ~25kWh on a typical summer day, the question is: how much of that energy demand occurs after the sun goes down? ‘Cos the reality is – most homes don’t use much at all. After 8pm in summer: … You’ve done the cooking … Used a bit of aircon in the arvo … Your hot water’s steaming … The beers are cold … And your TV uses 100w So on a 25kWh day, your home might only pull ~10kWh between 8pm & 8am. … So, with these rough summer calcs, with 20 panels, most people can only make the most of a ~10kWh battery. C’mon – Surely It Makes Sense To Have A Big Battery In Winter? Yeah, I know that’s what you’re thinking. Everyone thinks that. You get home from work... Crank the heating till 11pm, and then ‘sip’ the heating until everyone leaves the next morning. So of course, you need a big battery to power all that heating. But wait… Solar Sucks In Winter - Sorry ‘bout it. That system we spoke about, those 20 panels; they’ll generate about 40kWh on a typical summer day. But in winter, you’ll be lucky to get 30kWh. But most homes don’t have a 35 degree north facing roof. So 20 panels generate closer to 20kWh per day. And this hypothetical home we’ve been talking about (that uses 25kWh per day in summer), probably pulls 50kWh per day in winter. And of that 50kWh, 15kWh is probably pulled during the 9 – 5. Fridge, freezer, hot water heating, maybe a spa – whatever it is – even with nobody home, there’s still power use during the day. So, shit – of the ~20kWh these 20 panels are spitting out, more than half of it is chewed up by the homes base loads. The difference goes into the battery. And what’s the difference here? ‘Bout 10kWh, if you’re lucky. … So even though the house uses 50kWh per day in winter, there’s no point having a battery bigger than ~10kWh. It simply won’t get charged. You’re The Worst Salespeople Ever No, we’re not. We’re just saying it like it is. In summer, you couldn’t possibly use all of your solar. And in winter, you couldn’t possibly charge a huge battery. But you can still save a shit ton with solar. And the good news is, you don’t even need a battery to eliminate most of your summer bills. Read this . And this . And watch this. But if you want to reduce your winter bills, you’re going to need a battery. If it adds a year or two to your solar-system payback period, it’s nothing in the scheme of things. Especially when you consider the blackout experience. (Its awesome these days)! So, What Do I Do? Prioritize north, if you can. A north roof with a pitch of 15 to 45 degrees is ideal. North produces the most energy in winter, which gives you the best hope of charging a battery. If your roof has some north, and a bit of something else – prioritise north AND west. We love west, because west produces energy until the summer sunset, which is when you might want to cool your home. If your roof is East and West; look very closely at the winter production estimates, because most east-west systems struggle to charge even the smallest batteries in the 3 coldest months of the year. You Didn’t Answer My Question – How Much Storage Do I need? … Sorry, here’s the framework. Subtract your winter day time energy use from your winter solar production. The answer reflects the size of battery you should consider. You could buy a little more, but again – consider your summer evening loads, and ask yourself – do you want to spend a few grand extra (or more); just for it to be a pretty box on the wall providing little financial benefit? Does Equity Solar Brokers Support Solar Batteries? Heck yes we do! We love seeing our clients get batteries. About one third of them get batteries with their solar purchase. We’re not against batteries. We are obsessed with helping kiwis get a great return on their investment. We achieve that through smart solar system design and anonymous quote procurement, which is our leverage to getting sharp solar quotes. Everyone has a different solar objective - and we're all ears. Can't wait to hear yours. In a time of rising power prices and grid instability, batteries are awesome. And guess what – we’ve never had a client regret buying a battery. One client called to tell us they had a 2-day powercut, but only found out when the neighbors swung by. Priceless. Need a hand with system design? That’s what we do best. And we’ll get you the best quotes in the market while holding your hand every step of the way. Chuck your deets below, and lets do this.

What Happens After You Say “Yes” to Solar?

By looka_production_130270016 • January 24, 2026
Before your details are shared with a solar company, here’s what you should know about what happens next — and why this process doesn’t move at Uber Eats speed.