A beginner’s guide to understanding solar battery basics and benefits.

Lil' Ol' Jimmy has a lot to learn about solar batteries

🔋 Buying a Solar Battery System in NZ? Here's What the Solar Bros Won’t Tell You

Going solar, huh? When it comes to batteries, the real power is in the details.

This article is your no-fluff guide to getting a battery system that actually performs — in Auckland storms, Waikato brownouts, or Christchurch's cheeky pre-Christmas roast.



☀️ Plan Ahead or Pay Later

If you're installing a hybrid inverter today with dreams of adding a battery “sometime later,” make sure “later” doesn’t mean five years from now. Why? Batteries and their compatibility with other brands move fast. By the time you’re ready, your hybrid inverter might be as useful as a fax machine at a Zoom meeting.


Golden rule: add the battery within 1–2 years max. If you wait too long, you might not be able to find compatible battery modules without replacing the inverter too. That’s not futureproof — that’s expensive.


If batteries don't currently make sense for your wallet or home, don't get a hybrid inverter for the 'maybe' battery in 5 years.


📦 Battery Capacity Isn’t Just a Number

Let’s say you’ve got a 10kWh battery. Does that mean you can use 10kWh? Nope. Most batteries hold a little back to preserve their lifespan. Some let you use 9.5kWh, others only 8kWh. That difference adds up over 10+ years.

Also — some brands quote total capacity, others quote usable. Always double check.



⚡ Inverter Output: The Power Bottleneck

This is the cap on how much power your system can actually push into your house at any one time.


A 5kW hybrid inverter can only output 5kW continuously, no matter how big the battery is. Think of the inverter like a coffee straw — you can have a swimming pool full of latte (battery capacity & output rating), but if your straw is tiny (inverter limit), you’re not sipping fast.


This is where brands like Sungrow, Tesla, Solax and SigEnergy shine — their inverters push out more juice, faster.



🔌 Battery Output: Don't Get Caught with a Shallow Pool

Not all batteries are created equal. Some can keep up with your appliances — others collapse when you turn on the jug.


Let’s talk about a real example from the Waikato. One homeowner recently bought a battery setup from ‘NZ’s most trusted solar installer’. They bought a 3-stack GivEnergy battery, which is advertised as the #1 battery in the UK.


On paper? 10kWh. Sounds alright. But the shock came when they learned it can only output 3.6kW continuously. That’s 230v at 16A. Translation? In their first power cut, they had two power cuts. The grid went down, and then the inverter and battery went down. Not ideal.


Seems crazy because there’s  another battery out there called the Alpha. Alpha was Australia’s most sold battery in 2024. It’s cheap as chips compared to almost everything else. Their 8kW inverter + battery combo can do 8kW continuous, and 12kW for 30 seconds!


Most batteries on the market easily push out 5kW, but not all.  5kW continuous is enough so you can turn on your jug, while your Wi-fi, lights, and a cheeky heat pump keep on keeping on without a huckup.


We’re all for less capable options in the market place. But call (and price) it for what it is. If your solar battery can’t power an air-fryer, what's the point of living?



⚙️ Switchover Time: When the Grid Goes Down, How Fast Do You Bounce Back?

This one’s a biggie. When the grid cuts out, how quickly does your battery jump into action?

  • Sigenergy: 0ms. You won’t even notice the lights flicker. Mint price too.
  • Tesla Powerwall: About 1ms. Still seamless.
  • Sungrow: Basically the same as Tesla.
  • GivEnergy: Up to 10 seconds. That’s long enough to trip devices and maybe even your Netflix download.
  • Solis: Same as GivEnergy, but for about half the price! (The battery options on the market with Solis are great value too!! The Dyness Powerbox pro is a great performer.)
  • Alpha: Up to 20 seconds, but not to worry – it’s a fugg’n good price and you can't expect everything you want in a cheaper alternative.


Tauranga story time:

A bloke down down the road installed the latest Tesla Powerwall. His house kept ticking along just fine when a power pole got in the path of a boy-racer with red ute. Even though the man with the Tesla Powerwall was roasting chicken, he didn’t need to turn off the oven because he knew 10kW continuous output was more than enough to carry on like ol’ mate had his Low-Lux Ute impounded before the power pole got in his way.


🤖 AI Charging? Kinda Nice, Not Entirely Necessary

There’s a lot of hype about AI integration and how it will make money for you while you sleep.

But we think the extra pennies might not be worth the damage to your battery.


Remember Solar Zero? (Farewell Solar Zero – your service would have been great for literally HALF of our pipeline who have negative home equity and can’t get green loans).


Part of Solar Zero's business was making money off energy trading. But they found the numbers didn't stack up as well as they hoped.


Most modern batteries let you set a charge/discharge schedule. That’s where the real win is in NZ. For example:

  • 9PM–7AM: power is cheap — discharge to 5am until its empty, then charge from 5am to 7am.
  • 7AM–11AM: expensive — battery discharges.
  • 11AM–5PM: solar kicks in — battery chills and charges.
  • 5PM–9PM: everyone’s home, power’s pricey — battery discharges again


Set that up once. Update it if your power plan changes. Done.


And then there's SigEnergy. 

The latest kid on the block, with immensely good reviews and a solar-installer following that grows larger by the minute.


SigEnergy has employed Chat GPT4 trade its customers energy like two 8 years olds, each with a dollar mix from the four square.

AI is learning the patterns of the home owner to build a unique charge and discharge schedule that  maximises energy-trading-revenue while simultaneously decreasing reliance on grid power.


🔍 Final Word: Don’t Fall for the Flashy Brochures

There’s a lot of noise out there. But when the power cuts and your kids are forced to choose between the PS5 and playing outside, you’ll know if you chose the right system.


So don’t just look at battery size. Look at:

  • Continuous power output
  • Switchover time
  • Inverter size. This one gets missed often. 
  • Forget it – our mission is to simplify the entire process. Leave us your deets and you won’t have to worry about any of this complex jargon.


And hey — GivEnergy  is in the market now. That’s good for competition. But don’t let a sales pitch from the only people selling it in NZ sway you like the sleep after a few too many cold ones. Ask questions. Check the numbers. Compare it to Sigenergy, Tesla, Sungrow, Alpha  — and see which one ticks all the right boxes, including price.


Solar isn't like a one-size-fits all flexi fit cap. Use our service and get the ideal solar system for the ideal price.

 

This blog reflects our ultra-professional and super biased opinions based on actual market feedback, real world data sheets, tons of recent chinwags with over 30 solar companies, real-world performance, and what we’ve seen on rooftops from Auckland to Christchurch. All product data is accurate to the best of our knowledge at the time of writing. We’re not here to throw shade — we’re here to shine a light.

Any references to other solar companies or products are general in nature and based on publicly available information. We don’t claim affiliation or endorsement, and we always recommend you double-check specs and consult with a qualified sparky before making a decision. Equity Solar Brokers is not a solar installer — we’re your independent solar matchmaker. And yes, we read the fine print so you don’t have to.

 

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.