Why energy trading with your solar battery is more burnout than breakthrough
Why most of the “savings” claims don’t stack up
Every week, we hear the same thing:
“I’ll trade power at peak times and make bank.”
“Without a battery, solar is pointless.”
My home doesn't use much power during the day, so there's no way I'll save much without a battery
Spoiler alert: there's truth to each of these claims. And batteries are useful, yes.
But are they the financial slam dunk some companies pitch them to be? Not really.
First Things First: The Blackout Question
Yes, a battery means your solar can keep running when the grid drops out. Without one, your system shuts down to ensure you're not sending power down lines that may soon be under repair.
For many, backup power from solar is a priceless piece of mind. Fridges cold, Wi-Fi humming, lights on, mmmmm.
But let’s be honest: most of us aren’t buying a $15k battery just to keep Netflix running during a storm. What we really want to know is: will it save me money, pay for itself quickly, and give me a better ROI?
Solar Alone: Potentially the best low risk investment on the planet (20% ROI)
Take a 17-panel system (7.8kW), costing around $14k:
Generates ~10,500 kWh/year.
You’ll use about 35% directly = $1,500 saved at 36c per kWh (typical in 2026)
The rest gets exported to your retailer for ~18c/kWh = $1,228 in credits.
That’s $2,728 per year in your pocket, and a 5-year payback. No battery required.
What Happens With a Battery?
Adding a decent battery allows you to use more of your solar, shaving more off your bill. Sounds great, but let’s check the numbers:
17 panel solar + battery setup ~$24,000.
Annual savings ≈ $3,500 if you're lucky - because nobody uses all their solar, even with a battery
Payback = 6-7 years.
ROI of about 15%, which is still world class.
So yes, a battery saves a bit more. And while the ROI is lower ~(15% instead of 20%); it's still a great investment when you zoom out and consider the whole picture.
However - when you zoom in - you spend $10k more and save about $700 more. Give or take up to a few hundred either side, which is dependant on your energy patters and power rates.
So, lets be generous and say that a $10k battery saves you another $1000 per year.
Payback = 10 years on just the batter
ROI of about 10%, but with a ~15 year life expectancy, the battery barely pays for itself twice over.
Batteries are worth your money, because they offer backup power, and that's priceless.
But on a purely financial basis and as compared to solar only, batteries aren't yet a home-run investment.
The Energy Trading Myth
Here’s where it gets funny. Some retailers (Ecotricity, for example) pay 21c/kWh from 5–9pm. Clients often tell us:
“I’ll make sure my battery is charged by 5pm so I can export then.”
Except in 2026, the peak power rate on those peak/off peak solar plans sits around 40c/kWh, or more! So why would you sell your power for 21c? Much better to use it instead of buying it!
Selling solar for 21c during peak hours is like buying a bottle of wine for $40 and selling it for $21 — and then going thirsty.
Worse still, heavy trading cycles hammer your battery faster, and most warranties only cover one cycle a day. You’re not “winning,” you’re just burning tread.
Smarter Ways to Boost Savings
Shift your loads: run appliances when the sun’s out.
Hot water diverters: cheap tech that stores solar in water, not batteries.
Off-peak charging: some retailers let you fill your battery cheap at night and use it during the day.
These often deliver more bang for your buck than running a “battery stock market” from your garage.
So, Are Batteries Worth It?
If backup power or maximum savings is high on your list — or you want to unwind a finger to the power companies — a battery makes sense.
But if it’s just about getting your money back as quick as possible - solar alone is the best hand to play.
Should I future proof my system for a battery later?
Sometimes your best future proofing strategy is to not future proof at all.
