Using your home battery to earn money from your solar system sounds like something only tech enthusiasts do. But if it’s a possibility, why would you not? Your battery is always discharging and charging, and if you can use it to maximise your earnings, minimise your costs and even play its part in strategically making a little money? Great.
At Electrical Innovations, we’ve set these systems up for hundreds of customers across the Midlands. In this guide, we’ll walk through a simple, real-world approach to setting up solar, battery storage and smart tariffs so your system works hard for you.
How your solar and battery system makes and saves money
Your panels produce electricity in daylight. Your home uses some of that power straight away. Anything left over goes either into your battery (if you have one) or out to the grid via the Smart Export Guarantee (SEG).
If you have no battery, that’s okay. Follow the standard common-sense approach:
- Daytime: panels supply the house first, then export the surplus via the SEG.
- Nighttime: you pay your supplier for every kilowatt-hour you use for heat, light, etc.
However, add a home battery and sign up for time-of-use tariffs, and you open yourself up to far more benefits:
- Daytime: the battery and panels supply the house together.
- Nighttime: the battery and/or the grid (off-peak rates) power your home.
- Peak periods: the battery supplies the house, so you avoid higher unit rates.
- Off-peak periods (including night): the battery charges from cheap grid electricity.
- Surplus daytime energy: once the battery is full, export all surplus to the grid through the SEG tariff.
Real life methods to save and make money
The figures below are accurate at the time of writing (November 2025), but naturally subject to change.
And here is where you can start actually making some money. Some providers offer excellent time-of-use tariffs. At the time of writing, Octopus Energy has some fantastic offerings, including the Intelligent Octopus Go, designed for overnight EV charging.
In this example, overnight import tariffs (for the electricity you use) are much lower. Right now, it’s 7p per kWh. Exports (electricity you send back to the grid) through a separate tariff, like Outgoing Octopus, get you a much higher rate. Right now, it’s 15p per kWh.
You can get even get a premium rate at certain times with some policies, like Octopus Flux or Intelligent Octopus Flux, where you could get up to 30p per kWh between 4pm and 7pm.
Now, those numbers can shift over time, but the opportunity is clear for all to see: buy when the price is low, and use or export when the price is high.
The end result is a loop:
- Charge the battery from the grid overnight during the cheap window.
- Let your panels and battery run the house through the day.
- Export surplus solar, and potentially even excess charge in your battery, at the higher rate.
- Repeat, with minimal day-to-day effort once set up.
Setting smart charging and export times
To get that loop up and running, the clever part lies in how you set up your battery schedule and tariff.
On the systems we typically install, your installer will use the cloud platform and app to set a cheap-rate charging window overnight (with the Octopus tariffs we looked at earlier, that would be 11.30pm to 5.30 am, again as of the time of writing) and a daytime export window when the battery pushes power back to the grid.
Here’s a simplified version of how that works over a typical spring or summer day.
Overnight
- The battery charges from the grid during the cheap overnight window.
- The app shows a rising ‘battery charge’ line as it fills.
- Once full, the house draws very little from the grid until morning.
Daytime
- As the sun comes up, the panels start to generate.
- The house uses some of that power, but since you’re likely at work, it’s not much; any extra either tops the battery or flows out to the grid via the SEG.
- On brighter days, the export graph often mirrors the solar generation graph – that is, most of the surplus goes out as paid export through the SEG.
Evening and export window
- In the late afternoon and early evening, your household electrical demands (cooking, showers, heating, appliances, EV charging, etc.) usually rise.
- So, at this point, the battery feeds the house.
- On some tariffs, you get a premium rate for exporting electricity during this period, around 4pm to 7pm.
- Otherwise, you can continue exporting any surplus electricity, or electricity you’re unlikely to need in the evening, from the battery and solar panels.
And then the cycle repeats again.
Does this battery + tariff approach still work in winter?
The key point here is that, once you’ve had a professional installer set all this up, your home essentially runs on autopilot. You’ll want to check the smart meter and the app every now and then. Still, you’ll probably only need to make a few detailed tweaks a couple of times per year (for example, when switching between winter and summer settings).
And that’s an important point to note. This approach still works in winter, but because solar generation drops sharply, especially from November to February, the battery relies even more on cheap-rate overnight charging. However, it can still…
- fill during the low-cost window
- power the house in the morning and afternoon
- export during premium periods (e.g., 4pm to 7pm on Flux-type tariffs)
… but you don’t get as many benefits from the solar panels in these months.
How the inverter affects how much money you can make
To maximise the effectiveness of this system, it’s really important to get the right inverter. The inverter size limits throughput, which affects how much money the system earns.
For example, a 3kW inverter rating means the maximum charging rate of the battery is 3kW, so it can charge 3kWh per hour. The same is true for discharging or exporting, a 3 kW inverter can discharge at 3 kW, or 3 kWh per hour.
So, if you’re trying to make the most of a premium export rate (such as the 4pm to 7pm window in the current Flux tariff), the maximum amount of energy you can export is 3kWh per hour. In this three-hour window example, that means 9kWh total.
If, for instance, you have a 20kWh battery, you’ll still have plenty of electrical energy left over when the export window closes. And you could still export more if you want to. It’ll just be at a lower rate.
This can mean making a significant amount more through your exports, especially if you want to maximise those peak export rates. It also means faster charging during those cheap-rate periods.
Now, a big inverter isn’t for everybody, but it’s certainly worth finding out more. All this is why, when we quote systems for homeowners in the Midlands, we don’t just talk about the size of the battery but also – just as importantly – how fast the inverter transfers power.
Making EV charging work with your battery
If you have an EV, that introduces yet another aspect. Smart tariffs might start charging your EV during the day at a lower rate. And because the charger sits ‘behind’ the same meter as the battery, the battery begins to feed the car, too.
That leads to a few occasional quirks. The car is receiving cheap grid energy while the battery is discharging, draining stored energy that might have earned more as export later. There are two main approaches to improve this:
Leave it as it is
- Accept the odd daytime charge at cheap rates.
- Treat any slight battery discharge into the car as part of normal charging behaviour.
Have your installer wire the EV charger outside the battery’s ‘view’
- The charger still uses solar export and cheap grid energy.
- The battery no longer tries to feed it during automatic charging slots.
We’d be happy to walk you through both approaches, but the right option for you once again comes down to the following. What’s more valuable to you? Set-and-forget simplicity or fine-tuning every last penny?
Bringing it all together with Electrical Innovations
If you like the idea of your solar and battery working together in the background to significantly lower your bills and increase your export income, we’re here to help. At Electrical Innovations, we design and install systems just like this in homes across Derby and the wider Midlands region.
We’re experienced in doing this, and we love chatting with homeowners to help you figure out the best approach to meet your needs.
Get in touch for a friendly chat. We’ll walk you through the options, explain the tariffs in plain language and design a solar and battery setup that earns its keep, all while you get on with your everyday life.
