Store the solar power you don't use during the day, or charge on a cheaper overnight rate, and use it in the evening. We fit home battery storage with new solar panels or alongside the ones you already have unconfirmed.
Getting solar panels too?
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Solar panels make most of their power in the middle of the day, when many homes use the least. Without a battery, the spare goes to the grid for a small export payment, and you buy power back in the evening at the full rate. Solar battery storage keeps that spare power for later.
A home battery can also charge from the grid overnight on a cheaper time-of-use tariff, then run your home through the expensive evening hours. With the right equipment, it can keep some or all of your home running in a power cut.
A battery tends to suit you if:
It may not pay its way if you're home all day using your solar as it's made, or your system is small and rarely has power to spare. If that's you, we'll say so.
We design the panels, a hybrid inverter and the battery as one system, sized to your roof and your usage from the start. Your quote covers the panels and the battery together.
Most existing systems can take a battery unconfirmed. Depending on your inverter, we fit a battery that works alongside it or replace it with a hybrid inverter that runs both. If you're on the Feed-in Tariff, we set the battery up so your payments carry on as before unconfirmed. When we call, we'll ask for a photo of your inverter and a recent bill, then tell you what's possible.
A battery can work without panels, charging overnight on a cheap tariff and running your home at peak times. Ask us whether it makes sense for your home and tariff.
We're not tied to one manufacturer. We recommend the battery that suits your home, your inverter and your budget, then install it, set it up and register it.
| Battery | What it's like | Where we've fitted it |
|---|---|---|
| Tesla Powerwall 3 | An 11.04 kW integrated inverter with 13.5 kWh of battery storage in an all-in-one unit; more units can be added; whole-home backup with Tesla's Backup Gateway unconfirmed | Trevor Little's home in Derby; a home with a Powerwall 3, an expansion unit and Backup Gateway unconfirmed |
| Fox ESS battery | A top pick among our installation team, offering excellent value and a user-friendly customer monitoring platform. | Dave Samworth's home in Grantham (10.36 kWh); a home in Burton upon Trent (EP12 battery) unconfirmed |
| EcoFlow PowerOcean | Modular batteries with an app and a home display | A home in Hilton, near Derby (two 5 kWh batteries) unconfirmed |
| Enphase IQ Battery 5P | 5kWh modular storage with AC-coupling for easy retrofitting, and micro-inverters that suit chimneys or complex roofs. | Ask us for a recent example |
We also fit batteries from Sungrow and SolaX.
Your solar battery cost depends on the battery's size and make, and on whether it goes in with new panels or alongside existing ones. As a guide, our solar systems with a battery start from about £7,000 for 3.68 kW of panels and about £8,100 for 7 kW unconfirmed. For a battery added to panels you already have, the price depends on your current inverter; we'll give you a fixed written quote after the survey.
0% VAT. Batteries fitted to homes, with or without solar, are zero-rated for VAT until 31 March 2027 unconfirmed.
Spread the cost. Finance is available through our finance partners, Hometree and Phoenix. All finance subject to status and credit checks.
No pressure. A 14-day cooling-off period on home installations, and a price match promise (terms apply).
As battery storage installers, we handle every step, from your first call to setting up your tariff.
We talk through your home and usage. If you already have panels, we ask for a photo of your inverter and a recent bill.
We check where the battery can go, your consumer unit and any existing system. A garage wall or an outside wall usually works; current guidance keeps batteries out of lofts, bedrooms and escape routes unconfirmed.
A battery adds to what your system can export, so we tell your network operator (DNO), or get their approval first for bigger systems, as the rules require (G98 or G99).
A battery on its own usually takes a day unconfirmed; with new panels, 1-2 days.
We set up the app and a charging schedule around your tariff, show you how it all works and send your certificates.
A battery does most for you on a tariff with cheaper hours, and we'll talk you through the options when we set it up. Questions about Octopus accounts or tariffs? Octopus can help at hello@octopus.energy.
Eight 480 W LONGi panels, a 3.68 kW inverter and two 5 kWh batteries. Because the inverter is 3.68 kW, the system came under G98: we installed straight after the survey and told the DNO afterwards unconfirmed.
A 5 kW Fox ESS hybrid inverter with an EP12 battery and eight 480 W LONGi all-black panels, powering the house and the car charger. In one month the household's bill was £20, and they earned £30 back in export payments unconfirmed.
Trevor Little's 16-panel GSE in-roof system and Tesla Powerwall 3, fitted alongside a new roof.
"…what impressed me most was how proactive the Mercia team were. They installed the batteries first so I could benefit from part of the system straight away, and then returned promptly to complete the panel installation once the scaffolding was sorted."
"Brandon walked us through the process calmly ( and patiently ) answering question after question. He never pushed us into purchasing anything we didn’t require…"
We fit home batteries across Derbyshire, Staffordshire, Nottinghamshire, Leicestershire and Birmingham: see all the areas we cover, or solar panels and batteries in Derby.
For many homes, yes, but not all. A battery earns its keep by moving free solar or cheap overnight power into the evening, so it pays best if you use most of your electricity after dark, drive an EV or use a time-of-use tariff. If you're home all day using your solar as it's made, it may not.
The homes we fit usually have between 5 and 20 kWh of storage. The right size depends on how much you use in the evening and overnight, how big your solar system is and your tariff. We size it from your bills and your usage, not from a standard package.
Yes. A home battery can work without solar panels unconfirmed: does Mercia fit batteries without solar?: it charges overnight on a cheap tariff and runs your home at peak times. It suits homes that use most of their electricity in the evening or are on a time-of-use tariff. Ask us whether it makes sense for your home and tariff.
Only if the system is designed for it. Most batteries switch off with the grid for safety unconfirmed. Systems with backup, such as a Tesla Powerwall 3 with its Backup Gateway, can keep some or all of your home running unconfirmed. Tell us if backup matters to you and we'll design for it.
Usually on a garage wall or an outside wall, close to the inverter and the consumer unit. Current guidance keeps home batteries out of lofts, bedrooms and escape routes unconfirmed. We agree the spot with you at the survey, so it's safe, tidy and easy to reach.
Yes. Most batteries can charge from the grid at off-peak times and run your home at peak times, and some tariffs pay more for power you export at set times. We set up the schedule around your tariff. Questions about Octopus accounts or tariffs? Octopus can help at hello@octopus.energy.
The one that fits how you use electricity. We look at your bills, your solar panels if you have them, your inverter and where the battery can go, then recommend one from the makers we fit: Tesla Powerwall 3, Fox ESS, EcoFlow PowerOcean, Enphase, Sungrow or SolaX. We're not tied to one manufacturer.
It depends on the model and how hard the battery is worked. Each manufacturer gives a warranty in years or charge cycles. We show you the warranty for the exact battery in your quote, and we register it after installation, so the cover is in place from day one.
Ask for a battery quote and we'll call you back to talk it through. If a battery won't pay its way in your home, we'll say so.
Getting solar panels too?
We talk through your home, your usage and your tariff.
We check where the battery will go, your electrics and any existing system, then send a fixed written quote.
Installation, grid paperwork, set-up around your tariff, and support.
