AC-Coupled Night-Time Download: add a battery, charge it on cheap night rates
An AC-coupled battery can be added to any home. With solar, or without it. It charges overnight on a cheap night rate, and the house uses that power during the day.
Photographs: illustrative library images. Not necessarily our installs.
NICEIC registered · 118 five-star reviews · 10-year workmanship guarantee
What an AC-coupled battery is
An AC-coupled battery has its own inverter. It connects at the consumer unit, on the AC side of the house. It does not replace the solar inverter you already have.
It can charge from the grid. It can charge from solar. It can do both. Some energy is lost between charge and discharge. We size for that. We do not pretend every unit comes back out.
The house stays on the grid. If you want backup in a power cut, or to leave the grid entirely, see Off-Grid Purge Mode.
Illustrative photograph of a home battery. Not necessarily our install.
Add a battery to existing solar, or start without solar
Speak directly to the electrician who will turn up.
No solar required
The battery can go into a house that has never had panels. It charges from the grid.
Overnight charge
It fills on a cheap night rate. The stored power is there for the day. The rate is your tariff, not a promise from us.
Works with existing solar
It sits next to the inverter already on the wall. Whether the bill falls depends on the tariff, the battery, and how the house uses power. We do not quote a saving.
Cheap night rate battery charging: rates checked October 2026
Overnight rates are often in the region of 7–9p/kWh. These are supplier off-peak unit rates, not our prices.
- EDF GoElectric. From around 6.66p/kWh, 11pm to 6am. Published on EDF’s GoElectric page.
- Intelligent Octopus Go. From around 7.6p/kWh, 11:30pm to 5:30am. West Midlands fixed tariff then on sale.
- Octopus Go. From around 9.5p/kWh, 12:30am to 5:30am. West Midlands fixed tariff then on sale.
- British Gas EV Power. From around 9.5p/kWh, midnight to 5am. Published on the British Gas EV tariff page.
Rates change. Check your tariff.
These tariffs, including Octopus Go and Intelligent Octopus Go, are mainly sold to homes that charge an electric car. Where the night rate covers the whole home, the battery can charge in that window. A battery on its own does not qualify you for the tariff. Daytime rates are higher. We have not set them against the night rate, and we are not quoting a saving.
Battery storage in Birmingham: what the job involves
We look at the consumer unit, where the battery can sit, the cable run, and any solar already on the roof. For a home we fit lithium iron phosphate batteries. Location and clearances follow PAS 63100:2024. The wiring follows BS 7671 and the IET Code of Practice for Electrical Energy Storage Systems.
If the battery connects to the grid, the DNO is told. Smaller type-tested equipment is usually a G98 notification, up to 16 amps per phase. That is 3.68 kW on a normal single-phase supply. Larger equipment, or a house that already has generation, is usually a G99 application before connection. If the network caps export, a G100 export limit is fitted. We deal with the DNO.
BPEC-qualified solar installer, installs MCS certified through Greenwatt Energy. Solar and battery installs both go through that route. We are NICEIC registered for the electrical work. Nearly 30 years’ experience. £10m public and employers’ liability insurance. Our workmanship guarantee is 10 years. Equipment warranties are the manufacturer’s, and they vary.
Price: call for a fixed quote. It is set after a survey.
AC-coupled battery: quick answers
Can I add a battery to existing solar?
Yes. An AC-coupled battery sits alongside the inverter you already have. The survey checks the consumer unit, the cable run, and any generation already connected.
Can a battery be added with no solar?
Yes. An AC-coupled battery connects on the AC side of the house. It does not need panels. It can charge from the grid overnight.
Does it work with Octopus Go or Intelligent Octopus Go?
The battery can be set to charge in the cheap night window on tariffs like Octopus Go and Intelligent Octopus Go. Those tariffs are mainly sold to homes that charge an electric car. A battery on its own does not qualify you. Check the tariff terms with your supplier.
What are the overnight rates?
Checked in October 2026, published off-peak rates were: EDF GoElectric from around 6.66p/kWh (11pm–6am), Intelligent Octopus Go from around 7.6p/kWh (11:30pm–5:30am), Octopus Go from around 9.5p/kWh (12:30am–5:30am), and British Gas EV Power from around 9.5p/kWh (midnight–5am). The Octopus figures are the West Midlands rates on the fixed tariffs then on sale. Rates change. Check your tariff. These tariffs are mainly for homes that charge an electric car. We do not quote a saving.
What does it cost?
Call for a fixed quote. The price is set after a survey.
Does the network need to know?
Yes, when the battery connects to the grid. Smaller type-tested equipment is usually a G98 notification, up to 16 amps per phase. That is 3.68 kW on a normal single-phase supply. Larger equipment, or a house that already has generation, is usually a G99 application before connection. If the network caps export, a G100 limit is fitted. We deal with the DNO.
Who certifies the install?
BPEC-qualified solar installer, installs MCS certified through Greenwatt Energy. The electrical work is NICEIC registered. The workmanship guarantee is 10 years.
Where do you cover battery storage?
Birmingham and the West Midlands.