Battery Backup Power Sheffield
Home Battery Backup Installation
Keep essential appliances running during a power cut with home battery backup. At Sheffield Renewables, we install systems ranging from EPS emergency backup to whole-home protection across Sheffield and South Yorkshire. Fixed-price quotes available.
What Actually Happens During a Power Cut?
Most homeowners assume that if they have solar panels and a battery, their home will continue running during a power cut. In most UK installations, that is not the case.
Under UK G98 and G99 grid connection standards, grid-connected solar and battery systems must automatically disconnect from the grid during a power outage unless a properly configured backup or EPS (Emergency Power Supply) system has been installed. This anti-islanding protection is designed to protect engineers working on the electricity network.
- Keep essential appliances running during a power cut
- Choose from EPS, partial or whole-home backup
- Typical essential backup runtime of 10-24 hours depending on usage
- Automatic switchover available on compatible systems
- Solar-compatible systems can recharge during daylight
- Suitable for new or existing solar installations
Choose Your Level of Backup Protection
The level you choose determines what runs during a power cut, the hardware required and the overall cost. At Sheffield Renewables, we recommend planning backup requirements before installation so the system can be wired correctly from the start.
- LEVEL 1
EPS Emergency Socket
A single dedicated socket is wired from the inverter’s EPS output. During a power cut, this socket continues supplying power from the battery. Essential devices such as a phone charger, laptop, bedside lamp or internet router can be plugged directly into it.
- Lowest-cost and simplest backup option
- Suitable for occasional short outages
- No second consumer unit normally required
- Switchover typically under 20ms on compatible systems
- Suitable for: router, phone charging, laptop, one lamp
- LEVEL 2
Partial Circuit Backup
A second dedicated consumer unit (fuse board) is connected to the inverter’s EPS output. Selected circuits from the main consumer unit are transferred onto the backup board, typically including lighting, refrigeration, internet equipment and selected sockets.
- Powers multiple circuits simultaneously
- Lights, fridge, Wi-Fi and selected sockets continue operating
- More useful for extended outages
- Requires installation of a second consumer unit
- Switchover within 20ms on most inverters
- LEVEL 3
Whole-Home Backup
A backup gateway or automatic transfer switch is installed between the grid supply and the main consumer unit. During a power cut, the system isolates the property from the grid and automatically switches the home onto battery power.
- Every circuit and socket continues to work
- No manual action needed during an outage
- Tesla Powerwall 3: switchover under 1 second, 11kW output
- Fox ESS EPS-BOX-SP: seamless switchover, no flicker
- Requires 13.5kWh+ battery with 10kW+ continuous output for heavy loads
Battery Sizing for Backup Power
Battery capacity requirements for backup depend on what you want to run and for how long. These guidelines help set realistic expectations before the site survey.
| Backup scenario | Min. battery capacity | Min. output | Typical cost range | What it covers |
|---|---|---|---|---|
| Essential sockets only (EPS) | 5kWh | 2kW | £3,500-£5,000 | Phone charging, Wi-Fi router and one lamp. Single EPS socket. Basic reassurance only. |
| Partial circuit backup (overnight) | 5-10kWh | 3-5kW | £4,500-£7,000 | Lighting circuits, fridge/freezer, Wi-Fi and sockets. Suitable for an overnight outage under normal household use. |
| Partial backup + gas boiler continuity | 7-10kWh | 3-5kW | £5,000-£8,000 | Essential circuits plus gas boiler pump and controls. Heating continues on gas during a power cut. |
| Whole-home backup (standard loads) | 13.5kWh | 10kW+ | £8,000-£12,000 | All circuits operate normally. Electric showers and cookers not recommended for sustained use. |
| Whole-home including heat pump | 20kWh+ | 12kW+ | £12,000+ | Full-home backup including ASHP operation. Usually requires multiple battery modules or large-capacity systems. |
Costs typically include the battery, inverter and backup wiring, but exclude scaffolding or additional consumer unit work. 0% VAT may apply where eligible. Final sizing depends on your household loads and backup requirements.
Want Reliable Power During a Power Cut?
Book a free assessment and we will recommend the right backup setup for your home, explain what it can run and provide a fixed-price quote.
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If You Already Have Solar, Here's How Backup Works
Solar panels and battery storage are often marketed with backup capability implied. In reality, most standard UK solar and battery systems shut down during a power cut unless a properly configured backup or EPS system has been installed.
UK G98 and G99 grid connection rules require grid-connected systems to disconnect from the grid during an outage for safety reasons.
With a compatible backup system installed, solar generation can continue during a power cut, supplying the home and recharging the battery while the property remains safely isolated from the grid. On a sunny day, this can significantly extend backup duration beyond the battery’s standalone capacity.
Systems such as the Fox ESS EPS-BOX-SP and Tesla Powerwall 3 enable whole-home backup functionality with compatible inverter and battery systems.
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How We Install Home Battery Backup
From the initial assessment through to final commissioning, every home battery backup system is designed around your property and the level of backup protection you need. Our NAPIT-approved engineers manage the full installation, testing and handover process.
Free Assessment
Tell us what you want the battery to power during an outage, from essential circuits to whole-home backup. We assess your consumer unit, backup requirements and the best system configuration for your property.
Fixed-Price System Design
We specify the battery, inverter and any backup gateway or additional consumer unit required for the installation. Your quotation includes all equipment, installation, commissioning and certification costs.
Installation, Testing & Handover
Our NAPIT-approved engineers install and commission the system, test the backup operation under simulated power loss and guide you through the monitoring app before handover.
Common Questions About Battery Backup
Still have questions about battery retrofits? Call our Sheffield team on 0114 201 0351 for straightforward advice on your solar setup.
Can a home battery keep my house running during a power cut?
Yes, but only if backup functionality has been installed correctly. Most standard battery systems shut down during a power cut unless an EPS circuit or backup gateway has been fitted. With EPS, selected circuits continue running. With whole-home backup, most household circuits can continue operating automatically.
Why does my battery cut out when the grid goes down?
UK grid regulations require solar and battery systems to disconnect from the grid during a power cut. This protects engineers working on the network. A backup gateway or EPS circuit safely isolates your home first, allowing the battery to continue supplying power.
What is the difference between EPS and whole-home backup?
EPS (Emergency Power Supply) backs up selected sockets or circuits only, usually through a separate consumer unit. Whole-home backup uses a gateway system that automatically switches most household circuits onto battery power during an outage.
How long can a 10kWh battery run my house during a power cut?
Running essential loads only like lighting, fridge, Wi-Fi and boiler controls. A 10kWh battery may last around 18–24 hours. Heavy loads such as electric showers or heat pumps reduce this significantly.
Do I need battery backup if I have a gas boiler?
Usually yes. Most gas boilers still require electricity for pumps, controls and ignition systems. Adding the boiler circuit to the backup supply allows central heating to continue during a power cut.
Can I add backup capability to an existing battery system?
In many cases, yes. If the inverter supports EPS, partial backup can often be added later with additional wiring and consumer unit work. Retrofitting is usually more expensive than including backup from the start.
Does battery backup work with solar panels?
Yes. With a compatible backup system, solar panels can continue generating during a power cut while charging the battery and powering the home. This can extend backup duration significantly during daylight hours.
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Also From Sheffield Renewable Services
we combine solar panels and battery storage to help households use more of their own electricity and reduce reliance on the grid.
Standalone battery storage charges on cheaper overnight tariffs and powers your home during higher daytime electricity rates.
Already have solar panels? We can add compatible battery storage to existing systems using AC or DC-coupled solutions.