Last Updated on May 23, 2025

How Long Can A Solar Battery Power A House?

As more UK homeowners and landlords embrace renewable energy solutions, one question arises time and again: how long can a solar battery power a house? 

Whether you’re looking to cut energy bills, reduce your carbon footprint, or improve your energy independence, understanding the capabilities of solar batteries is crucial to making an informed decision.

How Long Can a Solar Battery Power a House?

The length of time a solar battery can power your home depends on several factors: the battery capacity (measured in kilowatt-hours, or kWh), your household’s energy consumption, and whether the battery is charged solely via solar panels or supplemented by grid electricity.

Typical Daily Household Energy Usage in the UK:

• Flat/Apartment: 4-8 kWh per day
• 2-3 Bed Semi-Detached: 8-12 kWh per day
• 4+ Bed Detached: 12-20+ kWh per day

Battery Capacity and Usage Duration Table

Battery duration depends on energy usage patterns. If only essential loads are backed up (lighting, refrigeration, and internet), a 10 kWh battery could stretch over 24-36 hours in a semi-detached property.

Factors That Affect How Long a Solar Battery Lasts During Use

• Battery Capacity (kWh) – The higher the capacity, the longer it can power your home.
• Depth of Discharge (DoD) – Not all batteries allow 100% discharge. Lithium-ion batteries often allow 80-95% DoD.
• Efficiency Rate – Includes losses during charging/discharging. Lithium-ion batteries have up to 90-95% efficiency.
• Energy Usage – Powering only essential devices significantly extends battery runtime.
• Sunlight Availability – In summer months, batteries can recharge daily. In winter, runtime might reduce due to lower solar production.

For more information on how long solar batteries last, read our in-depth guide.

Choosing the Right Battery Size for Your Home

Getting the size right is critical to performance and cost-efficiency. If you’re wondering what size solar battery you would need, it comes down to matching your average daily consumption with the battery’s usable capacity.

Those using a 100Ah or 200Ah battery might ask what size solar panel is needed to charge a 100Ah battery or a 200Ah battery, we’ve detailed that in our solar charging guides.

Real-World Example: 10kWh Battery in a 3-Bed Home

In a typical UK 3-bedroom home consuming 10 kWh daily, a fully charged 10 kWh battery can run the household for an entire day, provided it’s used efficiently. If you’re only backing up essentials, it may stretch to two days.

Learn more about solar battery costs to understand pricing by capacity and battery type.

Do Solar Batteries Work During a Power Outage?

Absolutely. With the right configuration, including a hybrid inverter and a backup circuit, your solar battery system can keep your lights and critical systems on even when the grid is down. Read our in-depth guide on how solar batteries work during a power outage for technical and setup insights.

Types of Solar Batteries to Consider

Battery chemistry impacts capacity, longevity, and cost. Most UK installations favour lithium-ion for their high DoD, longevity, and efficiency. Curious about the different types of solar batteries? We’ve broken them down with pros and cons.

Are Solar Batteries Safe?

Modern solar batteries, especially lithium-ion, are built with safety protocols including temperature control and fire suppression. Safety certifications are mandatory under UK building regulations. For a more in-depth guide, read our guide on are solar batteries safe.

Can I Add a Battery to My Existing Solar System?

Yes,  retrofitting is common in the UK. If you’re already generating solar power, integrating battery storage is a smart move to capture and store excess power. Check out our guide on can I add a battery to my existing solar system for compatibility and setup requirements.

Are Solar Batteries Worth It in the UK?

For many homeowners and landlords, the return on investment (ROI) is becoming more attractive, especially with rising electricity prices and incentives. Read our detailed guide on are solar batteries worth it.

Request Your Free Solar Battery Quote from Eco Happy

Ready to take the next step? Whether you’re looking to reduce energy bills, gain independence from the grid, or simply store more of your solar power, Eco Happy can help. We provide tailored battery storage solutions for every type of home and commercial property in the UK.

Expert advice, no obligation
Bespoke system recommendations
Trusted UK installers and certified products

Request your free solar battery quote now and find out how long your home can stay powered, the smart way.