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Solar Panels And Battery

What Size Solar Battery Do I Need?

Storing sunshine, unleashing savings! But what size solar battery do I need? 

Solar panels generate power during daylight hours, this is often when homes use the least electricity. Whilst this unused electricity can be sold back to the grid as part of an SEG, many households are benefiting more by storing this unused energy in a solar battery to use at night when your home demands more electricity. 

Adding a solar battery is a great way to use the free energy your system has created, while minimising your bills.  

With so many batteries on the market, it can be confusing to work out what size solar battery you need for your home. 

The big question is: how much battery power do you need? This depends on a few key factors, such as your household’s daily energy usage and the output of your solar panels. 

By considering these factors, you can determine the best battery size to meet your energy needs and make the most of your solar panel setup. 

No Solar Panels Yet? Don’t Worry! 

If you don’t have solar panels yet and the cost worries you, Warma UK has got your back. We specialise in designing and installing solar panel systems tailored to your home’s needs. Plus, we can help you access government grants and funding schemes to make your investment more affordable. Why wait? Click the link below to see if you qualify! 

See if you're eligible for free solar panel grant

See if you're eligible for free solar panel grant

Even if you’re not eligible for a grant, Warma UK has some of the best deals in the UK for solar panels and batteries. Give us a call to find out more. 

solar battery

What size solar battery do you need for your home? 

The size of solar battery you need for your home depends on several factors, primarily your daily energy consumption and the capacity of your solar panel system. Here are some key considerations: 

Key Considerations for Solar Battery Sizing 

  1. Daily Energy Consumption: Calculate your average daily energy usage from your electricity bills. 
  1. Solar Panel Output: Match the battery size with the energy your solar panels generate. 
  1. Depth of Discharge (DoD): Consider the usable capacity of the battery. Most batteries have a DoD of 80-90%. 
  1. Autonomy Days: Factor in the number of days you want the battery to provide power without solar input. 
  1. Future Energy Needs: Plan for potential increases in energy consumption, such as adding an electric vehicle or more appliances. 
  1. Cost Considerations: Larger batteries offer more storage but are more expensive. 

 Contact Warma UK to learn about available grants and funding schemes that could help reduce your costs significantly. Click on the link below to check whether you are eligible for a FREE solar panel grant. 

See if you're eligible for free solar panel grant

See if you're eligible for free solar panel grant

Recommended Battery Sizes 

  • For most UK households, a 5kWh battery is sufficient to store excess solar energy for use at night. 
  • Homes with higher energy consumption (above 5,000kWh per year) may require a larger battery, around 9-10kWh. 
  • The table below provides general recommendations based on solar panel capacity and average daily output: 

Solar PV Capacity (kW) 

Average Output (kWh/day) 

Recommended Battery Size (kWh) 




















The table below summarises general battery size recommendations based on household size and energy consumption: 

Household Size 

Lithium Battery Size (kWh) 

Lead-Acid Battery Size (kWh) 

1-2 people 

Less than 10.5 

Less than 20 

2-3 people 



3-4 people 



4-5 people 



5+ people 



It’s essential to work with a qualified solar installer to assess your specific needs and recommend the optimal battery size for your home’s solar system. 

How are solar battery sizes measured? 

Solar battery sizes are typically measured in kilowatt-hours (kWh), which indicates the maximum amount of energy the battery can store. 

The kWh rating represents the battery’s total energy capacity. For example: 

  • A 5 kWh battery can store up to 5 kilowatt-hours of electricity. 
  • A 10 kWh battery can store up to 10 kilowatt-hours of electricity. 

However, it’s important to note that batteries should not be discharged to 100% capacity, as this can damage them. The usable capacity, also known as the depth of discharge (DoD), is typically around 80-90% of the total capacity. 

So for a 10 kWh battery with a 90% DoD, the usable capacity would be around 9 kWh. 

The table below illustrates the relationship between total battery capacity and approximate usable capacity: 

Total Battery Capacity 

Usable Capacity (Approx) 

5 kWh 

4 kWh 

7 kWh 

5.6 kWh 

10 kWh 

8 kWh 

12 kWh 

9.6 kWh 

15 kWh 

12 kWh 

Higher kWh ratings indicate a larger energy storage capacity, but also come with a higher price tag. Choosing the right size depends on your household’s energy consumption needs and the capacity of your solar panel system. 

Why is choosing the right solar battery size important? 

Choosing the right solar battery size is key for getting the most out of your solar energy system. Going for the biggest battery or more individual batteries might seem like a good idea, but it can lead to unnecessary costs and wasted space. On the other hand, a battery that’s too small won’t meet your energy needs. 

The goal is to find the perfect balance—a battery size that matches your energy use and your solar panel’s output. A properly sized battery lets you store excess energy generated during the day and use it when needed. 

This not only maximises your solar investment but also boosts your energy independence. A well-sized battery allows you to go off-grid for longer periods without relying on the utility grid saving you money and reducing your environmental impact.  

Finding the ideal battery size involves a careful look at your energy needs, solar panel capacity, and how long you want to rely on the battery. While this might seem daunting at first, taking the time to get it right will pay off with a reliable, efficient, and cost-effective solar energy solution. 

Why Choose Warma UK? 

Investing in a solar battery system is a smart move, but to get the most value, you need to partner with experts. Warma UK specialises in designing tailored solar panel and battery storage solutions that fit your home’s unique needs. 

With quality products, competitive pricing and famously fantastic customer service, Warma UK makes transitioning to solar energy straightforward and affordable. We can also help you tap into government grants and funding schemes, potentially covering significant costs if you qualify. 

Contact Warma UK at 01874 442 861 to explore how easy and affordable achieving energy independence can be. With their expertise, you’ll harness the power of the sun and enjoy sustainable energy for years to come. 

See if you're eligible for free solar panel grant

See if you're eligible for free solar panel grant

Athira Harish