Last Updated on May 22, 2025

How Do Solar Batteries Work?

If you’re generating solar energy or planning to install a solar PV system on your property, it’s only natural to ask: how do solar batteries work? Solar battery storage is fast becoming essential for UK homeowners, landlords, and commercial property owners who want to reduce their reliance on the grid, save money, and maximise their return on renewable energy.

In this in-depth guide, we’ll explain how solar batteries store and discharge electricity, the types of solar batteries available, and how they work with solar panels. You’ll also find key considerations around costs, lifespan, and installation. 

If you’re considering investing in solar battery storage, this guide will help you make an informed decision.

How Do Solar Batteries Work Step by Step

To understand how solar batteries work, let’s break the process down:

1. Solar Panels Generate DC Electricity
   Your solar panels convert sunlight into direct current (DC) electricity throughout the day.
   
2. Inverter Converts DC to AC
   This DC power is then sent to an inverter (or hybrid inverter), which converts it into alternating current (AC) that powers your home or building.
   
3. Power is Used or Stored
   
   • If your property is consuming electricity, it uses the solar energy first.
     
   • Any surplus energy is stored in your solar battery system instead of being exported to the grid.
     
4. Battery Stores Energy as Chemical Potential
   The battery stores energy through electrochemical reactions (most commonly lithium-ion or lead-acid reactions). The energy is held in reserve until it’s needed.
   
5. Battery Discharges When Needed
   When your solar panels aren’t generating power (like at night or on cloudy days), your system will draw from the battery first, reducing your dependence on the grid.
   

Solar Batteries and Energy Independence in the UK

With rising energy bills and increasing uncertainty around grid reliability, UK homeowners and landlords are looking for smarter solutions. A well-sized solar battery system allows you to:

• Increase your solar self-consumption
  
• Reduce electricity bills by avoiding peak-time tariffs
  
• Minimise export losses from unused solar energy
  
• Maintain power during blackouts with the right setup – solar batteries can supply energy during outages, depending on your system configuration

In areas with unstable power or for landlords managing multiple units, solar battery storage can provide peace of mind and long-term cost savings.

Types of Solar Batteries Used in the UK

Different battery chemistries offer different benefits. Here are the most common:

• Lithium-ion Batteries – Most popular due to high efficiency, long lifespan, and compact size.
  
• Lead-acid Batteries – A budget-friendly option with shorter lifespan and lower depth of discharge.
  
• Saltwater Batteries – Environmentally friendly but less common.
  
• Flow Batteries – Ideal for large-scale commercial systems.

For a full breakdown, read our guide on the different types of solar batteries.

How Solar Batteries Integrate with Your System

A solar battery isn’t a standalone product, it’s a key part of your wider home energy system. When integrated properly, it works in harmony with your solar panels, inverter, and your property’s electricity usage. 

Here’s a breakdown of the core components involved and how they contribute to the system:

• Battery Inverter (or Hybrid Inverter)
  This is the brain of your solar battery setup. It converts the DC electricity stored in your battery into AC electricity for use in your home. A hybrid inverter can manage both your solar panels and battery simultaneously, simplifying the system and improving efficiency.
  
• Battery Management System (BMS)
  The BMS ensures your battery operates safely and efficiently. It monitors the battery’s health, regulates charging and discharging, prevents overcharging or overheating, and extends the lifespan of your solar battery.
  
• Monitoring Interface
  Most modern solar battery systems include a user-friendly app or online dashboard. This allows you to track how much solar energy you’re generating, how much you’re storing, and how much you’re drawing from the grid—empowering you to make smarter energy decisions and reduce costs.
  
• Battery Enclosure (for outdoor systems)
  If your battery is installed outside, it will be housed in a weatherproof, secure enclosure. This protects the system from UK weather conditions and ensures long-term reliability.

When installed by a professional, these components work seamlessly to help you capture, store, and use more of your own renewable energy, bringing you one step closer to energy independence.

Grid-Tied vs Off-Grid

• Grid-tied systems let you draw power from the grid when needed and export surplus solar energy (often under the Smart Export Guarantee).
  
• Off-grid systems rely solely on solar generation and battery storage. These require larger capacity and more complex design.

Factors to Consider Before Installing a Solar Battery

1. Battery Capacity and Size

Choosing the right solar battery capacity is essential for maximising your energy independence and cost savings. The size you need will depend on how much electricity your household consumes and how much excess energy your solar panels generate.

If you’re unsure where to start, understanding what size solar battery you need can help you match your energy usage to the correct storage capacity, whether you’re trying to power just evening usage or store enough for several days.

It’s also important to consider how your solar panel system supports battery charging. For example, the size of solar panel needed to charge a 100Ah battery will be different from what’s required for a 200Ah battery, depending on your battery type, charge rate, and daily sunlight hours.

Working with a professional installer like Eco Happy will help ensure your system is properly sized to meet your needs efficiently.

2. Battery Lifespan

Modern lithium-ion batteries can last 10–15 years, depending on usage, depth of discharge (DoD), and ambient temperature. Read our guide on how long solar batteries last to get a better understanding. 

3. Costs and Return on Investment

The cost of solar batteries vary based on capacity and brand. But long-term savings can outweigh initial investment.

4. Solar Battery Safety

Modern solar batteries are designed with multiple built-in safety features, including thermal management, surge protection, and fire-resistant enclosures. Most systems also come with a Battery Management System (BMS), which monitors temperature, charge levels, and performance in real-time to prevent issues before they arise.

When properly installed and maintained, solar batteries are extremely safe for use in UK homes and commercial properties. If safety is a concern, it’s worth checking out our guide on are solar batteries safe to understand the technologies and regulations that protect your investment and your property.

5. Installation

Installation plays a critical role in the performance, lifespan, and safety of your solar battery system. A professional installer will assess your property’s layout, electricity usage, and existing solar setup to determine the best location and configuration for your battery, whether that’s indoors or in a weatherproof outdoor enclosure.

Certified installers ensure that your battery is compatible with your solar inverter, adheres to UK regulations, and is positioned to maximise efficiency while allowing easy access for maintenance. 

They’ll also handle system commissioning and integrate your battery into a smart monitoring platform so you can track performance from day one.

Proper installation not only protects your equipment but ensures you get the full return on your solar investment.

Are Solar Batteries Worth the Investment for UK Homes?

Yes, solar batteries are worth it if your property generates a decent amount of solar energy and you want to reduce your grid reliance, a solar battery can absolutely pay off. Combine it with the Smart Export Guarantee (SEG) and Time-of-Use tariffs, and your return can grow even faster.

Commercial landlords can also benefit through reduced energy costs for communal areas and added value to the building’s EPC.

Ready to Maximise Your Solar Investment?

Eco Happy makes it easy to take control of your energy. Our expert team will assess your property, energy usage, and solar generation to recommend the ideal solar battery system for your home or building.

Future-proof your energy supply
Slash your electricity bills
Reduce your carbon footprint
Installed by certified professionals

Whether you’re upgrading your current solar setup or starting from scratch, Eco Happy is here to help.

Request your free solar battery quote today!