If you already have solar panels, or you are planning a new system, one question comes up more than any other: what does solar battery storage actually cost in London, UK? It is a fair question, because battery prices vary more than almost any other part of a renewable energy system, and the wrong size battery can mean paying for capacity you never use.
At Proton Energy Solutions, we install solar battery storage across Orpington, Bromley, Croydon and the wider South London area, usually alongside solar panels or as part of a combined system with a heat pump. This guide breaks down real 2026 pricing, what changes the cost, and how to choose a battery that actually earns its keep.
How Much Does Solar Battery Storage Cost in London
Solar battery storage in the London typically costs between £3,000 and £10,000 fully installed, depending on capacity, brand and whether it is fitted alongside new solar panels or retrofitted to an existing system. A small 5kWh battery suited to a modest household sits toward the lower end of that range. A larger 10kWh to 15kWh system, better suited to homes with a heat pump or an EV, sits toward the top.
If you are installing solar panels and a battery together, the combined project cost is usually higher overall, often in the £8,000 to £14,000 range, because you are covering panels, inverter, mounting, battery and labour in one job. Retrofitting a battery to existing solar panels can sometimes add extra cost if your current inverter is not battery compatible.
What Affects Solar Battery Storage Prices
A handful of factors explain almost all of the price difference between quotes.
Battery capacity is the biggest driver. The more kilowatt hours a battery can store, the higher the price, though larger batteries usually offer better value per kWh than small ones.
Battery chemistry matters too. Most modern home batteries use lithium ion or lithium iron phosphate cells, prized for safety, longer cycle life and better performance in cooler UK conditions. These sit at a higher price point than older lead acid batteries, but last considerably longer.
Inverter compatibility is often overlooked. If your existing solar inverter cannot handle battery storage, you may need a hybrid inverter or an AC coupled battery, which adds to the cost of the project.
Household energy use plays a role in sizing. A home with a heat pump or an EV on charge overnight will draw down a battery much faster than a household with neither, so correct sizing avoids paying for a battery that cannot cover your evening load, or one that is oversized for your needs.
Solar Battery Storage Cost by Size
| Battery size | Typical installed cost |
| 5kWh | £3,000 to £4,500 |
| 10kWh | £4,500 to £7,500 |
| 15kWh+ | £7,500 to £10,000+ |
These figures are guide prices rather than fixed quotes. Your actual cost depends on the property, existing electrical setup and chosen brand. A proper site survey is the only reliable way to get an accurate number, which is why we offer a free design and quote as part of every solar panel installation project.
Solar Battery Storage vs Solar Panels Only
Solar panels without a battery send a large share of what they generate straight back to the grid, often for a fraction of what you would pay to buy that electricity back later in the evening. Adding battery storage means you use more of your own generation, rather than exporting it cheaply and importing it again at a higher rate.
This is particularly relevant for households on time of use tariffs, where electricity can be charged into the battery overnight at a low rate and used the next day. For homes with a heat pump, the case for a battery is even stronger, since heating demand tends to peak in the evening and overnight, exactly when solar panels are not generating.
Current UK VAT relief on qualifying residential battery installations also makes now a sensible time to add storage, whether alongside new solar panels or as part of a wider combined energy system you already own.
Is Solar Battery Storage Worth It in London
For most homes in the Bromley, Orpington and Croydon area, battery storage makes sense when at least two of the following apply: you already have solar panels generating more than you use during the day, you are on or considering a time of use tariff, you run a heat pump or charge an EV overnight, or you plan to stay in the property for eight years or more.
Solar Battery Storage _ Efficient Energy Solutions
If none of these apply, solar panels alone may still deliver strong savings without the added cost of a battery. This applies to commercial premises too, where our commercial solar systems follow the same sizing logic. This is exactly the kind of decision worth talking through with an installer before committing, rather than guessing at the right size from a generic table.
How to Get the Best Solar Battery Storage Quote
The most reliable way to get an accurate price is a proper site survey rather than an online estimate. At Proton Energy Solutions, we design combined systems that bring together solar panels, battery storage, heat pumps and air conditioning where relevant, so the battery is sized correctly for your actual household demand, not just your roof space.
We install trusted battery brands including Sigenergy and Fox ESS, and every quote includes a free design service so you know exactly what you are paying for before any work begins. You can get a free quote here.
Frequently Asked Questions
- How much does a 10kWh solar battery cost installed in the UK?
A 10kWh solar battery typically costs between £4,500 and £7,500 fully installed, depending on brand, inverter compatibility and installation complexity. - Can I add a battery to my existing solar panels?
Yes. Most solar panel systems can have battery storage retrofitted, though your installer will need to check whether your current inverter supports it or whether a hybrid inverter is needed. - Is solar battery storage worth it without solar panels?
It can be, particularly on a time of use tariff where you charge the battery from the grid overnight at a lower rate. However, the savings are usually stronger when paired with solar generation. - How long does a solar battery last?
Most lithium-based home batteries last between 10 and 15 years, with warranties typically covering a set number of charge cycles rather than years alone. - Does a heat pump change what size battery I need?
Yes. A heat pump can draw several kilowatt hours during a winter evening, so homes with a heat pump usually benefit from a larger battery than those without one.
