Solar Battery Storage UK

A battery stores the electricity your panels make while you are out, so you can use it after dark instead of buying it back from the grid. Without one, most of a UK household's generation is exported for a fraction of what it costs to import. The battery is what turns a good generation figure into a lower bill.

Yes, and it is one of the most common jobs we do. An AC-coupled battery sits alongside your existing inverter and needs no change to the panels or their wiring, so the retrofit is largely independent of who installed the original system. We check your inverter, your consumer unit and your evening load, then size the battery to what you actually use after sunset.

Lithium iron phosphate, in almost every domestic case. It runs cooler than older lithium chemistries, tolerates being cycled daily, and holds a usable share of its capacity for far longer. What separates good units is not the chemistry but the warranty terms, the usable capacity against the headline figure, and whether the system supports backup during a power cut.

Ten to fifteen years in normal domestic use. Batteries are warranted on cycles and throughput rather than years alone, so a unit cycled once a day reaches its limit sooner than one cycled three times a week. Most warranties guarantee a percentage of original capacity at the end of the term, which is the number worth comparing rather than the headline lifespan.

Size it to your evening and overnight use, not to your panel array. Look at what your house draws between sunset and sunrise on a normal day, then match that. A household using around 8 kWh after dark is served by a battery in that range. Going larger stores power you never use; going smaller sends the surplus back to the grid at export rates.

We install nationwide, with our densest coverage across London, the Thames Valley and the surrounding counties. Coverage matters more for batteries than for panels, because a battery needs commissioning, firmware updates and occasional attention over its life. Ask us directly about your postcode rather than assuming, and we will tell you plainly if you sit outside the area we serve properly.

We fit FoxESS, SigEnergy SigenStor and Tesla Powerwall, which between them cover most domestic and light commercial needs. FoxESS spans the widest range of capacities and is the most common on our installs. Sigenergy suits systems where the inverter and battery are specified together. Tesla Powerwall 3 includes its own inverter, which changes how the system is designed.

Price is driven by four things: usable capacity against the headline figure, whether the unit includes an inverter, whether backup during a power cut is supported, and how much electrical work your consumer unit needs. A retrofit onto an existing system costs less than a battery specified alongside a new array. We publish real figures at the site visit rather than a range that fits nobody.

It raises the share of your own generation that you actually use, typically from around a third to well over two thirds. Power you use yourself displaces grid electricity at the moment it is drawn, which is when the grid is most likely to be running gas. Exporting instead sends it out at a time the grid may not need it.

Yes, on most systems we fit. FoxESS and Sigenergy both scale by adding modules to an existing installation, which is why we size conservatively when a household is unsure. Tesla Powerwall expands by adding a further unit rather than a module. What limits expansion is usually the inverter capacity and the space around the existing installation, so we plan for it at the site visit.

Lithium iron phosphate dominates domestic installs, and it is what we fit. Older lithium nickel manganese cobalt units store more per kilogram but run hotter and degrade faster under daily cycling. Lead-acid still appears off-grid, where cost matters more than lifespan. For a UK home cycled daily, the chemistry question is largely settled and the warranty question is not.

Very little. Panels need nothing beyond occasional cleaning and an eye on output. Batteries update their own firmware and report through the app, so the practical maintenance is noticing when something stops reporting. We recommend a professional inspection every few years, mainly to check connections and mountings rather than the electronics. The inverter is the component most likely to need attention first.

It moves your consumption off the grid at exactly the times the grid is most expensive and most carbon-intensive. Weekday evenings are the peak on both counts. A battery charged at midday and discharged between four and eight covers that window, which is also when most households use the largest share of their daily electricity.

Usable capacity rather than the headline figure, since the two differ. The warranty terms, stated in cycles or throughput as well as years. Whether backup during a power cut is included, because it usually is not by default. Compatibility with your existing inverter if you are retrofitting. And the round-trip efficiency, which decides how much of what you store you get back.

For most households with solar, yes. Without a battery you typically use about a third of what you generate and export the rest for a fraction of the import price. A battery pushes self-consumption past two thirds. The gap between what you save on a unit you use and what you earn on a unit you export is the whole argument.

Yes, and the UK case is stronger than in sunnier countries. British generation peaks at midday while household demand peaks after dark, so the mismatch a battery solves is larger here. With the Ofgem cap at 26.11p per kWh for July to September 2026 and export worth a fraction of that, every unit moved from export to self-use is worth the difference.

Surplus generation charges the battery instead of going to the grid. When the panels stop producing, the battery discharges to cover the house until it is empty, then the grid takes over. The system decides this automatically, second by second, based on what the house is drawing. Most units also charge from cheap overnight tariffs if you have one.

Match it to your overnight use. Take a normal day, look at what the house consumes between sunset and sunrise, and size the battery to that figure. For most UK homes that is 5 to 15 kWh, sized to daily usage. Sizing above your evening load stores power you never draw; sizing below it sends the surplus out at export rates.

Between 5 and 15 kWh covers most UK households, sized to daily usage. Work it out from your own half-hourly data rather than a rule of thumb: your evening and overnight consumption is the number that matters, not your annual total and not your roof size. A house with an electric car or a heat pump sits at the top of that range or above it.

Cost tracks usable capacity, whether the unit includes its own inverter, and whether it supports backup during a power cut. A retrofit onto an existing array costs less than a battery specified with a new system, because the inverter and much of the wiring already exist. We give a real figure after seeing your consumer unit and your consumption, rather than a range wide enough to be useless.

The same four things decide it: usable capacity, whether an inverter is built in, whether backup is included, and the electrical work your board needs. Beware headline capacity, because usable capacity is lower and is what you actually get. We quote against your own evening consumption, so the number reflects the battery you need rather than the one that is easiest to sell.

Yes. An AC-coupled battery works alongside almost any existing inverter, so the retrofit rarely touches the panels or their wiring. What we check first is your consumer unit, the space around the proposed location, and your evening load. Retrofits are usually simpler than people expect, and they are the fastest way to raise self-consumption on a system already generating well.