Solar Battery Cost Calculator: Price, Size and Payback
Answer a few questions about your home and your electricity use. We show the fitted price of the battery size you pick, what it saves and the payback years, with or without solar panels.
Your battery cost, savings and payback
Updates as you answerExample: 9 panels of 475 W, a 4.275 kWp system. Your answers change the saving and the payback. This calculator does not size the panels for your roof.
The battery takes about 69.2 years to pay back, which is longer than the warranty length battery makers give.
Cheap-rate charging is not included, because no day and night rates were given. The saving, the payback and the verdict rest on charging the battery from your solar panels only.
We are not offering a survey for this result. See what would change the answer, then run it again. Run it again
VAT on home solar panels and batteries is 0% until 31 March 2027. From 1 April 2027 it is 5%. Our estimate with 5% VAT would then be £9,300.
The link holds your answers only. Your postcode and any quoted price are never put in it.
- DESNZ median for this size band, per kWh on the label (the price never falls below the top of the band beneath)
- £890
- Size on the label (nominal capacity), which the price is worked on
- 10 kWh
- Usable capacity
- 9 kWh
- Yearly use (the Ofgem typical value)
- 2,500 kWh
- Example solar panels priced with it
- 9 panels, 4.275 kWp
- Yearly generation
- 4,138 kWh
- Used at home without the battery
- 21%
- Used at home with the battery
- 48%
- A typical home in our data uses with the battery
- 50%
- Solar stored, then used
- 1,235 kWh in, 1,099 kWh out
- Export lost
- 1,235 kWh
- Saving from stored solar
- £289.25
- Export income lost
- £160.55
- Saving from cheap-rate charging
- Not included: no rates given
- VAT clock: price from 1 April 2027, with 5% VAT
- £9,300
- Rate for electricity you use
- 26.32p per kWh
- Rate for electricity you export
- 13p per kWh
| Line | Panels alone | Panels plus battery |
|---|---|---|
| Installed cost | £8,400 | £17,300 |
| Used at home | 21% | 48% |
| A typical home in our data uses | 23% | 50% |
| Yearly saving | £231.62 | £520.87 |
| Export income | £423.54 | £262.99 |
| Payback | 12.8 years | 22.1 years |
| Verdict for the whole system | Borderline | Poor fit |
| 25-year net | £6,232.92 | £364.57 |
Battery price basis: the DESNZ median of £890 per kWh of nominal capacity for this size band, 1 April 2025 to 31 March 2026. Nominal capacity is the size on the label, so the price is worked on the 10 kWh you picked. The saving is worked on the usable capacity, 9 kWh.
Used at home basis: a cautious figure. Three in four of the homes like yours in our data used at least this share of their solar electricity. The saving, the export income, the payback and the verdict are worked from it.
Yearly generation basis: a stand-in figure of 968 kWh per kWp for a south roof at 35 degrees, because no postcode area in our table is set. Type your full postcode and the figure for your area is used.
Installed cost basis: the mean cost per kWp of panels fitted (total installed capacity), from DESNZ Solar PV cost data, domestic retrofit installations, 1 April 2025 to 31 March 2026.
Rates basis: the unit rate is the Ofgem price cap for October to December 2026. The export rate is our calculation from Ofgem figures.
The method and the sources are set out under the result.
Solar generation data: PVGIS © European Communities, 2001-2026.
How we worked this out
- The size you pick is the size on the label (nominal capacity)
- Price = kWh on the label x median price per kWh for its size band, never below the largest battery of the band beneath
- Usable capacity = kWh on the label x a usable share, the MCS MGD 003 default. The saving is worked on the usable capacity
- If you type a price you were quoted, the payback and the verdict use that price as typed; the saving does not change
- Stored solar = our self-use model for your home, with the battery minus without it
- Saving from stored solar = kWh delivered x the rate you pay
- Export income lost = kWh charged x export rate
- Saving from cheap-rate charging = kWh moved x day rate - kWh bought x night rate, only when you type both rates
- Payback = price / yearly saving against your present bill
With the two rate boxes empty, cheap-rate charging is not included and the saving is stored solar minus export income lost. With both rates typed, the saving is measured against your bill on your present single rate, so the cost of moving to a two-rate tariff is taken off. The verdict compares the payback with one fixed warranty length of 10 years, our rule: the shortest the battery makers state. The full method is on our methodology page, and every dataset and its date is on our sources page. This is an estimate, not a quote or advice.
How Much Does a Solar Battery Cost in the UK?
A 10 kWh solar battery costs about £8,900 fitted in the UK, based on the DESNZ median of £890 per kWh for MCS-certified battery installs in April 2025 to March 2026. Smaller batteries cost more per kWh and larger ones less.
That battery price covers the battery and its fitting, not solar panels. The figures are medians, and your own roof and wiring change the result. To price panels and a battery together, use the main calculator, and the package price is set out under solar panels and battery cost. The table below gives the battery cost from the calculator for the five sizes it offers.
| Size on the label | Usable capacity (MCS MGD 003 default share) | DESNZ size band | Median price per kWh of nominal capacity | Price from the calculator |
|---|---|---|---|---|
| 5 kWh | 4.5 kWh | Under 6 kWh nominal | £1,300 per kWh | £6,500 |
| 10 kWh | 9 kWh | 6 to under 11 kWh nominal | £890 per kWh | £8,900 |
| 13.5 kWh | 12.2 kWh | 11 kWh nominal or more | Not used: band edge rule (see note) | £9,800 |
| 15 kWh | 13.5 kWh | 11 kWh nominal or more | Not used: band edge rule (see note) | £9,800 |
| 20 kWh | 18 kWh | 11 kWh nominal or more | £630 per kWh | £12,600 |
The cheapest home battery is not always the lowest cost per kWh: the DESNZ median per kWh falls as the size band rises. Compare quotes on the price per usable kWh as well as on the total.
Solar Battery Price per kWh
The solar battery price per kWh at the DESNZ medians is £1,300 under 6 kWh, £890 from 6 to under 11 kWh and £630 at 11 kWh or more (April 2025 to March 2026). DESNZ labels the series "official statistics in development", and its data comes from the MCS installation database.
The DESNZ median price per kWh falls as the size band rises. Each band has its own median, so at the plain band figures a battery just above a band edge would price below a smaller battery just under it. That is an effect of the bands, so the calculator applies one rule of its own: a battery is never priced below the largest battery of the band beneath it. The bands are read on nominal capacity, which is the size on the label. We work the usable capacity as the label size times a usable share of 90%, the MCS MGD 003 default where a datasheet gives none.
Battery Cost With New Panels, Added Later or Without Solar
Fitting a battery with new panels and one hybrid inverter can cost less than adding an AC-coupled battery later (Solar Power Portal). The table below compares the three ways to buy a battery, and each one is a route in the calculator.
| Route | What gets fitted | Where the saving comes from | What to check |
|---|---|---|---|
| With new panels | Panels and a battery; one hybrid inverter can run both | Solar electricity stored in the day and used in the evening | The payback of the panels alone beside the panels plus battery |
| Added to existing panels | A battery with its own battery inverter, or a hybrid inverter in place of the one you have | Solar electricity you export today, stored and used instead | How your export is paid, and whether your inverter needs replacing |
| Battery only | A home battery charged from the grid | Charging on a cheap rate and using it at the peak rate | Whether a time-of-use tariff suits your home |
A battery charged from a cheap tariff with no panels is the subject of our guide to a home battery without solar panels.
Adding a Battery to Existing Solar Panels
Yes, a battery can be added to an existing solar system. A 10 kWh battery added to existing solar panels costs about £8,900 fitted at the DESNZ median (April 2025 to March 2026), and a new inverter is extra when the system needs one.
The saving depends on how your export is paid, because a battery stores electricity you would otherwise export. Pick "Yes, already fitted" in the calculator, type the size of your panels in kWp and choose your export arrangement. The table shows what the calculator then counts as lost.
| Export arrangement | Export income lost for each kWh stored |
|---|---|
| Smart Export Guarantee or another metered export tariff | The export rate for that kWh |
| Feed-in Tariff with deemed export | None, because the payment follows the generation meter |
| No export payment | None |
The same battery can therefore pay back faster for an owner on deemed export than for an owner on a metered export tariff. The calculator does not ask for the inverter type or the year the panels were fitted, so it adds no inverter replacement cost.
Which Battery Sizes Does the Calculator Price?
The calculator does not work out the size of battery you need: you pick a size, and it prices that size and works out its payback. The table sets out the three size groups the calculator prices.
| Size on the label | DESNZ size band | Watch out for |
|---|---|---|
| About 5 kWh | Under 6 kWh nominal | A higher price per kWh than a larger battery |
| About 10 kWh | 6 to under 11 kWh nominal | Panels fill it less often in December than in June |
| 13.5 kWh and above | 11 kWh nominal or more | The 13.5 kWh and 15 kWh batteries show the same price (see the price table) |
Usable capacity is the capacity on the label times the battery's maximum depth of discharge, taken from its datasheet first (MCS MGD 003). The calculator asks for the size on the label and shows the usable capacity as its own line. Panels fill a large battery less often in December, so each extra kWh of storage earns less in winter. The smallest and largest choices have their own pages: the 5 kWh battery and the 20 kWh battery. Choosing a battery size in kWh is covered in full under what size solar battery you need.
How Much Can a Solar Battery Save a Year?
A solar battery saves the solar electricity you store and use in the evening instead of buying it, valued at your unit rate minus the export rate you would otherwise earn, less the energy lost in charging. The calculator uses the price cap unit rate of 26.32p per kWh and an export rate of 13p per kWh, unless you type your own.
A battery stores the surplus the panels make in the day and releases it in the evening. Self-consumption, the share of your solar electricity used at home, rises as a result. A full battery sends the remaining surplus to the grid as before. The stored kWh are no longer exported, so a battery reduces export income, and that loss is part of the sum. Round-trip efficiency is the share of stored electricity that comes back out, and the calculator uses 89% (our rule: the lower of two makers' datasheet figures).
The result card above shows self-consumption without and with the battery, the export lost and the yearly saving for your own answers. The next question after the saving is whether extra panels or a battery pays back faster.
Solar Batteries and Time-of-Use Tariffs
On a time-of-use tariff a solar battery can charge at the cheap rate overnight and power the home at the peak rate, so it earns in winter too. A time-of-use tariff charges a different unit rate at different hours. The calculator counts this second saving when you type your own day rate and night rate and pick your cheap hours. It shares the battery between solar and the grid, fills it from the grid once a night at most, and never counts grid electricity as exported. It then measures the result against your bill on your present single rate, because a two-rate tariff can have a dearer day rate for everything else you buy. With the two rate boxes empty, cheap-rate charging is not included and the result card says so; the battery only route then shows a price with no saving. Tariffs with three price bands are not modelled. Tariffs change, and the import tariff changes the saving, which is the subject of our guide to the best electricity tariff for solar and a battery.
How Long Does a Solar Battery Take to Pay Back?
A solar battery takes its installed price divided by its yearly saving to pay back, in years. The result card shows your payback years, and the verdict compares them with a battery warranty length of 10 years (our rule: the shortest warranty length the makers state, not a measured life).
| Verdict | What the result card says | What decides it |
|---|---|---|
| Good fit | The battery pays back well inside the warranty length battery makers give | Payback well inside the battery's warranty length |
| Borderline | The battery pays back in the last years of the warranty length battery makers give | Payback in the last years of the battery's warranty length |
| Poor fit | The battery takes longer than the warranty length battery makers give to pay back, or adds no yearly saving | Payback longer than the battery's warranty length, or no saving |
A Poor fit means the battery does not earn back its price before it wears out, on the rates used. Whether a battery earns back its cost is weighed in full under whether a solar battery is worth it. The panels have a payback of their own, and that separate sum is explained under how many years solar panels take to pay back.
The Battery VAT Clock: What Changes on 1 April 2027
An installed home battery carries 0% VAT until 31 March 2027 and 5% from 1 April 2027 (HMRC VAT Notice 708/6). On a battery of £8,900 the 5% rate adds £445. The result card shows your price before and after the change, with the price after it rounded to the nearest £100. Batteries share the solar VAT rule, and which batteries qualify is set out on our page about VAT on solar and battery installs.
Grants and Loans for a Home Battery
The Warm Homes: Local Grant in England funds a battery only alongside solar panels, for households that meet its income and energy rating rules. The calculator assumes you pay the full price. Eligibility for each scheme is on our page about solar and battery grants.
Get a Free Survey for a Solar Battery
When you are pricing panels too, a Good fit or Borderline result would lead to a survey, in three steps.
- You request a survey after your result.
- Leads 2 Trade arranges the survey.
- An installer gives you the quote after the survey.
You will get phone calls. That is how surveys are arranged. We are paid by Leads 2 Trade Limited when a homeowner we refer asks for a survey. You are never charged. It does not change our figures.
We do not refer tenants or Poor fit results. Leads 2 Trade has not confirmed that it takes requests for a battery only or for a battery added to existing panels, so those two routes show no survey offer today. The request form is not open on this site yet.
How We Work Out Your Battery Estimate
We work out your battery estimate in six sums, each from a named input.
- Price: the size you pick is the size on the label (nominal capacity). It is multiplied by the DESNZ median price per kWh of nominal capacity for the size band (April 2025 to March 2026). The usable capacity, which the saving is worked on, is the label size times a usable share of 90%, the MCS MGD 003 default where the datasheet gives none. A battery is never priced below the largest battery of the band beneath it. The result is rounded to the nearest £100.
- Stored solar: our own self-use model gives the share of your generation used at home with and without the battery. The difference is what the battery delivers.
- Charged electricity: the delivered kWh divided by a round-trip efficiency of 89% (our rule: the lower of two makers' datasheet figures).
- Extra yearly saving: delivered kWh x the unit rate, minus charged kWh x the export rate.
- Cheap-rate charging, only when you type a day rate and a night rate: the kWh the battery moves from the day rate to the night rate x the day rate, minus the kWh bought to do it x the night rate. If the two-rate tariff costs more for the rest of your electricity than your present rate, that cost is taken off the saving. If it costs less, that gain is shown and not counted for the battery.
- Payback: price / yearly saving, set against a battery warranty length of 10 years.
Yearly use is your own figure or Ofgem's typical medium value of 2,500 kWh a year. The solar system is the size you type, or the labelled example size when you are pricing panels too. The worked examples behind these sums are our own, not an official body's. The estimate leaves out a recommended size, tariffs with three price bands, the battery's charge power, backup hardware, an inverter replacement for panels you already have, battery wear and a price range around the median.
Solar Battery Warranty Length: The Short Answer
The verdict uses a battery warranty length of 10 years, our rule: the shortest warranty length the battery makers state, not a measured life. Ask for the warranty terms in writing. Payback is the price divided by the yearly saving; the warranty length only sets the verdict. Battery life in detail is in our guide to how long solar batteries last.
Power Cuts: Only With Backup Hardware
A solar battery powers a home in a power cut only when backup hardware is fitted: a backup gateway or changeover switch that isolates the home from the grid, or, on a Duracell battery, a critical circuit board that lets it supply a set number of circuits. The calculator has no backup option, so it adds no cost for backup hardware. What backup costs and covers is the subject of our guide to solar battery backup in a power cut.
Home Battery Types and Brands
Home battery types differ by cell chemistry, and brands differ on price per usable kWh and on whether the maker is still trading. The calculator prices the battery by size band only. It names no battery brand and uses no supplier battery price. Ask any installer who honours the warranty if the maker stops trading. Brands are set side by side on our page of home batteries compared on price per kWh.
How a Home Battery Is Installed
A home battery is installed and commissioned by an installer, who usually registers it with the local network operator (Energy Saving Trust). A system up to 3.68 kW per phase is notified under G98 after fitting, and a larger one needs a G99 application before fitting (Energy Networks Association). Fitting adds labour to the battery cost, and the steps are in our guide to solar battery installation.
Solar Battery Questions
What is a solar battery?
A home battery that stores electricity, from your solar panels or the grid, so you can use it later instead of buying it at the time. Sizes are given in kWh.
Do you need a battery with solar panels?
No. Panels work without one.
Can you install a solar battery yourself?
A battery connects to the grid, so the network operator must be told (G98 or G99).
Is the battery estimate a quote?
No. It is an estimate from public, dated data and our own stated assumptions. Installers give the quote after a survey; wiring, location and backup hardware can change the price.