Last Updated on October 20, 2026

A home battery off-peak tariff lets you charge a battery overnight when electricity is cheaper, then use that stored energy during the day when prices are higher. With overnight rates ranging from around 7p to 17p per kWh and daytime or peak rates reaching 27p to 52p, the potential savings can be substantial.

For a 5 kWh battery, our calculations suggest savings of £354 to £600 a year if it completes a full cycle every day. A home with solar panels may charge from the grid less frequently, reducing the savings attributable to off-peak charging alone.

We compared tariffs from Octopus Energy, E.ON Next and EDF using published October 2026 prices, alongside Ofgem’s electricity consumption figures.

Quick answer: A 5 kWh home battery charged overnight at 8p to 17p per kWh and used instead of electricity costing 27p to 52p can save approximately £1 to £1.65 per day, or £354 to £600 annually with daily cycling. Many of the cheapest overnight tariffs require an electric vehicle, heat pump or solar panels, so check eligibility before switching.

Key takeaways

• Cheapest overnight rates: EDF GoElectric at 6.66p, Intelligent Octopus Go and E.ON Next Drive Smart at 8p, and Octopus Go at 9.4p.
• Battery efficiency matters: Allowing for 90% round-trip efficiency, Octopus Go 12M Fixed provides a potential saving of 26.8p per kWh shifted.
• Annual savings: Approximately £354 to £600 for a 5 kWh battery, or £709 to £1,200 for a 10 kWh battery, assuming 365 full cycles.
• Whole-bill comparison: Our example household pays £816 annually on Flexible Octopus without a battery, compared with £593 on Octopus Go 12M Fixed with a 5 kWh battery.
• Check eligibility: EV tariffs are not automatically available to battery-only households. Octopus Cosy is designed for electric heating, while Flux requires solar panels and battery storage.

How does a home battery off-peak tariff work?

A home battery off-peak tariff works by taking advantage of different electricity prices throughout the day.

You charge the battery when electricity is cheapest, typically overnight, and discharge it when your household would otherwise be buying more expensive electricity from the grid.

For example, consider Octopus Go 12M Fixed in London.

Its overnight rate is 9.4p per kWh, while its daytime rate is 37.29p per kWh.

A battery is not perfectly efficient. Some energy is lost during charging and discharging.

Tesla’s Powerwall 3 documentation gives a round-trip efficiency of 89%, so we use a rounded assumption of 90%.

To deliver 5 kWh of electricity, the battery needs approximately 5.56 kWh from the grid.

At 9.4p per kWh, that costs approximately 52p.

Buying the same 5 kWh directly during the day at 37.29p would cost approximately £1.86.

That gives a saving of approximately £1.34 per day.

Over a full year of daily charging and discharging, the potential saving is around £490.

However, the actual amount depends on how frequently you use the battery, your electricity consumption and the tariff’s pricing structure.

Which off-peak tariffs work with a home battery?

The table below compares off-peak electricity tariffs available in October 2026.

Octopus rates are based on London pricing, including VAT. Rates vary by region, and tariff eligibility is just as important as the headline overnight price.

Tariff	Cheap-rate hours	Off-peak rate	Day rate	Peak rate	Eligibility
Octopus Flux	2am–5am	16.17p	26.78p	37.38p, 4pm–7pm	Solar, battery, MCS and smart meter
Octopus Cosy Variable	4am–7am, 1pm–4pm, 10pm–midnight	14.12p	28.80p	43.19p, 4pm–7pm	Heat pump or electric heating
Octopus Cosy 12M Fixed	Same as Cosy	16.89p	34.43p	51.64p	Heat pump or electric heating
Octopus Go Variable	12:30am–5:30am	9.40p	34.53p	None	EV and smart meter
Octopus Go 12M Fixed	12:30am–5:30am	9.40p	37.29p	None	EV and smart meter
Intelligent Octopus Go 12M Fixed	11:30pm–5:30am	8.00p	39.29p	None	Eligible EV or smart charger
E.ON Next Drive Smart	Midnight–6am	8.00p	30.82p	None	EV, charger and smart meter
E.ON Next Drive Fixed	Midnight–6am	9.50p	Confirm on quote	None	Smart meter; confirm EV requirements
EDF GoElectric	11pm–6am	6.66p	Confirm on quote	None	Smart meter and EV tariff

Rates reflect the source comparison dated 20 October 2026, including Octopus tariff versions published for 20–21 October. Some rates may change before publication. Prices are in pence per kWh.

Octopus publishes tariff information through its product pages and pricing data, including Octopus Go, Cosy Octopus, Intelligent Octopus Go and Octopus Flux.

E.ON Next confirms that its Next Drive tariffs can be used to pre-charge home batteries, although customers must still meet the tariff’s eligibility requirements.

EDF publishes its GoElectric EV tariff information, but the daytime rate was not available in the source comparison.

Can you get an EV tariff without an electric car?

Do not assume so.

Several of the cheapest overnight electricity tariffs are specifically designed for electric vehicle owners.

Intelligent Octopus Go requires an eligible EV or supported smart charger, while Octopus Go is marketed to EV drivers.

A household with only a home battery should contact the supplier to confirm eligibility before relying on the advertised rate.

Octopus Flux is different because it is designed for homes with both solar panels and battery storage.

If you are considering the equipment itself, our guide to the best home battery storage in the UK compares available options.

How much does a home battery save on an off-peak tariff?

Savings depend primarily on three factors: the difference between overnight and daytime rates, battery efficiency and how much stored electricity you use.

For the calculations below, we assume:

• A 5 kWh usable battery for a medium-consumption household.
• A 10 kWh usable battery for a higher-consumption household.
• 90% round-trip battery efficiency.
• One complete charge and discharge cycle per day.
• Electricity charged overnight and used during the day or peak period.

Ofgem’s typical domestic consumption values put medium electricity consumption at 2,500 kWh annually, equivalent to 6.8 kWh per day.

High consumption is 3,800 kWh annually, equivalent to 10.4 kWh per day.

Tariff	Saving per kWh delivered	5 kWh daily saving	5 kWh annual saving	10 kWh annual saving
Octopus Flux, peak	19.4p	£0.97	£354	£709
E.ON Next Drive Smart	21.9p	£1.10	£400	£801
Octopus Go Variable	24.1p	£1.20	£440	£879
Octopus Go 12M Fixed	26.8p	£1.34	£490	£980
Octopus Cosy Variable, peak	27.5p	£1.38	£502	£1,004
Intelligent Octopus Go 12M Fixed	30.4p	£1.52	£555	£1,110
Octopus Cosy 12M Fixed, peak	32.9p	£1.64	£600	£1,200

Illustrative gross savings against each tariff’s own daytime or peak rate. Figures assume 365 complete cycles annually, no solar charging and enough household demand to use all the stored electricity. They do not include battery purchase costs.

The formula is:

Saving per kWh delivered = daytime rate − (off-peak rate ÷ battery efficiency)

For Octopus Go 12M Fixed:

37.29p − (9.4p ÷ 0.9) = approximately 26.8p saved per kWh.

Multiply that by 5 kWh and 365 days to calculate the annual saving.

What changes if you already have solar panels?

A household with solar panels may charge its battery using surplus solar electricity during spring and summer.

That means fewer days when overnight grid charging is needed.

If you assume approximately 180 grid-charging days instead of 365, the potential annual savings for a 5 kWh battery fall to approximately £175 to £296 across the tariffs in the table.

These are illustrative upper limits for the specified number of cycles, not guaranteed savings.

Actual results may be lower if the battery is not fully discharged, your household uses less electricity than expected or your tariff changes.

Does an off-peak tariff beat the standard electricity rate overall?

A large difference between the day and night rates does not automatically make an off-peak tariff cheaper.

Some tariffs have daytime rates substantially above the standard variable tariff.

To assess the benefit, you need to compare the total annual electricity bill, including standing charges.

Consider a London household using 2,500 kWh annually.

Using Octopus’s published Flexible tariff data and its Go 12M Fixed rates, the following example compares the annual cost.

Setup	Annual electricity cost	Difference from Flexible Octopus
Flexible Octopus, no battery	£816	Baseline
Octopus Go 12M Fixed, no battery	£1,083	£267 more
Octopus Go 12M Fixed, 5 kWh battery	£593	£223 less

The example assumes all electricity on the Go tariff is purchased at the daytime rate when there is no battery, making that the worst-case comparison.

With a battery, 5 kWh of daily demand is shifted into the overnight charging period.

This produces a potential annual saving of approximately £223 compared with remaining on Flexible Octopus without a battery.

That is a more meaningful comparison than the £490 saving against Go’s own daytime rate.

However, it still excludes the purchase and installation cost of the battery.

And because Octopus Go is an EV tariff, a battery-only household should not assume it can access the deal.

Is an off-peak tariff better with solar panels?

For many homes, combining solar panels and battery storage creates more ways to reduce electricity costs.

During sunny periods, the battery can store electricity generated by the solar panels.

During winter or periods of low generation, it can charge using cheaper overnight electricity.

A suitable tariff may also allow battery owners to earn money by exporting electricity during peak periods.

Octopus Flux: charging cheaply and exporting at peak times

Octopus Flux offers three different pricing periods.

In London, the tariff’s October 2026 prices include:

• 16.17p per kWh for overnight imports between 2am and 5am.
• 26.78p per kWh for daytime imports.
• 37.38p per kWh for peak imports between 4pm and 7pm.
• 30.31p per kWh for peak exports between 4pm and 7pm.

The peak export rate is available through Octopus’s published Flux tariff data.

If you buy electricity overnight at 16.17p and export it at 30.31p, the theoretical margin after allowing for 90% battery efficiency is approximately 12.3p per kWh exported.

For 5 kWh exported daily, that is approximately £225 annually.

If the battery follows that pattern for 180 days, the illustrative benefit falls to approximately £111.

These figures exclude additional battery wear, tariff restrictions and any changes in import or export rates.

You should also confirm that the supplier permits the proposed grid-charging and export arrangement.

Our guide to the best SEG export tariffs in the UK explains how Flux compares with other export tariffs.

What will the January 2027 energy price cap mean for battery savings?

Higher daytime electricity prices can make stored electricity more valuable.

For every 1p increase in the daytime rate, a 5 kWh battery delivering a full cycle every day could save an additional £18.25 annually, assuming its overnight charging rate stays unchanged.

However, the savings depend on the difference between the two rates rather than the daytime rate alone.

If overnight rates rise at the same time, some of the additional benefit disappears.

Fixed tariffs offer more predictable rates during the contract period, while variable tariffs can be repriced.

Ofgem’s October to December 2026 average electricity unit rate is 26.32p per kWh, but some off-peak tariffs have substantially higher daytime rates.

Our guide to solar panels vs the energy price cap explains how the forecast January increase could affect electricity savings.

Is a home battery worth buying just for an off-peak tariff?

A battery can reduce electricity costs even without solar panels, but whether the investment pays for itself depends on the upfront price.

According to iHeat’s solar battery cost guide, typical installed prices are approximately:

Battery capacity	Indicative installed cost
5 kWh	£4,000–£6,000
10 kWh	£6,000–£8,000

Using our calculated off-peak charging savings, the simple payback periods are:

Battery capacity	Potential annual saving	Illustrative simple payback
5 kWh	£354–£600	Approximately 7–17 years
10 kWh	£709–£1,200	Approximately 5–11 years

These ranges compare the lowest installation cost with the highest annual saving and vice versa.

They assume the battery completes a full charge and discharge cycle every day and that the tariff remains favourable.

They also exclude battery degradation, maintenance, financing and replacement costs.

A home with solar panels may have fewer opportunities for overnight grid charging because the battery is already storing electricity generated during the day.

That reduces the savings attributable to grid charging alone, although the household may also benefit from using more of its own solar generation.

Before buying a battery, compare the full installation cost against realistic household usage and tariff eligibility.

Our guides to whether solar batteries are worth it, what size solar battery you need and how long solar batteries last can help.

FAQs

Can I charge a home battery on an off-peak tariff without solar panels?

Yes. A home battery can store electricity purchased from the grid overnight and release it when daytime electricity is more expensive.

E.ON Next confirms that its Next Drive tariffs allow customers to pre-charge batteries overnight, although those tariffs are designed for EV customers.

Octopus Flux requires solar panels as well as a battery.

Always check tariff eligibility before switching.

What is the cheapest home battery off-peak tariff?

EDF GoElectric has the lowest overnight rate in our October 2026 comparison at 6.66p per kWh between 11pm and 6am.

E.ON Next Drive Smart offers 8p, while Octopus Go offers 9.4p in London.

However, these are EV tariffs. The lowest overnight rate is not necessarily the cheapest option overall because daytime prices, standing charges and eligibility requirements differ.

Does Intelligent Octopus Go work with a home battery?

Intelligent Octopus Go requires an eligible electric vehicle or supported smart charger.

A home battery may be charged during the cheap-rate period, but owning a battery alone does not establish eligibility.

The October 2026 12-month fixed version offers an 8p overnight rate and a 39.29p daytime rate in London.

Is Octopus Flux better than Octopus Go for a home battery?

It depends on your equipment and electricity usage.

Octopus Flux is designed for solar and battery households. It offers cheaper daytime electricity than Octopus Go and pays higher export rates during the evening peak.

Octopus Go provides a larger difference between overnight and daytime import rates, making it attractive for eligible EV households that can shift significant electricity consumption overnight.

Compare the complete import and export arrangements rather than the overnight rate alone.

What happens to battery savings when the energy price cap rises in January?

If daytime electricity becomes more expensive while the overnight rate stays unchanged, the value of using stored electricity increases.

For a 5 kWh battery cycling daily, every additional 1p per kWh in the daytime rate could add approximately £18 a year to savings.

However, variable off-peak tariffs may also become more expensive, so the actual benefit depends on both rates.

Our Verdict

A home battery off-peak tariff can deliver meaningful savings, but the best option depends on your household’s equipment and electricity consumption.

For eligible EV households, Octopus Go and Intelligent Octopus Go offer some of the largest differences between overnight and daytime prices, with potential annual savings of approximately £490 to £555 for a 5 kWh battery cycling daily.

Homes with heat pumps or electric heating may benefit from Octopus Cosy, while households with solar panels and batteries should consider Octopus Flux.

If you only have a home battery, check supplier eligibility carefully. An advertised overnight rate does not necessarily mean the tariff is available without an electric vehicle.

We would also be cautious about buying battery storage solely to take advantage of off-peak electricity.

Our model suggests simple payback periods of approximately 7 to 17 years for a 5 kWh battery, and those calculations depend on regular charging, continued tariff savings and the battery’s lifespan.

For households planning solar panels, combining generation and storage can offer additional benefits beyond off-peak charging.

Eco Happy can help you explore suitable solar and battery systems and compare installation options for your home.

Sources

• Octopus Energy – Flux Import Tariff Data
• Octopus Energy – Flux Export Tariff Data
• Octopus Energy – Cosy Variable Tariff Data
• Octopus Energy – Cosy Fixed Tariff Data
• Octopus Energy – Go Variable Tariff Data
• Octopus Energy – Go Fixed Tariff Data
• Octopus Energy – Intelligent Go Fixed Tariff Data
• Octopus Energy – Flexible Tariff Data
• Octopus Energy – Go
• Octopus Energy – Cosy
• Octopus Energy – Intelligent Octopus Go
• Octopus Energy – Flux
• E.ON Next – Drive Fixed vs Drive Smart
• E.ON Next – Next Drive Help
• E.ON Next – EV Charging Tariff Announcement
• EDF – Electric Vehicle Tariffs
• EDF – GoElectric
• Ofgem – Energy Price Cap Unit Rates
• Ofgem – Typical Domestic Consumption Values
• Tesla – Powerwall 3 Technical Documentation
• iHeat – Solar Battery Storage Costs UK