As energy prices remain volatile, homeowners across the South East are increasingly looking for smarter ways to control when and how they buy electricity. One of the most effective strategies combines battery storage with off peak and time of use tariffs – particularly intelligent options such as Octopus Flux.
In this guide, SolarTherm UK explains how charging your solar battery with off peak tariffs works, why it improves savings and how it fits into a modern solar PV system.
What Are Off Peak and Time of Use Tariffs?
Off peak tariffs – often called time of use tariffs – charge different electricity rates depending on the time of day and demand on the grid. Electricity is typically cheaper when national demand is low, such as overnight or during periods of high renewable generation.
Low overnight import rates are ideal for battery charging with some dropping as low as 7p per kWh for a set time period. Higher peak rates will be charged during high demand periods (usually evenings when most people arrive home and start using electricity), these can be charged as high as 45p per kWh.
For homes with battery storage, these tariffs unlock far greater flexibility than standard flat rate pricing.
How Battery Storage Works With Off Peak Tariffs
A solar battery is not limited to storing excess solar generation. It can also:
- Charge from the grid when electricity is cheapest
- Discharge during peak rate periods to power your home
With the right inverter and control settings, your system can automatically:
- Charge the battery during off peak hours – pre-set to match your tariff cheap rates
- Power your home from stored energy during peak tariff periods
- Minimise expensive grid imports during peak periods
This approach reduces exposure to high daytime and evening tariffs, especially valuable in winter months when solar generation is lower.
Why Octopus Flux is Popular for Solar Battery Owners
Octopus Flux is specifically designed for households with solar panels and battery storage. It combines import and export pricing with clear time windows. Key benefits include:
- Cheap off peak import periods for battery charging
- Premium export rates during peak grid demand – where you can discharge your battery
- A structure that rewards flexible energy use
When paired with a correctly sized battery, Flux allows homeowner to arbitrage electricity – buying it cheaply, storing it, using it or exporting it when prices are highest.
Solar and Battery and Time of Use: A Smart Energy Strategy
For South East homeowners, this setup delivers multiple advantages:
Lower Energy Bills
Charging batteries overnight on off peak tariffs reduces reliance on high cost peak electricity.
Increased Energy Independence
Stored energy gives you greater control, even when solar production is low.
Better Use of Battery Capacity
Instead of sitting partially empty in winter, batteries remain active year round.
Future Ready Homes
Time of use optimisation aligns with the UK’s shift toward smart grids and flexible demand.
Is Charging from the Grid Still “Green”?
While grid charging may sound counter-intuitive, off peak electricity is increasingly coming from overnight wind generation and surplus renewable energy during low demand. In practice, charging a battery off peak can still reduce overall carbon intensity – especially when it replaces peak time fossil fuel generation.
What You Need to Make It Work
To charge batteries on off peak tariffs effectively, your system should include a compatible hybrid or battery inverter and smart battery controls and scheduling ability. You battery needs to be correctly sized for your household usage, ensuring you store enough energy for your evening and overnight needs while your solar panels are not generating electricity.
At SolarTherm UK, we recommend shopping around to find the best time of use tariff that suits your needs and lifestyle. Octopus Flux gives multiple off peak time frames suitable for charging your battery, with two windows with preferential rates for exporting, encouraging you to discharge your battery during peak demand periods. Alternatively, for those who like more control and like to watch current rates, Octopus Agile allows you to charge you battery on the lowest rates and export at the highest rates, with rates changing to meet current demand and wholesale prices.
Charging Solar Batteries on Off Peak Tariffs: Is It Worth It?
For many South East homeowners, the answer is yes. When battery storage is paired with the right tariff, savings are more predictable, exposure to energy price rises is reduced and your solar PV system performs optimally year round.
Speak to SolarTherm UK
If you already have solar – or are planning a new installation – SolarTherm UK can help assess whether off peak charging is right for your property.
Contact SolarTherm UK today for a free, no obligation quote and design, tailored to your property, usage and future energy needs. No hard sell, just honest, expert advice.
Your home. Your energy. Your future.
