Which tariff is best with a home battery?
Jason Hawthorne, CEO at ESME
Rates checked October 2026 · 6 min read · Last updated 22 October 2026
In short
For a battery, the best tariff is the one with the biggest gap between its cheap overnight rate and the price you would otherwise pay. If you have an electric car, Intelligent Octopus Go at about 8p a unit is hard to beat. Without a car, look at British Gas Charge Power or Agile Octopus, and at Octopus Flux if you also have solar.
For your house
Which tariff wins at your house?
Two minutes. You'll see your result on screen.
Key facts
Cheapest overnight rates
About 6.7p to 9.5p a unit, but most need an electric car
Price a battery replaces
26.32p a unit, the price cap from 1 October 2026
Most a 10kWh battery could save
About £669 a year, before battery losses
What you need
A smart meter, which your supplier fits for free
If you have solar
Choose on the export rate too, not just the cheap rate
What is a time of use tariff?
A time of use tariff charges a different price for electricity at different times of day. Overnight, when demand is low, it is cheap. In the late afternoon and evening, when everyone is cooking and the lights are on, it is at its most expensive.
A battery makes that gap pay. It fills up in the cheap hours and runs the house through the expensive ones, so you buy the same electricity at a fraction of the price. You need a smart meter for this, and your supplier fits one for free.
Which tariffs work best with a battery?
The cheapest overnight rates are sold as electric car tariffs, and most of them check that you have a car or a compatible charger. That splits the choice in two.
Intelligent Octopus Go
Cheap rate
About 8p
Cheap hours
11.30pm to 5.30am
Who can get it
Homes with a compatible electric car or charger
EDF GoElectric
Cheap rate
6.66p
Cheap hours
11pm to 6am
Who can get it
Homes with an electric car
British Gas EV Power
Cheap rate
9.5p
Cheap hours
Midnight to 5am
Who can get it
Homes with any electric car
British Gas Charge Power
Cheap rate
Half price
Cheap hours
Midnight to 5am
Who can get it
Homes with a battery, no car needed
Agile Octopus
Cheap rate
Changes every half hour
Cheap hours
Usually overnight and on windy days
Who can get it
Anyone with a smart meter
Octopus Flux
Cheap rate
About 16p
Cheap hours
2am to 5am
Who can get it
Homes with solar and a battery, with paid export at peak
Rates as published in October 2026, with no VAT on electricity until March 2027. Rates vary by region, so check yours by postcode. Flux rates are an average of seven cities from July 2026.
Agile is the most flexible choice without a car. Its price follows the wholesale market, it is capped at 100p a unit, and on some nights it goes below zero, when you are paid to use electricity. A battery that charges on the cheapest half hours does well on it, but you take the risk of an expensive week.
How much could the right tariff save?
Take a 10kWh battery on Intelligent Octopus Go. Every unit it stores at about 8p replaces a unit you would have bought at the 26.32p price cap rate.
The sum, for a 10kWh battery on Intelligent Octopus Go
Price avoided
26.32p
Cheap price paid
8p
Saved per full charge
£1.83
Every day for a year
£669
That is the most it could save, not the typical saving. Batteries lose about a tenth of the energy on the way in and out, and few homes use a full 10kWh outside the cheap hours every day, so the real figure is lower. Allowing for losses alone brings it to about £632.
How do I choose the right one?
- 1Match the cheap hours to your battery. A 10kWh battery charging at around 3kW fills in about three and a half hours, so a five or six hour window leaves room to spare.
- 2Count your car in. An electric car opens up the cheapest tariffs, and the same cheap hours then fill the battery as well as the car.
- 3If you have solar, look at export. What you are paid for spare power can be worth more than a lower overnight rate. See what an export tariff is.
- 4Check the exit fee. Fixed tariffs can charge you to leave early. Intelligent Octopus Go has a £50 exit fee.
- 5Work it out for your house. Your usage, roof and car decide the answer, which is what the journey does.
Questions people also ask
Can I switch tariff after my battery is fitted?
Yes, at any time. Check any exit fee on your current tariff, and make sure your battery is set to charge in the new cheap hours.
Can I get a cheap overnight tariff without an electric car?
Yes, but fewer. British Gas Charge Power needs a battery instead of a car, Agile Octopus only needs a smart meter, and Octopus Flux needs solar and a battery. See cheap tariffs without an electric car.
What happens when the price cap goes up?
The price cap sets the most you pay a unit on a standard tariff. When it rises, the gap between it and a cheap overnight rate usually grows, and so does what a battery saves. See what the price cap rise means.
Sources
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Figures are for Great Britain and were checked on the date above. Prices change, so check the latest before you decide. This is general information, not financial advice.
Your house, not an average one
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