How do I use a home battery with Octopus Agile?

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Use a home battery with Octopus Agile by charging during lower-priced periods and reserving that energy for more expensive household demand, while leaving space for useful solar generation. Agile prices are half-hourly, meaning each half-hour has its own unit price. The best schedule depends on those prices, your battery limits and tomorrow’s demand and sunshine, so a fixed overnight timer can miss opportunities.

Understand the price you are moving energy between

A tariff is the pricing agreement with your supplier. Agile is an import tariff: it determines what buying grid electricity costs. A unit of electricity is a kilowatt-hour, or kWh, a measure of energy. Export is electricity sent from your home to the grid, and the payment for it comes from your export agreement. Do not assume an Agile import price is also an export price.

The attraction of storage is that the time you buy energy can differ from the time you use it. You still need to pay for the energy lost when charging and discharging. Buying at a lower headline price is therefore only useful if the delivered energy replaces something more expensive, or earns enough permitted export income to cover its costs.

A real price example, with its limits

For London, region C, on 31 August 2026, Octopus's public API recorded −1.62p per unit at 13:00 and 42.84p at 17:00. The price gap was 42.84 − (−1.62) = 44.46p per unit, roughly a 44p swing. That example shows why assuming the cheapest electricity always arrives overnight is unreliable.

A negative import price means the tariff credits eligible consumption in that interval. It does not mean every household can turn the full price gap into profit. Your battery must have room, its charging power limits how much it can take, and stored energy has losses. These observations are for that region and date; they are not prices for every Agile customer or a forecast of the next day.

Build a schedule around the household

Read the published prices for your own region and put them beside your expected household demand. Identify the expensive periods you want to cover, then work backwards to the charge needed. Account for any energy deliberately reserved for backup. A large charge target is not automatically better if you will not use the energy before another cheaper opportunity arrives.

Add the solar forecast. If a bright day is expected, it may be sensible to buy only enough energy to reach the solar-generating period and leave capacity for the surplus. If the forecast weakens, more grid charging may become useful. A plan must also consider direct household use of solar: generation used immediately in the home is not available to charge the battery.

Check whether the equipment can follow the plan

Confirm that your inverter, which controls energy conversion and battery operation, supports the grid-charging schedule you intend. Check usable capacity, charging power, discharge power, minimum charge and any export limit. A cheap interval may not be long enough to fill the battery. A battery can also hold enough energy overall yet lack the power to cover simultaneous appliances.

For manual operation, enter charging windows and targets in the supported controls, then confirm that the battery actually follows them. Avoid competing schedules in different apps. Keep a usable fallback schedule for missing price data or a disconnected controller. Protective settings and installation limits should remain within the manufacturer's and installer's requirements.

Do not chase a price without considering what follows

An expensive period can tempt you to empty the battery early. But the next period of household demand may be more expensive still, or there may be no cheap recharge opportunity before you need it. Similarly, buying extra energy at a negative price can occupy space that would otherwise hold useful solar generation.

Compare the net cost over the whole planning period. Include the cost of charging, the later import avoided, energy losses and the value of any export you give up. If you can already move a flexible appliance directly into a cheap period, compare that option too. Running it directly avoids routing its energy through storage, while leaving battery capacity for demand you cannot move.

Automate the decisions that keep changing

PredBat re-plans every 5 minutes over a 48-hour horizon, at 5-minute resolution. It tests battery levels in 0.25 kWh steps against three solar forecasts. Those are planning settings, not a promise that future prices or sunshine are known, and they do not mean the supplier bills in 5-minute intervals. The service costs £9.99/month; whether it is worthwhile depends on the extra benefit over your current controls.

Automation is useful because the decisions interact: prices, remaining charge, forecast sunshine and household demand can all change the right action. It cannot create a profitable price difference where none exists or overcome the physical limits of the installation. The tariff and equipment details still need to be configured correctly.

Judge the result in money, not activity

Review your supplier's billed import and export alongside the battery history. Look for fewer expensive imports and a lower net cost under comparable conditions, rather than simply more charging cycles. A day with little battery movement may be sensible if prices are flat and solar already covers demand.

Agile and Intelligent Octopus Go are different tariffs; a schedule appropriate to one should not be copied into the other. Before changing tariff, consider the household as a whole, including flexible loads, export terms and the times you cannot shift. The best battery schedule serves that household, rather than a dramatic price chart.

How do I use a home battery with Octopus Agile? | PredBat