Tariffs · Octopus Flux
Octopus Flux with a battery: plan the 4 to 7pm sale
Flux has three prices a day. Power is cheap from 02:00 to 05:00 and dear from 16:00 to 19:00, and the export rate peaks in those same three hours. A battery on Flux has one job: arrive at 16:00 with the right amount in it. Too little and you buy at the peak. Too much sold and the house runs short at 19:30. Suntide works that out every night, for your house.
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The shape of Flux
| Hours | Import | Export |
|---|---|---|
| 02:00 to 05:00 | 15.31p | 4.99p |
| 05:00 to 16:00 | 25.51p | 10.11p |
| 16:00 to 19:00 | 35.72p | 29.32p |
| 19:00 to 02:00 | 25.51p | 10.11p |
One region's rates as Octopus published them on 5 September 2026, per kWh. Yours differ by region and change over time. Suntide reads your own from your Octopus account, export included, so nothing is typed in. Octopus sets who is eligible for Flux.
What Suntide does on Flux
Decides how much to charge at 2am
From tomorrow's solar forecast for your roof and how your house draws power on days like tomorrow. A sunny day needs less from the grid. A dull one needs the battery full.
Plans the sale in the peak
It prices every half hour of the day and sells from the battery between 16:00 and 19:00 when that pays after battery wear. It keeps enough back to carry the house through the evening, tested against a colder, dimmer day than forecast.
Shows the plan before it runs
Tomorrow is drawn tonight, each block priced, with the reason in words: “selling 16:00 to 19:00 at 29.32p”. Nothing on your inverter changes unless you apply it.
The safeguards
- It never sells on a guessed export rate. Only a rate read from your account or your bill.
- Battery wear is priced into every kWh it plans to discharge. More if you chose long battery life as a goal.
- Your reserve is a floor. The plan is tightened until the house still gets through a pessimistic day.
- Selling grid-charged power is a setting you hold. It starts on for Flux, because Flux allows it, and you can turn it off.
- Your bill is checked against your own half hours, at your Flux rates.
What your inverter allows
Inverters differ in what they accept from outside. See what yours allows.
| Takes a full schedule | Charge and discharge windows set from Suntide with the charge current, and read back from the inverter. The inverter's clock is kept right, which Flux's fixed hours depend on. |
| Takes charge windows only | Some inverters do not take a forced export window from outside. The 2am charge is planned and set for you, and the evening sale stays with the inverter's own work mode. |
| Read only | The plan is drawn and priced. You set the times in the maker's app with Suntide's steps, and Suntide checks from the data that it worked. |
It earns the switch first
Suntide starts in shadow. It changes nothing. Each evening it decides what it would do, and the next day it prints what that would have saved or cost against what happened. After 7 measured nights you can let it steer for you. A steered change is read back from the inverter, logged, and reported to you. One pause switch stops all of it.
Pricing · What Suntide changes on your inverter · Everything Suntide works with · How it compares