Intelligent Octopus Go Integration

Introduction

Netzero integrates with the Intelligent Octopus Go (IOG) EV tariff from Octopus Energy. By providing your Octopus API key and account number, Netzero automatically configures your Powerwall to charge during smart charging slots outside the off-peak window.

This prevents your Powerwall from discharging while your EV charges and maximizes use of cheaper electricity, even outside the 23:30-05:30 night rate.

Setup

• Ensure you are on an Intelligent Octopus Go tariff and have a compatible EV or charger.
• In Netzero, go to Settings > Utility Rate Plan.
• Enter your Octopus API key from your Octopus account; it starts with sk_live.
• Enter your Octopus Energy account number from bills, emails, or the Octopus app, e.g. A-12A34A99.
• Switch on Automate Intelligent Octopus Go.
• Optionally enable Use Backup Mode to charge Powerwall faster to speed up Powerwall charging. See Backup Mode for details.
• Optionally enable Preserve charge instead of charging up to keep the Powerwall’s charge during a scheduled slot without charging it. You might use this option if you prefer to charge up the Powerwall from solar instead of the grid.
• Enable push and/or email notifications in Settings > Notifications to get notified when smart charging slots start and stop. Make sure the Automations notify only when failing toggle is disabled.

Only the Octopus API key and account number are needed to enable the integration: the charging slots come from Octopus. Linking your EV or EV charger to Netzero as well is strongly recommended on the current tariff, where Powerwall charging only starts once the EV is drawing power: Octopus reports the EV power reading with a delay, and a linked device lets Netzero start Powerwall charging as soon as the EV starts (see Powerwall charging follows your EV). See EV Charger Settings for the supported EVs and chargers. Netzero does not need to manage your utility rate plan for this integration, although it can (see Dynamic Electricity Pricing). The integration requires a Netzero subscription.

How it works

Netzero periodically checks for scheduled charging slots. When a slot falls outside the off-peak window (23:30-05:30), Netzero sets the Powerwall backup reserve to 100% so the battery charges. Netzero stores and restores the previous backup reserve after the slot ends. When Backup Mode is enabled, Netzero will change the operational mode instead of the backup reserve setting.

Each configuration change is listed under Automation > Past Runs, and a notification is sent when a slot starts and ends.

On the current Intelligent Octopus Go tariff, two further rules apply, described below: a 6-hour limit on smart charging per day, and Powerwall charging that follows the EV. Netzero detects which version of the tariff your account is on and applies them only where they apply.

Notes

• If you have existing automations for smart charging slots (e.g. “When vehicle charging starts: Set backup reserve to 100%”), pause or remove them to avoid conflicts. API-based integration is more reliable.
• If a charging slot ends during the off-peak window (23:30-05:30), the backup reserve remains at 100% through the window and resets at 05:30 unless another slot is scheduled.
• If a charging slot is fully within the off-peak window, the backup reserve will not be changed. Most systems will not discharge the Powerwall in Savings mode during off-peak hours. If you prefer, you can also add an automation to keep the Powerwall at 100% backup reserve between 23:40 and 05:30.
• If you override the 100% backup reserve while the EV charges, Netzero will not restore the previous reserve to avoid overriding manual changes.
• The Powerwall’s charging rate varies, usually around 1.8 kW per Powerwall in Self-Powered mode, but may be higher in Savings mode. Utility limits may also affect the rate. You can use Backup Mode to increase the charging rate.
• Smart charging slots are shown at the off-peak price in the app’s price charts and in the Energy Cost section.
• A Powerwall grid export cannot be started while a smart charging slot is active.
• Octopus Weekend Happy Hours and Power Down sessions are set up separately, on the same screen. See Octopus Saving Sessions.

Supported EV chargers

Any EV or charger that Octopus schedules smart charging for works with the integration, since Octopus provides the schedule. This includes Ohme chargers: Octopus makes the Ohme schedule available, so Netzero configures the Powerwall for Ohme the same as for any other charger.

If you set up Netzero automations as a workaround for a charger that was previously unsupported (for example “When vehicle charging starts: Set backup reserve to 100%”, or a home-usage-based rule), pause or remove them before switching on Automate Intelligent Octopus Go. The direct integration handles the Powerwall charging, and leaving the old automations in place can conflict with it.

6-hour smart charging limit

Since mid-2026, Intelligent Octopus Go limits smart EV charging to 6 hours per day, measured midday to midday. Octopus moved most existing customers to the new version of the tariff between July and late August 2026. Details are in Octopus’s post Smart charging and Charge Cap explained.

Octopus also offers Charge Cap, a setting in the Octopus app that limits smart EV charging to the 6 hours and avoids charging at peak prices. We recommend turning Charge Cap on. See Enabling Charge Cap helps below for why.

How Netzero’s protection works

Independently of Charge Cap, Netzero adds its own protection on the Powerwall side. Netzero tracks the total time you’ve spent in smart EV charging slots since noon (the cap is measured midday to midday, matching Octopus’s window). When a new slot starts and your day’s total would exceed 6 hours including that slot, Netzero leaves the Powerwall in Preserve Charge for that slot rather than charging it from the grid. This avoids the Powerwall paying peak rates after Octopus has stopped charging the EV at the cheap rate.

Netzero only applies this 6-hour protection when it detects that the new Intelligent Octopus Go rules are active on your account. No action is required on your part.

One decision per slot, which may preserve more than necessary

The 6-hour protection makes a single decision per slot: either charge the Powerwall for the whole slot, or leave it in Preserve Charge for the whole slot. It does not revisit that decision part-way through a slot, which keeps it simple and predictable at the cost of sometimes preserving more battery than strictly required.

This is separate from Powerwall charging follows your EV below, which does keep re-checking during a slot. The two work together: the 6-hour protection decides whether a slot is eligible at all, and the EV check decides which half-hours within an eligible slot the Powerwall actually charges for.

Example:

• You’ve already had 4 hours of smart EV charging today.
• A new 3-hour slot starts. Your daily total would reach 7 hours, exceeding the 6-hour cap.
• Netzero leaves the Powerwall in Preserve Charge for the entire 3-hour slot, even though the first 2 hours of it would still have been within the 6-hour window.

We may refine this in future based on real-world data.

Enabling Charge Cap helps

If Charge Cap is on in the Octopus app, Octopus itself only schedules smart charging up to the 6-hour limit and trims the slot it proposes to fit. The “preserves more than necessary” case above does not occur: Octopus would schedule a 2-hour slot rather than a 3-hour one, the day’s total stays at exactly 6 hours, and Netzero’s protection does not need to engage at all. The Powerwall ends up with more useful charging time, not less.

If Charge Cap is off, Octopus may continue to propose slots that don’t fit the 6-hour budget, and Netzero will fall back on the all-or-nothing behaviour above.

Note: The 6-hour timer only tracks smart EV charging slots. If your Powerwall charges during off-peak outside of smart EV charging slots, this will not count toward the 6-hour limit.

Powerwall charging follows your EV

On the current Intelligent Octopus Go, a smart charging slot outside 23:30-05:30 gives your home the off-peak rate only when the EV is actually drawing power. If the car finishes early, is unplugged, or never starts, Netzero may not charge the Powerwall for some or all of the slot.

Netzero follows the same rule during a slot outside the off-peak window:

• Powerwall charging starts once the EV is drawing power, rather than as soon as a slot appears on the schedule. Netzero uses the EV power reading from Octopus, and, if you have linked a supported EV or EV charger, the charging status reported by that device.
• Netzero re-checks regularly during a slot, so charging can start part-way through a half-hour rather than waiting for the next one.
• Once the EV has drawn power within a half-hour, the Powerwall keeps charging until the end of that half-hour even if the car pauses. Octopus bills in half-hour increments, so the entire period is billed at the off-peak rate as long as the EV charges at some point during it.

What to expect:

• Powerwall charging begins some minutes after a slot starts. Octopus updates the EV power reading periodically rather than continuously, so a car that starts charging on the hour does not show as drawing straight away. Linking a supported EV or EV charger reduces this delay, since Netzero then sees the charging status directly from the device.
• The Powerwall may stop and start again during a long slot, following the car.
• Notifications and Past Runs still show one start and one stop per charging slot, not one per half-hour.

This applies only to the current version of the tariff. On the original Intelligent Octopus Go tariff the whole home gets the off-peak rate for the entire slot whether or not the car is charging, so Netzero charges the Powerwall for the whole slot.

Frequently Asked Questions

Why did the Powerwall not charge during a smart charging slot?

On the current tariff, the two rules above are the usual reasons: the slot would have taken the day’s smart charging past 6 hours, so the Powerwall was left in Preserve Charge, or the EV was not drawing power during the slot. Both are listed with the reason under Automation > Past Runs. Otherwise, check that Automate Intelligent Octopus Go is still on and that your Octopus API key is valid: Octopus API keys can be regenerated from the Octopus account page, which invalidates the previous key.

Why is the Powerwall charging from the grid or discharging to the EV outside a slot?

Outside smart charging slots, Netzero does not change the Powerwall settings for this integration. Charging from the grid at other times is decided by Tesla’s Savings mode based on the utility rate plan, and discharging into the EV happens whenever the Powerwall is above its backup reserve and the home (including the EV) draws more than solar provides. See Why is my Powerwall charging or discharging when I don’t expect it to? in the FAQ, and consider an EV charging automation to preserve Powerwall charge while the EV charges outside a slot.