What should I set as the battery charge window on Intelligent Octopus Go?

Set a timed grid-charge window for the core cheap period, 11:30pm to 5:30am, and use self-consumption or a similar mode outside that window so the battery can power the house at the day rate. Do not expect the battery to follow the car's extra smart-charge slots unless you are on a product such as Charge Pack that can dispatch the battery.

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Intelligent Octopus Go and your home battery: why it drains, or does not charge overnight

Q: Does Intelligent Octopus Go tell my home battery when to charge?

Not on a standard Intelligent Octopus Go set-up. The cheap rate for the whole home is guaranteed between 11:30pm and 5:30am. Extra smart-charge slots are scheduled for the car or charger. When those slots fall outside the core window, Octopus also applies the cheap rate to the rest of the house for that half-hour, but a typical battery app cannot see those slots in advance. You usually set a fixed charge window in the battery app. Charge Pack is a separate Octopus product that can schedule a compatible battery.

Q: Why is Intelligent Octopus Go draining my home battery?

Octopus says the battery usually cannot tell whether a power demand is coming from the car or from the rest of the house. If the car starts charging, many batteries treat that as household load and discharge into the car. That can empty the battery just when you wanted it for the daytime rate. Official suggestions include moving the battery's CT clamp so it no longer sees the EV charger, which is an electrician's job, or pausing the battery in its app.

How the tariff works, checked against Octopus's own help pages on 15 November 2026. Rates below are from Octopus's public tariff data the same day, for London unless we say otherwise. This is general information for Great Britain, not personal advice, and not a recommendation to switch. Northern Ireland is not covered here.

Affiliate disclosure:

Intelligent Octopus Go can be a cheap way to charge a car, and the same overnight rate can fill a home battery for the next day. The catch is that the tariff talks to the car or charger, not to a typical battery. If the two are not set up to work together, the battery can empty into the car, or sit idle all night and never take the cheap electricity.

This guide explains the difference between the guaranteed cheap window and the extra smart-charge slots, the usual reasons a battery misbehaves, and a short checklist to work through before you call anyone. We do not use affiliate links on energy tariffs. All supplier links below are plain links, except one clearly labelled Octopus Energy referral. For a comparison of EV, solar export and battery tariffs, see our EV, solar and battery tariffs guide.

How Intelligent Octopus Go actually works

Octopus describes two cheap-rate mechanisms, and they are easy to mix up:

A core off-peak window for the whole home: 11:30pm to 5:30am, every night. Anything the house uses in that window, including a home battery on a timed grid charge, is billed at the off-peak rate. This window is fixed and reliable, which is why it is the one to put in the battery app.
Up to six hours of smart charging for the car or charger in each 24-hour period. Octopus schedules those hours for when it expects power to be cheaper or greener. They may fall inside the core window, outside it, or a mix of both.

When a smart-charge slot is scheduled outside 11:30pm to 5:30am, Octopus also applies the off-peak rate to the rest of the house for that half-hour, as long as it is within the six-hour allowance. That is useful if you are awake and can run the dishwasher. It is not something a typical battery can follow automatically, because the slots are not a published timetable. If you try to “catch” them by leaving the battery in a free-for-all mode, it will often discharge into the car instead.

Bump or boost charging of the car is billed at the day rate, even if it happens overnight.

Rates we verified today from Octopus's public tariff data, for London:

Intelligent Octopus Go, London rates, checked 15 November 2026. Other regions differ, especially on standing charges.
Version	Off-peak rate	London day rate	London standing charge	Notes
Intelligent Octopus Go Max (variable)	6.5p/kWh, all regions	38.27p/kWh	42.56p/day	No exit fee. The official “from 6.5p” rate sits on this version.
Intelligent Octopus Go 12-month fix	7.9p/kWh, all regions	40.44p/kWh	42.56p/day	£50 exit fee. Rates fixed for 12 months.
Intelligent Octopus Go (standard variable)	9.9p/kWh, all regions	34.16p/kWh	42.56p/day	No exit fee. Higher night rate, lower day rate than Max.

For comparison, the Ofgem price cap electricity unit rate, as a GB average for 1 October to 31 December 2026, is 26.32p per kWh, with a standing charge of 54.83p a day. The cap only applies to default and standard variable tariffs. Details are in our energy price cap guide.

Why the battery drains into the car

Octopus has a dedicated help page on this. A solar battery's default behaviour is usually:

Power the home from solar first.
If the house needs more than the solar can provide, the battery steps in.
Only then is power imported from the grid.

The battery typically cannot see whether that extra demand is the washing machine or the car. It treats the EV charge as household load, rule two kicks in, and the battery is emptied. You then have little or nothing left for the daytime rate, and you may be refilling the battery at the wrong time.

Octopus suggests two official fixes:

Move the battery's CT clamp so it sits downstream of the EV charger, “blinding” the battery to the car. This is an electrician's job unless you are competent and happy to do it. Do not move clamps yourself if you are not sure.
Pause or hold the battery in its own app at times when the car might charge. Octopus itself says this is not ideal if you leave the car plugged in to catch bonus cheap slots, because you will not know when those slots are.

If you are on Octopus Charge Pack as well, that is a different set-up. Charge Pack can schedule a compatible battery on the same platform as Intelligent Octopus Go. Check in the Octopus app whether Charge Pack is actually managing your battery before you change schedules yourself.

Why the battery may not charge overnight

If the battery did not fill during 11:30pm to 5:30am, the cause is usually in the battery app or the inverter, not in the Octopus smart-charge schedule. Extra dispatch slots are for the car. A normal battery only grid-charges when you have given it a timed window, or when a managed product such as Charge Pack is controlling it.

Common reasons, in plain terms:

There is no timed grid-charge window, or it is set to the wrong hours. The window to use is 11:30pm to 5:30am, UK local time.
The battery is in eco or self-consumption mode only. Those modes often charge from solar and cover the house, but will not import from the grid overnight unless a timed charge is also set.
The reserve or minimum state of charge is in the way. A high backup reserve can leave little room to charge, or a low charge target can stop the battery before it is full. Check both the minimum reserve and the charge-to target.
The tariff is not set, or is set wrongly, in the battery app. Some apps use a time-of-use or tariff profile to decide when grid charging is allowed. If that profile still says “flat rate” or Economy 7, the battery may never start a cheap-rate charge at 11:30pm.
The schedule disappeared after a firmware update, a power cut, or the clocks changing. Some inverters store schedules in a way that resets or shifts by an hour. If charging failed for the first time after one of those events, open the app and check the times have not moved or vanished.
The inverter is offline. If it has lost Wi-Fi or its connection to the manufacturer's cloud, timed charges often do not run. A solid or flashing fault light, or an “offline” status in the app, is the clue.

A step-by-step checklist

Work through these in order. Stop when you find the fault. This is a self-help list, not a repair manual, and it is not a substitute for your installer.

Confirm in the Octopus app that you are on Intelligent Octopus Go, and note whether Charge Pack is also connected to the battery. If Charge Pack is managing the battery, check Octopus before you overwrite the schedule.
Open the battery or inverter app and check the inverter is online, with a recent “last seen” time and no active fault codes.
Find the charge schedule or time-of-use settings. Set a grid-charge window of 11:30pm to 5:30am, every day, on UK local time. Clear any old Economy 7 or peak/off-peak times that do not match this tariff.
If the app has a tariff or rate-plan setting, set it to a two-rate time-of-use plan with cheap electricity 11:30pm to 5:30am. Do not try to enter the car's extra smart-charge slots, because they change.
Check the mode. You usually want a timed charge overnight, and self-consumption or “use the battery first” during the day. Pure eco or “solar only” modes often will not grid-charge.
Check the reserve or backup level, and the charge-to target. Leave a reserve if you want backup in a power cut, but make sure there is still room to take a cheap overnight charge.
If the battery has been draining into the car, look for a “pause”, “hold”, or “do not discharge” option during known charging times, or speak to an electrician about the CT clamp. Do not move a clamp unless you know what you are doing.
If you also have solar, leave the battery able to take surplus solar during the day once the overnight charge is done. The two systems should not fight: overnight is for cheap grid charging, daytime is for solar first, then the battery, then the grid.
Wait for the next core window, or use any “charge now” test in the app while you are still in the cheap period, and confirm the state of charge rises and the house meter shows import.

GivEnergy, Tesla Powerwall, SolarEdge and others

The setting names differ by brand and by app version, and we have not independently verified every current menu label. Treat the names below as a starting point, and check your own app, the manufacturer's help, or your installer if you cannot find the equivalent.

GivEnergy: look in the GivEnergy app or portal for a timed charge or schedule, plus the operating mode (often eco or self-consumption) and the reserve level. Confirm the inverter is online. We have not verified a GivEnergy-specific Intelligent Octopus Go profile, so set the times yourself rather than assuming a preset is correct.
Tesla Powerwall: look for Time-Based Control or a similar utility rate plan, and enter the 11:30pm to 5:30am cheap window. Also check Storm Watch or backup reserve, which can hold charge back. Confirm the Powerwall is connected to Wi-Fi. Check Tesla's app and help if a menu name does not match.
SolarEdge and other inverters: look for a time-of-use, schedule, or storage profile, and for a grid-charge permission. If the system was commissioned on a different tariff, the old times may still be in there. Check the SolarEdge app, or your installer's portal, rather than guessing.

If your battery is a brand we have not named, the same three checks apply: is it online, is there a timed grid-charge window set to 11:30pm to 5:30am, and is it allowed to import from the grid in that window?

When to contact your installer or the manufacturer

Contact your installer, or the battery manufacturer's support, if:

The inverter stays offline after you have restarted the Wi-Fi and the device, or there is a persistent fault code.
You have set a correct schedule and mode, the inverter is online, and it still does not charge in the core window.
You need the CT clamp moving so the battery no longer sees the EV charger. That is an electrical job.
The system is still under warranty or a workmanship guarantee, and you do not want to change settings that could affect that.

Octopus can help with the tariff, the car schedule and Charge Pack. It cannot usually reprogram a third-party inverter. Your installer or the manufacturer is the right place for that.

FAQ

Does Intelligent Octopus Go tell my home battery when to charge?

Not on a standard set-up. The cheap rate for the whole home is guaranteed between 11:30pm and 5:30am. Extra smart-charge slots are scheduled for the car or charger. When those slots fall outside the core window, Octopus also applies the cheap rate to the rest of the house for that half-hour, but a typical battery app cannot see those slots in advance. Set a fixed window in the battery app. Charge Pack is a separate Octopus product that can schedule a compatible battery.

Why is Intelligent Octopus Go draining my home battery?

Octopus says the battery usually cannot tell a car from the rest of the house. If the car starts charging, many batteries treat that as household load and discharge into the car. Official suggestions are to have an electrician move the CT clamp so the battery no longer sees the charger, or to pause the battery in its app.

I have solar as well as a battery. Does that change the advice?

The overnight window is the same. During the day, let surplus solar charge the battery before you export, unless you are on a tariff that pays more for export at a set time, such as Prime Outgoing or Flux. Those combination rules are in our EV, solar and battery tariffs guide. If a daytime smart-charge slot starts and the battery is in self-consumption mode, it can still empty into the car, so the CT clamp or hold setting still matters.

Could this be a clock or British Summer Time problem?

It can be. Some battery schedules sit on the inverter's clock. After the clocks change, a firmware update, or a power cut, the window can shift by an hour or disappear. Octopus bills Intelligent Octopus Go on the 11:30pm to 5:30am window. If your inverter is an hour out, it may be charging at the day rate, or not charging at all. Check the time in the app against a reliable clock.

Sources

Octopus Energy: Intelligent Octopus Go
Octopus Energy: My Intelligent Octopus Go charge has drained my home battery
Octopus Energy: Intelligent Octopus Go, smart charging and Charge Cap explained
Octopus Energy: how Charge Pack manages your battery
Octopus Energy: public tariff API, checked 15 November 2026, for London unit rates and standing charges on Intelligent Octopus Go Max, the standard variable version, and the 12-month fix
Ofgem: energy price cap unit rates and standing charges
Deal Whizz UK: EV, solar and battery tariffs compared
Deal Whizz UK: energy price cap January 2027 and today's fixed deals
Deal Whizz UK: best heat pump tariffs UK compared

Prices, app menus and eligibility change. Figures in this guide were checked on 15 November 2026 and may already be out of date when you read them. Get a quote for your postcode and read the tariff information label before you switch. This is not financial advice, and it is not a recommendation of any supplier, tariff or installer.

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