Combining a smart EV charger, solar panels, a home battery, and the Octopus Intelligent tariff in one installation takes more planning than fitting a charger on its own. Here’s what a finished setup looks like, what each part does, and one wiring detail that catches a lot of installations out: stopping your battery from quietly feeding your car instead of the grid.
What is Octopus Intelligent?
Octopus Intelligent is Octopus Energy’s smart EV tariff. It links to a compatible charger through an app and schedules your car to charge during the cheapest overnight hours, currently as low as 7p per kWh. You set a target charge level and the time you need the car ready, and the tariff handles the scheduling from there.
If you’ve also got solar panels and a battery, the same overnight rate can top up the battery too, so it’s ready to run the house through the next day. Set up correctly, the savings come from several directions at once.
What each component does
The EV charge point
Octopus Intelligent works with a range of compatible smart chargers, including the myenergi Zappi, Wallbox, Ohme, and Hypervolt. Once the charger is linked through its app and your Octopus account, Octopus sends it a schedule for the cheap overnight period. Many of these chargers also have a solar diversion mode: if the panels are producing more than the house needs during the day, the charger sends that surplus straight to the car instead of letting it go to the grid.
Main consumer unit and solar consumer unit
Most installations like this use two separate boards. The main consumer unit covers the household circuits: lighting, sockets, the shower. The solar and battery system runs from its own dedicated board. Keeping them apart makes the generation and storage circuits easier to identify, and makes maintenance and fault-finding simpler later on.
Henley blocks
The incoming supply from the grid arrives as a single set of meter tails. Henley blocks are junction points that split that supply so it can feed both consumer units. Without them, only one board can be connected to the meter tails directly, so the Henley blocks are what make a clean two-board setup possible.
Smart meter
A smart meter is a requirement for Octopus Intelligent. It sends Octopus your usage data and is how the tariff tracks what you’re importing from and exporting to the grid. If you don’t already have one, Octopus arranges installation as part of signing up.
Generation meter
Separate from the smart meter, a generation meter records how much electricity your solar panels produce. This is required for the Smart Export Guarantee (SEG), the scheme that pays you for surplus solar exported back to the grid. Without it, you can’t claim SEG payments.
CT clamps
CT (current transformer) clamps measure the current flowing through a cable without being wired into the circuit; they simply clip around it, with an arrow on the casing showing which way the current should flow. In a setup like this, one clamp usually sits on the incoming supply cable, and another on the solar generation output. Together, these readings tell the battery system how much the house is using, how much the panels are producing, and whether the property is currently importing from or exporting to the grid.
How that data reaches the charger and battery depends on the brand. Some accept a wired CT connection directly. Others use a wireless sender: the myenergi Harvi, for example, transmits clamp readings to a Zappi without needing a data cable run between the two.
Why your battery might charge your car instead of the grid
This is the part that catches a lot of installations out, and it’s worth understanding before the wiring layout is decided.
A battery system normally manages itself by watching the CT clamp on the whole-house supply and trying to keep that reading at zero: no import, no export. If the house is using more than the panels are producing, the battery covers the shortfall. If the panels are producing more than the house needs, the surplus goes to the battery first and only spills over to the grid once the battery is full.
The problem is that the CT clamp can’t tell the difference between the kettle and the car. If the EV charger is on the same circuit the clamp is monitoring, the battery system reads that load as part of the house’s demand and discharges to cover it, even overnight, when Octopus Intelligent is already charging the car at 7p per kWh specifically so the battery doesn’t have to.
The result is a battery that empties into the car overnight and then has to be topped up again the next day, often at a higher rate or at the expense of solar that could have gone elsewhere.
There are two ways to deal with this:
- Reposition the CT clamp. If the EV charger and the battery system are wired through two separate pairs of Henley blocks, the CT clamp can be placed so it only monitors the household circuits, not the charger. The battery then has no visibility of the car’s demand and won’t try to cover it. This only works with two separate pairs of Henley blocks, so it’s worth specifying at the planning stage rather than retrofitting later.
- Use the manufacturer’s app logic. Some systems, including GivEnergy where the charger and battery are both GivEnergy, or a Home Assistant setup, let you tell the battery directly when the car is charging so it stands down for that period. This is more flexible if the wiring is already in place, though it depends on the manufacturer supporting it.
For most Octopus Intelligent households, repositioning the CT clamp is the simpler and more reliable fix, and it costs very little extra to include if the system is being installed from scratch.
How it all works together
At night, Octopus Intelligent schedules the car to charge at the cheap rate, drawing from the grid rather than the battery. The battery management system can do something similar, topping itself up overnight ready for the morning before the panels start producing.
During the day, the CT clamps measure what the panels are generating against what the house is using. Any surplus can be diverted to the car for free through the charger’s solar mode, with the battery taking whatever’s left over for use that evening once generation drops off and grid rates rise again.
The smart meter records everything coming in and going out, feeding data to Octopus for billing and to the SEG meter for export payments. Once it’s all set up correctly, the system runs itself. Plugging the car in is about all you need to do.
What does an installation like this cost?
A full setup, smart EV charger, dedicated solar/battery consumer unit, two pairs of Henley blocks, CT clamps, and the associated metering, is typically a full day’s work for a qualified electrician. The electrical installation cost usually sits in the region of £800–£1,500, not including the battery system or solar panels themselves. The exact figure depends on the existing installation, the distances involved, and what metering is already in place.
If you’re planning to combine EV charging with solar or battery storage and want to avoid your battery quietly feeding your car overnight, get in touch and we can advise on the right setup for your home. We install across Bristol and South Gloucestershire.
