Why Intelligent Go is a no-brainer if you've got an EV

When I got my EV, the first thing everyone said was "make sure you get a cheap overnight tariff." Sensible advice. The problem is working out which one. Octopus alone has three tariffs that give you cheap overnight electricity: Go, Intelligent Go and Agile (which is cheap overnight most of the time). Then there's the question of whether the standard Flexible tariff might actually be simpler and good enough.

I ran the numbers across all of them. Intelligent Go wins, and it's not particularly close.

The tariffs, in 30 seconds

Here's the lineup for anyone who hasn't been through the tariff guides yet:

• Flexible Octopus: Flat rate, around 24.5p/kWh all day. Simple. No smart meter required.
• Octopus Go: Cheap five-hour overnight window (typically 7.5p/kWh from 00:30-05:30), higher daytime rate. Needs a smart meter.
• Intelligent Go: Same cheap overnight rate as Go, but the window is six hours (23:30-05:30). If you have a compatible charger or EV, Octopus can also schedule extra cheap-rate slots outside that window. Needs a smart meter and compatible setup.
• Agile Octopus: Half-hourly pricing. Usually cheap at night, expensive at peak times. Unpredictable by nature. Needs a smart meter.

The maths

Let's say you're driving a fairly typical EV. Something like a Tesla Model 3 or a VW ID.3, doing about 8,000 miles a year. That's roughly 2,400 kWh of charging per year (at about 3.3 miles per kWh, which is realistic for UK conditions).

If you charge entirely at home, here's what each tariff would cost you annually just for the EV charging:

Right. So Go and Intelligent Go are the same headline rate for EV charging. Why do I say Intelligent Go is better?

The six-hour window changes everything

Go gives you a five-hour cheap window: 00:30 to 05:30. If your car can't finish charging in five hours, the rest happens at the (higher) daytime rate.

Intelligent Go gives you six hours: 23:30 to 05:30. That extra two hours makes a real difference. Most EVs charge at around 7kW on a home wallbox, which means:

• In 5 hours (Go): you get about 35 kWh. Enough for roughly 115 miles. Fine for most days.
• In 6 hours (Intelligent Go): you get about 42 kWh. That's 130+ miles. Enough to fully charge most EVs from about 20%.

With Go, if you arrive home late with a flat battery, you might not get a full charge before the cheap window ends. With Intelligent Go, it's almost never an issue.

The smart scheduling is the real bonus

Here's where Intelligent Go really pulls ahead. If you have a compatible charger (like an Ohme, Indra or Hypervolt) or a compatible EV (most Teslas, some Volkswagens, others being added regularly), Octopus can automatically schedule your charging to happen at off-peak rates even outside the normal window.

You plug in, tell the app what time you need the car ready, and Octopus handles the rest. It might charge a bit at 11pm, pause, then pick up again at 2am when the grid is quieter. You don't need to think about it. You just wake up to a charged car.

This is genuinely useful. If you forget to plug in until midnight, Go would give you only five and a half hours of cheap charging. Intelligent Go might find you extra cheap slots during the following morning or afternoon.

What about the rest of your electricity?

This is the bit people forget. The EV tariffs don't just affect your car charging. They set the rate for your whole house. The daytime rate on both Go and Intelligent Go is higher than the Flexible tariff (around 27-28p vs 24.5p).

So you need to think about your total electricity bill, not just the charging cost. If you use a lot of electricity during the day (working from home, high-usage appliances), the higher daytime rate eats into your overnight savings.

For most EV owners, though, the overnight savings on charging far outweigh the slightly higher daytime rate. We're talking about saving £400+ a year on charging versus paying maybe £30-50 extra on daytime use. The maths is clear.

The tariff comparison tool can help you check the exact rates for your area.

Why not Agile?

Agile is cheap overnight too. Sometimes cheaper than 7.5p. Sometimes you even get negative rates (Octopus pays you to use electricity). Sounds great on paper.

The problem is consistency. Agile rates change every half hour and you only find out the next day's prices at 4pm the evening before. Some winter evenings, Agile overnight rates have hit 15-20p. Not often, but enough to make it unpredictable.

If you're the kind of person who will check tomorrow's prices and set up your charging schedule accordingly, Agile can beat Intelligent Go. Realistically, though? Most people want to plug in and forget about it. Intelligent Go gives you a guaranteed cheap rate every single night, no checking required.

The verdict

If you have an EV and a home charger, Intelligent Go is the obvious choice. You get:

• A guaranteed 7.5p/kWh rate for six hours every night
• Smart scheduling that finds you extra cheap slots when available
• Enough time to fully charge most EVs from nearly empty
• Annual charging costs around £180 vs £588 on the flat rate

Standard Go is fine if your charger or car isn't compatible with the smart scheduling. You still get the cheap rate, just in a shorter window. Flexible is only worth it if you barely charge at home. Agile is for tinkerers who enjoy optimising things.

For everyone else, Intelligent Go is the answer. It's the one I use. The savings are genuine and you don't have to think about it.