Charging a Kia EV4 on Intelligent Octopus Go: cost per night and per year

On EV-Database’s real-world figure of 252 Wh a mile it is the 19th most efficient of the 142 cars in EV charging costs by car, so it costs £15 a year less to run off-peak than the site’s typical EV (277 Wh a mile, £168 at 7.6p).

Its on-board AC charger takes up to 11 kW, so a 7.4 kW single-phase wallbox runs at its full 7.4 kW. A 10–80% top-up is 54.6 kWh, which takes about 7 h 30 min at 7.4 kW: longer than the six-hour window. One night adds 44.4 kWh; a bigger top-up runs past 05:30 or needs a second night (or Octopus’s smart slots, below).

The numbers this page uses

• Car: EV-Database lists this version as the Kia EV4 Hatchback 81.4 kWh (MY27) (2026), available since October 2026. Source: EV-Database, checked 15 October 2026.
• Consumption: 252 Wh a mile, which EV-Database marks as an estimate. 1,000 ÷ 252 = 3.97 miles per kWh, the same figure as the Kia EV4 row in the 142-car table.
• Usable battery: 78.0 kWh (an EV-Database estimate) (nominal 81.4 kWh).
• Home charging: 7.4 kW on a single-phase 32 A supply. EV-Database gives 0–100% as about 12 h 30 min at that rate and 40 h ours from a 3-pin plug (2.3 kW).
• Tariff: Intelligent Octopus Go, 7.6p/kWh from 23:30 to 05:30, plus up to six hours of smart charging a day at 7.6p (Octopus, checked 15 October 2026).
• Comparisons: Ofgem’s October–December 2026 cap average of 26.32p/kWh, and 75p/kWh as an illustration of public rapid charging (not a published average).

Worked example: one night on Intelligent Octopus Go

• Window: 23:30 to 05:30 is 6 hours. At 7.4 kW that is 7.4 × 6 = 44.4 kWh.
• Miles: 44.4 kWh × 3.97 mi/kWh = 176 miles.
• Cost: 44.4 kWh × £0.076 = £3.37. The same energy at 26.32p would be £11.69.
• An average day at 8,000 miles a year is 21.9 miles: 21.9 ÷ 3.97 = 5.5 kWh, which costs 42p overnight. A week is 38.6 kWh, less than one full night of charging (0.9 nights).
• From a 3-pin granny lead (2.3 kW), the same six hours add 13.8 kWh, about 55 miles, for £1.05. See granny charger vs wallbox.

A year at 8,000 miles

8,000 ÷ 3.97 = 2,015 kWh. Each cost is energy × rate, rounded to the pound, the way the 142-car table rounds.

Charging overnight on Intelligent Octopus Go instead of paying the cap rate saves £377 a year on these miles. Against an all-rapid year at 75p the gap is £1,358. For comparison, Zapmap’s September 2026 average pay-as-you-go price for rapid and ultra-rapid chargers was 79p/kWh (Zapmap Price Index). Octopus Go’s 9.5p rate is from Octopus’s tariff data, compared in Intelligent Octopus Go vs Octopus Go.

Of the 37 cars in this series, the Kia EV4 is number 8 of 37 for the lowest yearly off-peak cost.

Cost of one charge

On a rapid charger, EV-Database puts this car’s 10–80% stop at about 33 min (peak 135 kW DC), taking its range from about 31 to 248 miles. At 75p that stop costs £40.95; the same energy overnight at home is £4.15.

Winter and motorway miles

EV-Database’s 252 Wh a mile is a middle figure. For this car it gives 217 Wh a mile in mild weather (combined), 300 Wh a mile in cold weather (combined, −10°C with heating) and 347 Wh a mile at 70 mph in the cold. EV-Database lists a heat pump as an option, not standard, so check the spec of the car you drive.

• Cold weather uses about 19% more energy than the middle figure. A whole year at the cold figure would be 8,000 ÷ 3.33 = 2,402 kWh: £183 at 7.6p, or £632 at 26.32p. That is a worst case, not a forecast.
• A 200-mile winter motorway run at 347 Wh a mile needs 69.4 kWh: £5.27 if it all went in overnight at 7.6p, or £52.05 at 75p on the road.
• One winter night (combined cold figure) adds about 148 miles instead of 176.

When the 7.6p doesn’t apply

Intelligent Octopus Go charges 7.6p for the six-hour home window and for the car’s smart-charging slots, which Octopus schedules and can fall outside 23:30–05:30. Anything else, including charging you start yourself outside a slot, is billed at your day rate. On today’s 12-month fixed version, Octopus’s tariff data gives day rates of 34.95p to 38.82p depending on region, and standing charges of 42.29p to 66.74p a day (Octopus tariff API, Direct Debit; Octopus lists this version as on sale until 20 October 2026).

• If 10% of this car’s 8,000-mile energy (202 kWh) went in at the day rate, the year would cost about £208 to £216 instead of £153.
• The standing charge is paid every day whatever you charge, so it is left out of all the totals here. See standing charges explained.
• Whether the Kia EV4 can be smart-charged directly depends on Octopus’s current compatibility list. Octopus says you can connect a compatible car or a supported charger in its app, so check the car (or your charger) in Octopus’s checker before switching.

Try your own miles

The rest of your miles are priced at the public figure you enter. Other cars: all 37 cars on Intelligent Octopus Go, or the homepage calculator for your own rates.

Questions people ask

How much does it cost to charge a Kia EV4 on Intelligent Octopus Go?

At 7.6p/kWh a 10–80% top-up (54.6 kWh) costs about £4.15 and filling the 78.0 kWh usable battery costs £5.93, before charging losses. 8,000 miles a year is 2,015 kWh, or about £153 if it is all charged in the cheap window, against £530 at the 26.32p price cap.

How many miles does one Intelligent Octopus Go night add to a Kia EV4?

The 23:30–05:30 window is six hours. At 7.4 kW that is up to 44.4 kWh, about 176 miles at 3.97 miles per kWh, for £3.37. In cold weather it is nearer 148 miles.

Can I use Intelligent Octopus Go with a Kia EV4?

It depends on Octopus’s current list of compatible cars and chargers. Octopus says you connect a compatible car or a supported charger in the Octopus app, and you need a smart meter sending half-hourly readings. Check the car or charger in Octopus’s eligibility checker before you switch.

How much more does a Kia EV4 cost to charge in winter?

EV-Database’s cold-weather combined figure for this car is 300 Wh a mile, about 19% more than its middle figure of 252. A year of 8,000 miles at the cold figure would be about £183 at 7.6p instead of £153. Real years mix summer and winter.

Is the standing charge included?

No. You pay the standing charge every day whatever you charge, so it is left out. On Intelligent Octopus Go’s current 12-month fixed version it is 42.29p to 66.74p a day depending on region (Octopus tariff data, 15 October 2026).

Sources

• EV-Database, Kia EV4 Hatchback 81.4 kWh (MY27) (2026) (consumption, battery, charging times, cold-weather figures)
• EV-Database, UK real-world consumption list (Wh/mile)
• Octopus Energy, Intelligent Octopus Go (checked 15 October 2026)
• Octopus Energy tariff API, Intelligent Octopus Go 12M Fixed October 2026 v1 (regional day rates and standing charges)
• Octopus Energy, Octopus Go
• Ofgem, price cap 1 October–31 December 2026
• Ofgem, energy price cap unit rates and standing charges (1 October–31 December 2026)
• Zapmap, Price Index (September 2026, updated 7 October 2026)

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