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Charging a Mercedes-Benz CLA on Intelligent Octopus Go: cost per night and per year

Last checked: 15 October 2026 · SmartShift UK

Mercedes-Benz CLA 250+ · 85.0 kWh usable · 4.24 mi/kWh

One night (6 h)

188 miles

44.4 kWh for £3.37

Typical night

39p

5.2 kWh for 21.9 miles

8,000 miles at 7.6p

£143 a year

1.8p a mile

Same miles at the cap

£497 a year

6.2p a mile at 26.32p

Unit cost only, at the 7.6p overnight rate (23:30–05:30) and a 7.4 kW home charger. “Typical night” is the average day’s driving at 8,000 miles a year (8,000 ÷ 365 = 21.9 miles). Standing charge and charging losses are not included.

The Mercedes-Benz CLA was the eighth best-selling battery electric car in the UK in September 2026, with 1,921 registrations (SMMT, preliminary figures). On EV-Database’s real-world figure of 236 Wh a mile it is the 4th most efficient of the 142 cars in EV charging costs by car, so it costs £25 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 59.5 kWh, which takes about 8 h 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 Mercedes-Benz CLA 250+ (2025-2026), available since May 2025. Source: EV-Database, checked 15 October 2026.
Consumption: 236 Wh a mile, which EV-Database marks as an estimate. 1,000 ÷ 236 = 4.24 miles per kWh, the same figure as the Mercedes-Benz CLA row in the 142-car table.
Usable battery: 85.0 kWh.
Home charging: 7.4 kW on a single-phase 32 A supply. EV-Database gives 0–100% as about 13 h 30 min at that rate and 43 h 30 min 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 × 4.24 mi/kWh = 188 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 ÷ 4.24 = 5.2 kWh, which costs 39p overnight. A week is 36.2 kWh, less than one full night of charging (0.8 nights).
From a 3-pin granny lead (2.3 kW), the same six hours add 13.8 kWh, about 59 miles, for £1.05. See granny charger vs wallbox.

A year at 8,000 miles

8,000 ÷ 4.24 = 1,887 kWh. Each cost is energy × rate, rounded to the pound, the way the 142-car table rounds.

Mercedes-Benz CLA 250+: unit cost only, 15 October 2026
Where the kWh comes from	Rate	8,000 miles	Per mile
Intelligent Octopus Go overnight	7.6p	£143	1.8p
Octopus Go overnight (00:30–05:30)	9.5p	£179	2.2p
Ofgem price cap, Oct–Dec 2026	26.32p	£497	6.2p
Public rapid (illustration)	75p	£1,415	17.7p

Charging overnight on Intelligent Octopus Go instead of paying the cap rate saves £354 a year on these miles. Against an all-rapid year at 75p the gap is £1,272. 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 Mercedes-Benz CLA is number 2 of 37 for the lowest yearly off-peak cost.

Cost of one charge

Mercedes-Benz CLA 250+: cost per charge before losses
Charge	Energy	7.6p	26.32p	75p
10–80% top-up	59.5 kWh	£4.52	£15.66	£44.62
0–100% (usable battery)	85.0 kWh	£6.46	£22.37	£63.75

On a rapid charger, EV-Database puts this car’s 10–80% stop at about 18 min (peak 353 kW DC), taking its range from about 36 to 288 miles. At 75p that stop costs £44.62; the same energy overnight at home is £4.52.

Winter and motorway miles

EV-Database’s 236 Wh a mile is a middle figure. For this car it gives 202 Wh a mile in mild weather (combined), 283 Wh a mile in cold weather (combined, −10°C with heating) and 327 Wh a mile at 70 mph in the cold. EV-Database lists a heat pump as standard.

Cold weather uses about 20% more energy than the middle figure. A whole year at the cold figure would be 8,000 ÷ 3.53 = 2,266 kWh: £172 at 7.6p, or £596 at 26.32p. That is a worst case, not a forecast.
A 200-mile winter motorway run at 327 Wh a mile needs 65.4 kWh: £4.97 if it all went in overnight at 7.6p, or £49.05 at 75p on the road.
One winter night (combined cold figure) adds about 157 miles instead of 188.

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 (189 kWh) went in at the day rate, the year would cost about £195 to £202 instead of £143.
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 Mercedes-Benz CLA 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

Miles a year % charged at home off-peak Public price (p/kWh)

8,000 miles: 1,887 kWh, about £143 a year (all at 7.6p), against £497 all at 26.32p.

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 Mercedes-Benz CLA on Intelligent Octopus Go?

At 7.6p/kWh a 10–80% top-up (59.5 kWh) costs about £4.52 and filling the 85.0 kWh usable battery costs £6.46, before charging losses. 8,000 miles a year is 1,887 kWh, or about £143 if it is all charged in the cheap window, against £497 at the 26.32p price cap.

How many miles does one Intelligent Octopus Go night add to a Mercedes-Benz CLA?

The 23:30–05:30 window is six hours. At 7.4 kW that is up to 44.4 kWh, about 188 miles at 4.24 miles per kWh, for £3.37. In cold weather it is nearer 157 miles.

Can I use Intelligent Octopus Go with a Mercedes-Benz CLA?

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 Mercedes-Benz CLA cost to charge in winter?

EV-Database’s cold-weather combined figure for this car is 283 Wh a mile, about 20% more than its middle figure of 236. A year of 8,000 miles at the cold figure would be about £172 at 7.6p instead of £143. 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).

Not financial advice. These are worked examples from published rates and EV-Database consumption estimates, for planning only. Your own tariff, day rate, standing charge, car, driving and weather will change the numbers. Check your bill and your supplier’s current terms before you switch or buy anything.

Sources

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