Electric car journey planner: where to stop to charge, to what % and for how long

How the journey is worked out

The road route is calculated first, then rapid chargers (50 kW or more, with your car’s connector) within 2 miles of it are found. With the car’s battery, consumption and maximum charging power, every combination of stops and charging percentage at each one is tried, and the one that gets you there soonest is kept, counting driving, detours and charging. Each stop adds a fixed 10 minutes (leaving the motorway, finding the charger, plugging in and paying) and a stop is never planned for less than 5 minutes of charging: it is better to charge a little more at the previous stop.

The last kWh are the slowest. A car charges at full power up to about 50%; after that the power drops and, from 80 to 100%, it can fall to a quarter. That is why short stops from 10 to 50–60% are almost always faster than filling the battery.

The official consumption figure is no good for long journeys. The official figure (WLTP) comes from a mixed town and country cycle; at motorway speeds an electric car uses about 40% more and, in cold weather, another 20% more. So the planner starts from the car’s official figure, multiplied according to speed (×1.20 at about 60 mph, ×1.30 at about 70 mph and ×1.40 at about 75 mph), and you can replace it with the real consumption your car shows.

Prices are each operator’s pay-as-you-go reference tariff, without a subscription. It is an estimate: wind, hills, how loaded the car is or driving style change the result. Before setting off, charge at home at the cheapest time and check the charging point map.