EV charging time

What it's for

To know how many hours it takes to charge, from a home socket (2-3 kW), a wallbox (7-22 kW) or a fast charger (50-350 kW).

Note

The calc assumes ~10% loss. In DC fast charging, past 80% the speed drops a lot: real times can be longer.

Why the hours never add up

The theoretical sum is capacity divided by power: 60 kWh at 7 kW is just under nine hours. In practice it takes longer, for three reasons: conversion losses (about 10%), the power the on-board charger actually accepts, and the current your home wiring can supply.

The commonest limit is the car's on-board charger: many cars accept at most 7.4 kW on alternating current, so plugging them into a 22 kW post does not charge them three times faster. A fast post only helps if the car can take that power.

The last 20% costs as much as the first 50%

On a DC fast charger the power is not constant: it starts high and tapers as the battery fills, to protect the cells. From 10 to 80% takes twenty to thirty minutes; from 80 to 100% can take just as long again.

That is why on a trip it pays to stop more often and charge less: two 20-minute stops cover more miles than one 45-minute stop. The practical rule is to leave at 80%, and save the full 100% for slow charging at home, the night before a long drive.

Home socket, wallbox, public post

An ordinary domestic socket (2.3 kW) is not designed for hours of continuous load: it works, but on old wiring it gets hot, and on a large battery it needs the whole night and more. It is the emergency answer, not the everyday one.

A 7.4 kW wallbox is the sweet spot: it only fits inside a small supply contract if the installation has been upgraded, but it fills an average battery overnight. DC posts of 50 kW and up belong on motorways, where time is worth more than the price per kWh.

Nearby tools

To see how many miles you really have left there is Electric car range, and for the comparison with a tank of petrol Electric or petrol: cost per km. Every cost for the year sits in Yearly car cost.