Why won't my car charge at the charger's full power?

The slower of the two limits wins — the car's onboard charger (for AC) or its DC curve, the battery temperature, and the state of charge all cap the rate. A 150 kW charger only helps if the car can accept 150 kW at that moment.

How long to charge overnight at home?

A typical 7 kW home charger adds roughly 25-30 miles of range per hour, so a near-empty battery is usually full in 8-10 hours — comfortably within an overnight charge.

Is it faster to charge when the battery is warm?

Yes. A cold battery accepts less power, so fast charging in winter is slower. Many cars precondition the battery on the way to a planned fast charger to speed things up.

What does 'miles of range per hour' mean?

It converts charging power into distance: power in kW divided by the car's consumption gives range added per hour. It's an intuitive way to see how much driving a given charging session buys you.

How Long Does It Take to Charge an EV?

Published 1/21/2026 · 3 min read · Car calculators

Marco Bianchi — Home, DIY & motoring writer at OneKitly

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In short

Charging time ≈ energy you need to add (kWh) ÷ charger power (kW). Adding 40 kWh on a 7 kW home charger takes about 5-6 hours; the same on a 150 kW DC fast charger takes roughly 20 minutes for the bulk of it. Fast charging deliberately slows above 80% to protect the battery, so trip charging usually targets 10-80%.

An electric-car charge point with its digital readout lit. — smart-me AG · Pexels · Pexels

Charging time is battery energy needed divided by charger power. See how home AC and public DC compare, and why fast charging slows past 80%.

The basic formula

Charging time is the energy you add divided by the power delivered: hours ≈ kWh ÷ kW. If you need 40 kWh and the charger gives 7 kW, that's about 5.7 hours before losses. Real charging is a bit slower because some energy becomes heat, so add roughly 10-20%.

Home AC vs public DC

Home charging on AC (around 7 kW) is slow but perfect overnight — you wake to a full battery and never think about it. Public DC fast chargers (50-350 kW) exist for trips, adding a couple hundred miles in the time of a coffee. Most drivers do the vast majority of charging cheaply at home and only fast-charge on longer journeys.

Why the last 20% is slow

DC fast charging tapers as the battery fills: the car reduces power above roughly 80% to avoid stressing the cells. That's why the 10-80% window is the sweet spot on a trip — it grabs most of the range in the least time. Charging to 100% is best saved for slow home charging before a long departure.

Worked with our own calculator

EV charging time calculator

Given

Battery capacity (kWh): 60 kWh
Charger power (kW): 7.4 kW
Current charge (%): 20%
Target charge (%): 80%

Result

Charging time (hours): 5.405

These figures are produced by the calculator below, not typed in by hand — they are recomputed whenever the tool changes.

Run it on your own figures →

Frequently asked questions

Why won't my car charge at the charger's full power?: The slower of the two limits wins — the car's onboard charger (for AC) or its DC curve, the battery temperature, and the state of charge all cap the rate. A 150 kW charger only helps if the car can accept 150 kW at that moment.
How long to charge overnight at home?: A typical 7 kW home charger adds roughly 25-30 miles of range per hour, so a near-empty battery is usually full in 8-10 hours — comfortably within an overnight charge.
Is it faster to charge when the battery is warm?: Yes. A cold battery accepts less power, so fast charging in winter is slower. Many cars precondition the battery on the way to a planned fast charger to speed things up.
What does 'miles of range per hour' mean?: It converts charging power into distance: power in kW divided by the car's consumption gives range added per hour. It's an intuitive way to see how much driving a given charging session buys you.

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