Rapid charging etiquette and efficiency
Getting in, getting charged and getting out.
You'll learn
- Explain rapid charging etiquette and efficiency clearly and accurately
- Read the numbers that define the behaviour
- Apply the idea to a real charging session
Overview
Charging bays are shared infrastructure. A little planning makes journeys faster for you and everyone behind you.
In depth
- Precondition on approach
- Arrive with a low state of charge to use the fast part of the curve
- Charge to the level you need, not to full
- Move the car promptly when the session ends
- Return the cable to its holster
- Report faulty posts through the network app
Calculator
Charging Time Calculator
How long a session takes between two states of charge, including charger efficiency.
kWh
%
%
kW
%
Energy required
36.0kWh
Time
0.78h
Time
47min
Formula
t (h) = capacity × (target − start) ÷ 100 ÷ (power × efficiency)Only the energy between the two states of charge has to be delivered. Losses in the cable, on-board charger and cells mean the wall power is higher than the power reaching the cells, so we divide by the efficiency.
Example: A 60 kWh pack charged from 20% to 80% needs 36 kWh. At 50 kW and 92% efficiency: 36 ÷ (50 × 0.92) ≈ 0.78 h ≈ 47 minutes.
- Real DC sessions taper above ~60% SOC, so the result is optimistic for target values above 80%.
- AC charging is limited by the car's on-board charger, not by the wallbox.
- Cold packs accept far less power until preconditioning has warmed them.
Key takeaways
Remember this
- Arrive low, leave at 70–80%.
- Preconditioning saves everyone time.
- Reporting faults keeps networks working.
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