What is a charging curve?

When you plug a vehicle into a DC fast charger, the charging speed changes over time during a session.

It’s possible to visually represent this by plotting the charging rate over time. This graph is called a charging curve (although it doesn’t always resemble a curve).

A typical charging curve shows high-speed charging when the battery is low and gradually slows down as the battery gets fuller. The vehicle’s Battery Management System manages this curve and protects the battery from undue stress.

The vehicle's peak charging rate is typically achieved only when the battery's charge level is between 10% and 50%.

This may surprise a new owner, who expects the EV to charge at the speed listed. Furthermore, the charge rate markedly declines past 80%, resulting in a prolonged charging period for the remaining twenty percent.

What you need to know:

• The charging curve varies between EV models.

• In this situation, it’s the vehicle dictating the speed (not the charging station)

• In general, the emptier the battery, the faster it charges.

• Charging beyond 80% greatly slows the process (and will inconvenience others waiting to charge).

• Colder temperatures will slow down charging speed.