When Buying a Used EV, Battery Usage (Cycle Count) Matters More Than Mileage

Many consumers judge the condition of a used car only by age and mileage. However, for electric vehicles, the most accurate indicator of battery health is the total charge/discharge amount — the Cycle Count.

An EV battery gradually degrades after a certain number of charge/discharge cycles. Therefore, even if two vehicles have the same mileage, the one with more accumulated cycles can show faster degradation.

The important point here is that EV motors are extremely efficient. With efficiency above 90%, the actual driving energy consumption is much lower than that of internal combustion engine (ICE) vehicles. Instead, HVAC systems (air conditioning and heating), electronic devices, and standby power take up a much larger share of total energy consumption.

In fact, some users leave the vehicle turned on while parked, or keep camping mode or HVAC running for long periods. Such habits do not appear on the odometer, but they quickly increase the cycle count and accelerate battery degradation.

For example, suppose Sentry Mode consumes about 10% of the battery per day. If two users rarely drive:

• User A always keeps Sentry Mode on

• User B always keeps it off

After only 5 days, User A will have consumed 50% of the battery, despite the odometer (ODO) not having increased at all.

Therefore, when evaluating the value of a used EV, the critical factor is not mileage, but how many charge/discharge cycles have accumulated.

Another often-overlooked point is that even without driving, a car left parked at high battery level and high temperature for a long time can degrade much faster than a high-mileage vehicle.

Cycle Count Formula:

Cycle Count = Charged Energy or Discharged Energy / Battery Rated Capacity

Example:

Battery rated capacity = 60 kWh, If you charge/discharge 50% (30 kWh) twice a day: Cycle Count = 30/60 + 30/60 = 1