Most used EV buyers never do this. It requires no tools, no apps, and no technical knowledge just two noted readings and a simple calculation.
And it tells you more about a battery's real-world performance than almost any other single check.
What it is
The battery consumption check measures how much charge the vehicle uses over a known distance.
By comparing actual consumption against expected consumption based on the vehicle's published efficiency figures you can identify whether the battery or drivetrain is performing as it should.
How to do it
Before the test drive begins, note three things: the state of charge percentage shown on the display, the estimated range shown, and the odometer reading. Write them down.
Drive at least five to eight miles covering a mix of urban and faster road driving. At the end, note the new state of charge, new range estimate, and new odometer reading.
Calculate miles driven ÷ percentage of charge consumed = miles per percentage point. Multiply by 100 to get an approximate effective range. Compare against the vehicle's real-world range expectation WLTP × SoH × 0.80.
What normal looks like
The effective range calculated from your consumption check should be broadly consistent with your pre-calculated expectation.
Variation of 10 to 15% is normal driving style, temperature, and route profile all affect energy consumption. A result within this range suggests the battery and drivetrain are performing as expected.
What abnormal looks like
A result significantly below expectation the vehicle consuming charge much faster than it should for the distance covered may indicate a battery cell imbalance, a battery management system fault, or a drivetrain inefficiency.
It warrants further investigation before purchase.
A range estimate that drops faster than miles covered losing twenty miles of estimated range for every ten miles driven suggests the vehicle's own battery management system has a pessimistic view of its battery's health. This is not proof of a serious fault, but it is a signal worth investigating.
