Used EV battery health check Australia: what to test before you buy

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Ask for a battery State of Health report before committing

Australian Government guidance specifically recommends asking the seller or dealership for a battery health report when preparing to buy an EV. State of Health, usually shown as a percentage, compares the battery's present condition or capacity with its original state.

Some vehicles expose battery information through onboard systems or apps, but the Government notes that an independent battery health check may be preferable. The aim is to reduce uncertainty around the individual vehicle rather than rely on assumptions about the model as a whole.

Understand SoH

State of Health is useful, but one percentage does not tell the whole story

Battery State of Health can help quantify degradation, but different manufacturers and diagnostic tools can calculate or expose battery information differently. Treat the number as one input and understand the method behind it.

Also distinguish normal degradation from a fault. EV batteries gradually lose usable capacity over time; that is different from sudden damage, a defective module or a battery-management-system issue.

Warranty

Check the exact battery warranty against age, kilometres and capacity terms

Many new EVs are sold with battery warranties around eight years and a kilometre limit, but the exact terms vary by brand and model. Some warranties also contain a minimum retained-capacity threshold.

For a used EV, confirm whether the warranty transfers to the next owner, whether scheduled servicing or other conditions apply, and whether both the age and kilometre limits still leave meaningful cover.

Real-world checks

Range and charging behaviour can reveal questions worth investigating

A test drive can help you observe energy use, charging behaviour, warning messages and whether the vehicle performs normally, but dashboard range is not a laboratory battery test. Weather, recent driving style, climate control and route history can all affect the displayed estimate.

If possible, inspect the vehicle at a sensible state of charge and verify both AC and DC charging compatibility for the model. Check the charge port, supplied cables and any adapters for damage or unusual wear.

History

Battery confidence is stronger when the whole vehicle history makes sense

Review service records, recall completion, accident history and any high-voltage repairs alongside battery health. A good State of Health result does not remove the need for a normal used-car inspection.

For an EV, the inspection should also consider underbody condition, cooling systems, high-voltage components and manufacturer-specific diagnostics where relevant. Use appropriately qualified technicians rather than attempting to inspect high-voltage components yourself.

Buyer checklist

The evidence pack to ask for before paying a deposit

The objective is to leave as few unknowns as practical. A seller who can provide clear battery, warranty and service information makes the vehicle easier to assess and may make it easier to explain its condition again when you eventually sell it.