Used EV Battery Health: What to Check Before You Buy in Australia
Electric vehicle batteries don't last forever. Like all lithium-ion batteries, they degrade with use — losing capacity, and therefore range, over time. The difference between a well-maintained EV battery and a poorly maintained one can be tens of thousands of dollars in effective vehicle value.
Yet most used EV buyers in Australia never verify battery health before purchase. Here's what you need to know.
How EV Battery Degradation Works
Lithium-ion battery degradation occurs through several mechanisms:
Cycle degradation — each full charge-discharge cycle causes a small amount of irreversible chemical change inside the cells. After hundreds of cycles, total capacity measurably decreases.
Calendar ageing — batteries degrade even when not in use, particularly when stored at high or low states of charge. A vehicle left at 100% charge for extended periods ages faster than one kept at 50–80%.
Thermal stress — repeated DC fast charging generates heat. Vehicles without active thermal management, or those fast-charged in hot conditions, age faster.
Depth of discharge — regularly draining a battery to near-zero accelerates degradation compared to partial discharge cycles.
What the Numbers Mean
Most EV manufacturers publish expected battery degradation curves. A typical figure: 70–80% of original capacity after 8 years or 160,000 km (whichever comes first), covered under warranty.
A vehicle with 30% degradation has 70% of its original range. For a Tesla Model 3 Long Range with a 350km WLTP range, that means 245km real-world range. If the seller is quoting 350km, you need to verify the claim.
What to Look For in a Vehicle History Report
A standard PPSR search provides no battery health information. To verify an EV's condition before purchase, your vehicle history check should include:
The National VIN Check Green Report
The National VIN Check Green Report ($34.95) covers all of this alongside the full Gold-tier checks: PPSR finance encumbrances, WOVR write-off history, stolen vehicle status, live registration, market valuation, ANCAP safety rating, and reliability score.
It's the only Australian vehicle history report that includes dedicated EV and hybrid green credential data as a standard section.
Practical Steps Before Buying a Used EV
A $2 PPSR search is not a vehicle history check. For a used EV, the Green Report is the right tool.