Electric Car Battery Faults To Look For Before Buying
Know what to watch for before you hand over your money. Here are the most common battery faults found in used electric vehicles — and how to check for each one properly.
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Why this matters: None of these faults are reliably detectable on a standard test drive. Proper diagnosis requires professional equipment connected directly to the battery management system.
7 Common Electric Car Battery Faults
These are the faults our technicians find most often when inspecting used EVs before purchase.
Battery Degradation
Loss of usable capacity over time and use, meaning the car can't travel as far as it could when new.
Cell Imbalance
Individual cells within the battery pack ageing or performing unevenly, which can accelerate degradation and reduce reliability.
Cleared Warning Lights
A warning light that's been reset on the dashboard without the underlying fault being fixed.
Slow Or Faulty Charging
A worn onboard charger or damaged charge port that reduces charging speed or causes intermittent failures.
Cooling System Faults
Thermal management issues that can accelerate battery wear and increase the risk of overheating during use or charging.
Insulation & High Voltage Faults
Leakage or breakdown in the high voltage system's insulation, wiring or connectors — a serious safety and cost concern.
Prior Accident Or Repair Damage
Previous accident damage or incorrect repair work involving the battery pack, wiring or high voltage components.
Quick Buyer's Checklist
Before you commit to buying, make sure these have all been properly checked — not just visually, but with a real diagnostic test.
- Measured battery capacity (kWh) compared to original spec
- State of Health (SOH) percentage
- Cell balance and individual cell condition
- Full live and stored fault code scan
- Charging speed and charge port condition
- Cooling and thermal management system
- Insulation resistance / high voltage safety check
- Remaining battery warranty status
- Signs of prior accident or repair work
Don't Guess — Get It Checked Properly
Every fault on this list can be found with the right diagnostic equipment before you buy. Get in touch today and buy with confidence.