Maintaining an electric or hybrid car: what needs doing

An electric car has fewer things to replace than a petrol one, but “maintenance-free” is a myth. And a hybrid needs both combustion-engine maintenance and care for its electric system.

Common to EVs and hybrids

• The 12 V battery. Yes, an EV has one too, and a weak 12 V battery is one of the most common reasons a car “won’t start”. It is charged by the DC-DC converter.
• Coolant for the battery, inverter and motor. Level, condition and change intervals vary by model.
• The brakes, which rust more often than they wear out. Details in regenerative braking.
• Brake fluid, usually about every 2 years.
• Tyres: weight and high torque wear them faster. Check pressures monthly and rotate them at the recommended interval.
• Cabin filter and air conditioning, which on many EVs also cools the battery.
• Suspension and steering, which work harder because of the battery’s weight.

On top of that, for hybrids

• Engine oil and filters, as on any car. The engine starts and stops often, so the right oil matters.
• The hybrid battery filter and fan. On many Toyota and Lexus models, the battery is cooled with cabin air. Dust and pet hair clog the filter, the battery runs hot and ages faster. See hybrid battery cooling.
• The inverter cooling circuit, separate from the engine’s on many hybrids, with its own electric pump.
• A hybrid system check: faults, battery module condition, high-voltage insulation.

Signs something is wrong

• Range dropping suddenly, or higher fuel use on a hybrid.
• The battery fan running often and loudly.
• Warning lights, even ones that disappear after a restart.
• Charging taking much longer than before.

The cost differences compared with a petrol car are in EV versus petrol maintenance.