Just like a mobile phone battery, an electric car's battery pack will lose capacity over time. If you lease the batteries, you won't have to worry about the cost of replacing them in the future – when they drop below a certain capacity, they'll be replaced free of charge. However, we're finding that most electric cars aren't losing battery capacity as quick as expected. Many owners find that there's no need to replace the batteries, even when the car's nudging 10 years old. As battery leasing is expensive, we'd recommend buying a car with the batteries owned outright.