Do Electric Cars Lose Charge While Parked?

Do EV batteries drain when not in use?

Many EV owners wonder if electric cars lose charge when parked and not in use, with concerns that the battery in an electric car will run out of charge even when it’s turned off, but is it justified?

To give you a short answer, no. If your battery is charged enough, this won’t be a problem. If it’s sat idle for a month, you’ll likely lose only a small percentage of the battery’s total.

We’ll explore the topic in more detail here, so you know what to expect from an EV that has been stationary for some time.

Understanding EV battery drain

Battery drain in EVs refers to the gradual loss of charge when the vehicle is not in use. Batteries in electric cars are typically made of lithium-ion which can store a high amount of energy for its weight, making it popular with EVs.

Lithium-ion batteries do naturally discharge a small amount of energy. Factors like battery age and state of health can increase the self-discharge rate, but it shouldn’t be a cause for concern. The energy lost is minimal and won’t lead to a dead battery unless you left your EV on a very low charge. In addition to the gradual drain, monitoring systems running in the background also contribute to the slow drain.

Causes of EV battery drain while parked

EV battery drain can have a number of causes. Here are a few factors affecting electric cars when parked:

• Battery Management System (BMS) – In some EVs, the BMS continuously monitors and maintains battery health. This can include heating the battery in very low temperatures or cooling it in extremely hot weather, which requires power even when parked.

• Connectivity features – Modern EVs have services for updates and remote monitoring, which connect via Wi-Fi and use battery power even when the car is off.

• Cabin conditioning – Some EVs maintain cabin temperature for comfort, which can drain the battery if set to activate while parked.

• External temperature – Batteries are sensitive to temperature extremes. Very cold or hot weather can compromise battery health over time, reducing the capacity to hold charge effectively.

Tips to prevent battery drain when parked

Wondering what you can do to prevent unwanted battery drain? Minimise loss of charge in your parked EV with these practical tips:

• Proper storage – Park your EV in a garage or another temperature-controlled environment to protect it from weather extremes. Consistent, moderate temperatures help reduce the battery's need to regulate its temperature and protect battery health.

• Battery health monitoring – Regularly check the battery's state of health. Most EVs have built-in diagnostics that provide insights into battery performance and health. Addressing any issues early can prevent excessive drain.

• Adjust settings – If your EV has features like scheduled charging or energy saving modes, use these tools to minimise battery drain. Disable unnecessary features such as cabin preconditioning when the vehicle is parked for extended periods.

• Right level of charge – Keeping your EV between 20% to 80% of charge helps to maintain good battery health, which reduces the rate of drain when parked. We recommend charging to or close to 80% if you’re planning to leave your car stationary for some time (e.g. when going on holiday) to avoid dropping too low.

Want to know more about electric car batteries? Check our guide on how EV batteries work.