Category - Ev Chargers
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Paul Holdsworth, Engineer

31 Jan : Updated 17 Apr ● 6 min read

Do electric cars lose charge when parked?

Electric cars are rapidly gaining in popularity, and with a long list of environmental and financial benefits, as well as the government’s goal to phase out petrol and diesel vehicles over the coming years, it’s not difficult to understand why

Without the traditional fuel gauge that many drivers are accustomed to, it can be a bit of a learning curve to understand how your shiny new electric car maintains its charge and how long a single charge will last. 

On average, a fully charged electric car battery should be able to take you approximately 200 miles - but what about the charge lost while the car is parked?

Cars are made to be driven, and leaving your electric vehicle parked for any length of time will gradually deplete the battery power and whilst this loss might be nominal at first, be assured that it will build up over time.

The longer the electric car is left sitting idle, the more miles are trickling away, and soon, that average will look a lot shorter. 

Thankfully, you can do a few things to protect your battery and ensure you get the best out of it for longer, and in this guide we’ll walk you through what these are.

Why do electric cars lose charge when parked?

Lithium-ion batteries are great at preserving power, but like all batteries, they suffer from vampire drain. Vampire or phantom battery drain is the phenomenon that causes an electric car to lose charge when parked.

This is predominately caused by onboard systems, which are left active even when the car is parked. Some of these are important, such as battery temperature management and protection against theft, but other unnecessary systems can also contribute to phantom drain.

The condition in which a person leaves their electric car parked can also diminish the battery life. For example, ambient temperatures wreak havoc with a lithium-ion battery's ability to store and maintain maximum charge. Therefore, it is advised that an electric car isn't left to sit in direct sunlight for an extended period of time.

Electric car batteries are not fond of colder climates either. The ideal solution is to let your electric car sit inside a garage, where the temperature is moderate and constant.

How much charge can your electric car lose when it’s parked?

This depends on what is causing vampire drain on your battery power and how your electric car is being affected.

If the car is left with only essential systems active, then the loss of charge will be minimal. 

It is suggested that an electric car will only lose around 2-3% of its charge a month whilst parked without being driven. So if you have an EV with a 200-mile range, you would expect to lose approximately 4 to 6 miles over the duration of a month. 

However, the current understanding of electric car batteries suggests they will lose more charge if connected to external apps that keep the car 'awake' even when it is not in use.

How can you prevent your electric car from losing charge while it's parked?

Of course, you'll want to prevent your battery from draining as much as possible when you're not using your car.

Here are our top tips to help you do just that:

Activate energy saving mode

Even though the setting may not be called “Energy Saving” in every model, most electric cars have a feature similar to this. Consider activating this next time you go on holiday or if you are planning to leave your vehicle parked for longer than usual.

Energy Saving or Power Saving mode is designed to minimise energy consumption. This is a key feature among electric vehicles because it preserves battery power by disengaging certain systems which are not necessary while the car is parked. This might include GPS, which, if left active, may download regular updates and lead to a loss of battery power.

Teslas have a special security feature installed called Sentry Mode, whereby the car examines the environment around the vehicle when left unattended. Although a clever feature from a security perspective, it drastically drains the battery. In this case, you might be forced to choose between security and battery preservation.

Deactivate unnecessary pre-set features

Be sure to switch off Wi-Fi, roaming features and your GPS' automatic updates, along with any other pre-set features.

Set it to deep sleep

Putting electric cars into a deep sleep or power save mode will decrease the hold of the dreaded vampire drain by leaving the minimum number of systems active from which power is lost. In deep sleep, the electric car is essentially dependent on 12v battery power, which maintains absolute necessities, such as central locking.

Let your car go into a deep sleep and resist the urge to check on it using the app. Often an electric car owner will want to check in, especially if they have left the car while they’re on holiday. But, every time you open a companion app, it wakes the car up, draining more power.

Ensure your battery is not charged to 100% or lower than 20%

The optimum charge for a standard electric car battery is around 80%.

It is not recommended that you leave your car parked with 100% since the battery may be damaged if the vehicle is left for a prolonged period with this much power stored.

How long can an electric car sit without charging?

Electric cars are modern vehicles; they are designed to be able to sit for weeks at a time without charging. However, exactly how long the car can be left will depend on the make and model, the type of battery and the state the car is left in.

As discussed, activating energy or power-saving mode, enabling your car to sink into a deep sleep and deactivating the vampiric sentry mode will all increase the length of time an electric car can sit without charging.

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Final thoughts

If you are serious about switching to or sticking with electric cars, the best thing you can do to optimise your vehicle's performance is to understand its battery.

You might want to consider having a home EV charger installed so you can charge your electric car at home. It takes a car longer to charge from empty, so installing a charger at home means you can regularly top up your battery charge and save time.

With electric cars increasing in popularity, it has become pretty easy to source a charging station. So even if you leave home without a full charge, a charge point is probably not far away.

If you do plan to leave your electric car inactive for a week or more, ensure it is charged to 80% or thereabouts. Park it somewhere not too warm, but not too cold either, and pop it into an energy-saving mode.

Next time you go to drive it, your car will be glad to see you and ready for new adventures!

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