One of the biggest fears that many people have when they switch to be an electric car owner is running out of charge. Whilst a petrol or a diesel car can be revived with a can of fuel if it runs out, an electric car must be plugged in to a charge point to recharge the battery which can be tricky depending on location. However, if you go on holiday and leave the car in a long stay car park, are you going to return to find your electric car with no charge at all?
The short answer is no, provided that you had some charge in the car when you left it there.
Most electric vehicles run on lithium ion batteries as they have a high power-to-weight ratio which means that they hold a lot of energy for their weight, which is crucial when being used in an electric vehicle. Lighter batteries mean that they can travel further on a single charge.
The other advantage of lithium ion batteries is that they have a low "self discharge" rate which means that they maintain a full charge over time better than other battery types.
All of this factors in to being able to leave your electric car for an extended period of time.
Whilst lithium ion batteries do lose charge when the car is parked for an extended period, the good news is that this is usually a very minimal amount of the overall charge. Most electric cars can expect to lose only lose a few percent of their charge a month if sitting idle.
Electric cars, like most modern cars, have multiple electronic systems in place to continuously monitor your car whether it's driving or not. As these systems run endlessly in the background to keep the key components operational and running smoothly they are naturally using some of the battery power, with the high voltage battery taking over powering some of these systems from the standard 12v battery.
As is the case whilst driving, temperature can play a factor in the amount of charge that your electric car loses whilst parked too . Extreme temperatures in either direction can cause your car battery power to drain. In cold weather electric cars will continuously warm areas to prevent from getting too cold and causing parts to malfunction.
Conversely, in hot weather a parked electric car will do the opposite and employ the cooling systems, particularly around the battery itself to protect it from long term damage.
If you know that you're going to be leaving your electric car parked for an extended period of time it's worth noting that manufacturers don't recommend charging the battery completely or letting it dwindle before you leave your car parked.
Leaving the battery power too high or too low whilst letting your electric car sit can actually damage the battery cells in the long run. Instead, they recommend anywhere between 50% and 80% charge being ideal. Many electric cars allow you to set how much you would like it to charge when you have your vehicle plugged in, making it easier for you to protect your battery life.
Some cars do have a sleep or power save mode so that the car systems know not to expect to be in use but differ from car to car. The Nissan Leaf recommends keeping the car unplugged from the charging station so that it can enter "deep sleep" whilst others recommend leaving the car plugged in to your home charger so that there is power to battery cooling or heating systems. Your user manual will let you know what is best for your specific car.
Some unnecessary systems can also be turned off within the car whilst it's parked for long periods which will help with energy saving. If your car receives automatic updates you can switch those off or if you usually have it set up to start and heat up before you need to leave that can be switched off too.
Overall, buyers shouldn't be worried if they need to leave their electric car to sit idle or if a change in circumstances means that they reduce their usage drastically. The systems that continue to run in the car will use a minimal amount of the overall charge to keep the car functional but won't drain the charge fully.
Simple things like keeping your vehicle out of direct sunlight, or parking it somewhere covered can help to maintain charge whilst you're not using your electric car. Being aware of what systems are unnecessary and only really need to be on when you're using the car will preserve more of the last charge when parked, but generally you don't need to do anything special if leaving your electric car to sit for any length of time.