As their name implies, electric vehicles (EVs) rely on electric batteries to drive around and run their various systems. Taking care of your EV’s battery is an essential part of its maintenance. How long can you leave your EV plugged in while its battery charges? How much charge should its battery have if you’re going away on vacation? Let’s look at these questions and more.
Do Electric Vehicles Lose Charge When Parked?
All batteries lose charge over time, including those in electric vehicles. This happens even if the battery isn’t in use. For electric vehicle batteries in particular, you need to watch out for vampiric drain and self-discharge.
Vampiric Drain
Outside factors can cause vampiric drain in your EV’s battery. Vampiric drain occurs when stock installations or aftermarket accessories slowly use up an EV’s battery charge. Some examples of these are Tesla’s sentry mode and USB devices. Usually, you’ll only lose a minimal amount of charge from this, but this adds up over time. If your electric vehicle stays parked for long periods of time, vampiric drain will affect how long your electric car can sit before its battery dies.
Self-Discharge
Self-discharge happens passively due to different factors like the battery’s own internal chemical reactions. Lead acid 12V batteries typically found in traditional vehicles often discharge 5% of their charge per month. High-voltage lithium-ion batteries in EV, on the other hand, will discharge between 1-2% of their charge every month. These discharge rates occur under average conditions though. Various factors like outside temperatures can speed up self-discharge rates.
How Long Can an Electric Car Battery Last Without Charging?
Now that you know that EV batteries can lose charge even when turned off and parked, it’s time to look at how long an electric car can sit without charging. After all, allowing your EV’s battery to drop to 0% and leaving it that way for long periods of time can damage the battery, and new ones aren’t cheap. Most electric vehicles left with at least 50% charge can go months without their battery percentage dropping to concerning levels. Some EV batteries might be able to sit comfortably for months at even lower charges depending on the manufacturer.
That being said, EVs also have smaller 12-volt batteries. These batteries handle low-power applications in case the main battery dies. Some EV systems will monitor both batteries and charge the smaller 12-volt battery with the lithium-ion battery’s charge. Still, you might want to attach a trickle charger to this smaller battery if you’re storing your EV for longer periods.
There are a few factors that affect how long an EV battery will last without charging:
State of Charge
SOC refers to your EV’s battery percentage. Most EV lithium-ion batteries best hold their charge between 30-80% SOC. You might be tempted to leave your EV battery at 100% charge when going for vacation or placing it into storage, but allowing the battery to sit at 100% charge for extended periods can lead to cell damage. You can consult your EV’s manual for its optimal storage SOC.
Battery Size
It stands to reason that the more capacity your EV battery has, the more time it’ll take for its charge to fall to 0%. Alternatively, if your EV battery has a smaller than usual capacity, it’ll take a shorter amount of time before it loses all its charge.
Power Modes
EV manufacturers are always looking to improve their vehicles. Some have coded power-saving modes into their EVs to disable unnecessary software and accessories automatically. This cuts down vampiric drain and extends battery life.
Temperature
Believe it or not, temperature plays a crucial role in determining how long your EV can sit parked without charging. If the temperature’s below 40°F or above 80°F, the battery might drain faster. The best temperature for EV batteries is usually between 70 to 80°F. That’s why it’s often best to park your EV indoors if you’re going to leave it parked for a while.
Can You Leave Your EV Plugged In for Long?
It’s generally safe to leave your EV plugged in. Most of the EVs sold today rely on battery management systems (BMSs) to keep their batteries healthy while charging. The BMS tracks the battery’s SOC, keeps it operating within the optimal temperature range, activates cooling systems as necessary, and protects the battery system from short circuits by disconnecting the battery when it notes possible dangers.
However, always check the manufacturer’s guidelines for your particular EV to find out just how long to leave it plugged.
How Long Can You Leave Your EV Parked?
You can leave your EV parked for long periods of time as long as it’s within the manufacturer-recommended SOC range and is away from harsh temperatures and climates. EVs aren’t as susceptible as combustion-engine vehicles since they have fewer fluids sitting in their lines to worry about.
Other components that you should check before getting back on the road with your EV include its tires, brakes, and other necessary fluids. The tires can suffer from flat spots, dry rotting, and pressure loss the longer they sit unused. Brakes can seize if left unused for long periods, and various fluids can wear lines down and leak over time.
And there you have it! That’s what you need to know about keeping your EV’s battery in good condition before long storage. Remember to read your EV owner’s manual if you need to identify its optimal states of charge. Keep your EV in a stable environment, and it should be set for months.
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