Car Reviews

Will An Electric Car Lose Battery While Parked?

Tesla parked out in the cold snow

Electric cars are an exciting new addition to the world of automobiles, but first-time buyers understandably have a lot of questions. Whether that’s wondering how much it costs to charge or if your electric car will lose battery while parked and powered off.

While everyone understands what to expect from a gas-powered car, electric vehicles (EVs) have a lot of unknowns for newcomers. No one wants to leave an EV parked and return to a dead battery.

And while yes, just like any battery-powered device, your electric car will lose some of its battery power while not in use, it’s insignificant. You won’t return to a stranded vehicle. Plus, how much the battery drains depends on the vehicle’s make, model, and charge level. So, here’s what you need to know.

Table of Contents

What to Know About Your Electric Car Battery
How Much Battery Will My EV Lose While Parked?
Deep Sleep Mode and the 12V Battery
Should I Charge My EV Before Long-Term Storage?

What to Know About Your Electric Car Battery

An EV at a public charging station

Before diving into this topic, I wanted to quickly clear up a few things about the battery. First, not all electric vehicles use the same battery and charging technology, so it’s always best to refer to your owner’s manual. Don’t just Google it. Check your owner’s manual for all sorts of helpful information directly from the manufacturer. The manual will have a specific area regarding long-term storage.

Then, similar to the battery in a smartphone, the lithium-ion battery in your electric car can and will degrade over time. Just like a traditional internal combustion engine (ICE) that loses performance from wear and tear over time.

Furthermore, just like a smartphone or rechargeable AA batteries, your electric car battery will drain slowly while not in use. However, this is extremely minimal, and you could leave your EV battery at 50% and come back six months later and be fine. However, it’s important to note that different temperatures will affect how fast or slow it drains.

More importantly, electric vehicle battery packs don’t degrade nearly as fast as that cheap little battery in your iPhone. Federal regulations require all EV makers offer up to an 8-year or 100,000-mile warranty on the battery. So if one degrades faster than expected, it’ll be under warranty.

How Much Battery Will My EV Lose While Parked?

battery warning dash light

Again, this is a tricky question to answer, considering all the different makes, models, situations, and temperatures. If you don’t use your vehicle for a few days or even weeks, don’t expect a large dip in battery levels. However, if you don’t drive an electric car for six months, it could lose upwards of 10 percent of the battery while sitting.

For example, BMW states that your EV can be nearly dead and only have 6 miles of range left, and owners could leave it for over two weeks and be fine. However, Tesla says to leave the car plugged in for long periods not being used so the battery management system can handle everything.

According to Consumer Reports, the bigger issue isn’t leaving a vehicle parked but battery cells losing power over their lifetime. The site says electric car owners can expect to lose a little over 2 percent of their driving range annually. For example, a Nissan Leaf that gets 149 miles of range will only get around 132 miles after five years of use, recharges, or even while sitting.

If you own a Tesla Model 3, after five years, its 250 miles of driving range could drop to around 221 miles, which is 88% capacity. Thankfully, experts suggest that EV batteries typically last anywhere from 10-20 years. Tesla even promises that after eight years or 150,000 miles, its batteries are still good for at least 70% capacity.

So, just like a gasoline vehicle, electric cars will slowly get less range over time due to wear and tear. As for the original question, your EV will lose a little battery while parked and not in use for long periods, but it’s not enough to be of any concern.

Deep Sleep Mode and the 12V Battery

Battery warning light on dashboard

Depending on how long you plan on leaving an electric car parked and not in use will determine the battery-draining situation. However, the bigger concern is actually the regular 12V battery in every car, not the massive battery packs that propel your EV down the road.

When you drive a regular vehicle, the alternator recharges the 12V battery that handles all the lights, accessories, and the starter. If you leave any car (gas or electric) sitting long enough, the 12V battery will die and need a jump-start.

The massive battery cells under an electric car aren’t a concern when you leave the vehicle parked or unused for an extended time. For example, Nissan says to leave a Leaf EV at around 50% charge, and it’ll automatically go into a “deep sleep” state to preserve everything. But, if you’re not paying attention, the 12V will be dead depending on the model of the car you own.

On the flip side, Tesla instructs owners to plug in their EVs if it isn’t being used for long periods. That way, the battery management system can again keep the battery packs at safe charge levels, prevent over-charging, and maintain optimal 12V battery levels. This ensures owners return to a car that still has juice in all the batteries and is ready to go.

Should I Charge My EV Before Long-Term Storage?

An EV plugged into a charger.

If you plan on not driving an electric car for 30 days or longer, you’ll want to check the battery level. Most manufacturers suggest keeping it above 20% but under a 90% charge. That’s because a battery that’s too low or too full can get damaged over time. As a result, you’ll want to charge your vehicle to an acceptable battery level before going on vacation or extended storage.

While it’s a good idea to follow traditional battery guidelines by keeping it somewhere between 50-70% charged for storage, this varies by manufacturer. KIA, for example, says you can plug it in, leave it unplugged, or do whatever, and it’ll be fine. Personally, I’d still charge my vehicle to 70%, just in case.

Most electric cars have a deep sleep or power-saving mode designed for this exact scenario. It’ll minimalize energy use during long-term parking, let the battery management system and computer keep an eye on everything, and preserve the system (and 12V battery) for you. Some manufacturers say to enable deep sleep and plug it in, while others recommend unplugging it.

See a trend here? How much your EV battery will drain and what steps to take for storage varies by the manufacturer. In closing, ensure the vehicle has at least 50% battery remaining, check your owner’s manual, and follow the manufacturer’s guidelines to avoid a low battery and other potential problems.

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