Do Electric Car Batteries Drain When Not in Use?

Electric cars are currently the hot topic when it comes to automobiles, especially concerning sky-rocketing fuel prices and global warming. But have you ever noticed your electric car’s battery drained when using it after a particular period?

Does this make you wonder if your electric car battery drains when not in use? A lot of people are curious about this topic.

So, we’ll break down everything you need to know about electric car batteries and how they work. We’ll also share some tips on keeping your battery charged and healthy!

Do Your Electric Vehicle’s Battery Drains When Not in Use?

Assuming you have a lead-acid battery, the answer is no – your car’s battery will not drain when not in use. However, if you have a lithium-ion battery, it will slowly discharge when not being used.

Since most EVs have a lithium-ion battery, so the chances are likely that your car’s battery will drain even when not in use.

Lead-acid batteries don’t discharge when not in use because they’re designed with a chemical reaction that only occurs when there’s a load on the system.

In other words, the battery only produces power when used to power something else. When there’s no load on the system, the chemical reaction stops, and the battery essentially goes into standby mode.

Lithium-ion batteries work differently. They’re designed to continue the chemical reaction even when there’s no load on the system. This is why lithium-ion batteries will slowly discharge when not in use.

However, the discharge is typically very low. You will only notice a drop in a few percent of the total charge over a month. If you start your car only a couple of days later, the battery will likely not have drained at all.

But if you are looking for an exact amount of battery drainage, it is unlikely to define a figure as every different make and model has a different capacity battery along with various features equipped in the car. Therefore, every electric car’s battery drains according to its specifications.

Do Electric Car Batteries Drain When Not in Use
Do Electric Car Batteries Drain When Not in Use

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Factors that Affect an EV’s Battery When Not in Use

As electric vehicles (EVs) become more popular, it’s crucial to understand how to keep their batteries in good condition. After all, the battery is what makes an EV run!

A few factors can affect an EV battery when it’s not being used, such as the Battery Management System (BMS), temperature, and humidity. Let’s take a closer look at each of these factors to understand better how your EV’s battery drains.

Battery Monitoring System

It’s no secret that batteries power electric vehicles (EVs) in the United States. And as with any battery-powered device, it’s essential to keep an eye on the battery’s health. That’s where battery monitoring systems (BMSs) come in.

BMSs help EV owners keep tabs on their battery’s charge level, voltage, and other vital parameters. But what happens when an EV is left unused for extended periods? Does the BMS impact the battery’s health during these times?

The short answer is yes – the BMS can affect the battery even when the EV is not in use. Here’s a closer look at how this works.

When an EV is not being driven, the battery will slowly discharge. This is due to several factors, including self-discharge (a natural process that occurs when all batteries are stored) and parasitic drains from accessories like the alarm system or radio.

The BMS will constantly monitor the battery’s voltage and current levels to ensure it stays within safe limits. If the battery voltage drops below a certain point, the BMS will automatically initiate a charging cycle to bring it back up to an acceptable level.

However, to perform its duties fully and responsibly, the BMS needs power that it drains from your EV’s battery. So while the BMS keeps your overall battery health safe, it also drains a tiny portion of it to stay active.

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Other Components Running on Battery

Though it might seem like a given, it’s important to remember that anything running on your car’s battery will affect how long the battery lasts. This is especially important to remember with electric vehicles (EVs), which rely solely on batteries for power.

If you have any components constantly drawing power from the battery, even when the car is turned off, it will shorten the battery’s lifespan and decrease its overall performance.

The most common culprits of this are usually aftermarket accessories that are hardwired into the car’s electrical system. Things like alarm systems, GPS units, or even phone chargers can sap the battery’s power over time.

If you have any of these kinds of devices installed in your EV, it’s essential to make sure they are disconnected or turned off when the car is not in use.

Another way batteries can be drained while the car is off is if there is a problem with one of the car’s onboard computers.

A faulty computer can draw too much power from the battery, even when the car is turned off, and cause premature aging of the battery. If you suspect one of your car’s computers may be to blame, it’s best to take it to a qualified mechanic or dealership for diagnosis and repair.


Whether the weather gets colder or warmer, most EV owners in New York think about how extreme temperatures affect our electric vehicles (EVs).

It’s important to remember that just like any other battery-powered device, an EV’s battery is affected by cold weather. In fact, extreme temperatures can have a significant impact on an EV battery’s performance.

When it’s cold outside, an EV battery will have more difficulty holding a charge. The chemical reaction that allows the battery to store energy is slowed down in cold weather. As a result, an EV battery will lose power faster in cold weather than in warm weather.

It’s also important to note that extreme temperatures can damage an EV battery. If an EV battery is exposed to too much cold or heat, it can become damaged and lose its ability to hold a charge. For this reason, taking care of your EV battery in extreme weather is essential.


Humidity can also significantly affect EV batteries when not in use. Batteries are sensitive to changes in relative humidity, and high humidity levels can cause the battery to degrade more quickly.

In addition, high humidity can also lead to the formation of condensation on the battery, which can eventually lead to corrosion and other problems.

When storing an EV battery, it is crucial to keep it in a dry, well-ventilated area to minimize the effects of humidity.

Read How Does Cold Weather Affect Electric Car Performance?

Discharge/Recharge Cycles

You might have noticed that your battery doesn’t seem to hold a charge as long as it used to. This is because the battery will become less efficient at storing and releasing energy over time. This deterioration is caused by “discharge/recharge cycles.”

When you discharge your battery (by using it to power your car), the chemical reactions inside the battery cells create electrons that flow through the circuits to provide power.

When you recharge your battery (by plugging it into an external power source), those same chemical reactions cause the electrons to flow back into the battery cells, restoring its charge.

Over time, however, the battery cells wear out and become less and less efficient, struggling to hold the charge and resulting in a gradual loss of power storage capacity.

This loss of capacity is accelerated by discharge/recharge cycles, which stress the battery and cause it to degrade faster.

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How to Prevent EV Battery Discharge During Storage

Electric vehicles are becoming increasingly popular, but one of their challenges is storing batteries when they’re not in use.

If the battery is allowed to discharge too much during storage, it can become damaged and may need to be replaced.

There are a few things that you can do to prevent this from happening:

Prevent EV battery discharge
Prevent EV battery discharge

Avoid Exposure to Extreme Temperatures

When storing your EV battery, avoiding exposure to extreme temperatures is essential. This can cause the battery to discharge, which can shorten its lifespan.

Store your EV battery in a cool, dry place to avoid this. Consider using a climate-controlled storage unit if you live in an area with extreme temperatures. You should also check the battery regularly to ensure it is not exposed to extreme temperatures.

If you need to store your EV battery in an area with extreme temperatures, cover the battery with an insulating material. This will help keep the heat or cold from directly affecting the battery.

Avoid Keeping the Battery at 100% Charge

It’s no secret that electric vehicle (EV) batteries degrade over time. But did you know that storing your EV with a full battery can accelerate this process?

When an EV is stored with a full battery, the battery is in a “constant state of charge” (CSC), which puts unnecessary stress on the battery and can lead to accelerated degradation.

In fact, some studies have shown that keeping an EV battery at 100% charge can shorten its lifespan by up to 50%.

So what’s the best way to store your EV? First, make sure the battery is at least half-charged before putting it into storage. This will help minimize stress on the battery and prevent it from being discharged during storage.

Second, consider using a battery storage system to help maintain the battery’s charge while in storage.

Control the Optimal Battery State of Charge During Long Storage

One of the best ways to properly store them to prevent discharge during storage is to control the optimal battery state of charge (SOC) during long-term storage.

The SOC is the charge percentage in a battery at any given time. For example, a fully charged battery would have a SOC of 100%. A battery that is half discharged would have a SOC of 50%.

Storing a battery at too high or too low of a SOC can lead to accelerated degradation and decreased performance over time. It can also lead to “thermal runaway,” when the battery temperature gets too hot and causes the battery to catch fire.

The ideal SOC for long-term storage is between 20% and 80%. This keeps the battery from being overcharged or discharged, which can damage the battery.

To control the SOC of your EV battery during long-term storage, you’ll need a battery management system. This system will monitor the battery’s SOC and charge or discharge the battery as needed to maintain the optimal SOC.

Read How Long Can You Leave an Electric Car Without Driving it?

Minimize Using Fast Chargers

Most electric vehicles (EVs) in the United States come with a standard (Level 1) 120-volt charger that can fully charge the battery in around six to eight hours.

While this is fine for everyday use, many people opt for a faster 240-volt charger that can do the same job in half the time.

While fast chargers are handy, especially in emergencies, it is not always the best option.

This is because fast chargers can put a lot of strain on your battery, leading to discharge during storage. This is why it is generally recommended that you only use fast chargers when necessary.

If you need to use a fast charger, you can do a few things to minimize the impact on your battery. First, make sure that the charger is appropriately rated for your EV.

Second, charge your EV for shorter periods rather than longer ones so that the strain on the battery remains minimum. And finally, keep an eye on your battery level and stop charging when it reaches 80%.

Final Thoughts

After all that, we can safely conclude that electric car batteries drain when not in use, but the drainage is only a few percent of the total storage over a month. Nevertheless, you can further minimize drainage by following the tips mentioned earlier.

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