Is It Harmful To Leave Your EV Plugged in All the Time?

Leaving an electric vehicle (EV) plugged in all the time is generally not harmful to the battery, but following the manufacturer’s guidelines for charging and storage can help maximize the battery’s lifespan. Most modern EVs have sophisticated battery management systems (BMS) that ensure that the battery is charged optimally and help avoid overcharging or undercharging.

However, there are some factors that can affect the battery’s lifespan if the EV is left plugged in all the time. For example, exposing the battery to extreme temperatures (both hot and cold) for extended periods can degrade the battery’s health over time. Similarly, exposing the battery to high levels of charge (eg charging to 100% capacity frequently) can also impact its overall lifespan.

To minimize impact, follow the manufacturer’s guidelines for charging and storage. Some manufacturers suggest keeping the battery between 20–80% capacity to optimize its lifespan. Additionally, if the EV is going to be stored for an extended period (ie several weeks),leave the battery level at ~50%.

How Do EVs Prevent Their Batteries from Being Overcharged?

A BMS is a crucial component in an EV that manages the battery pack’s performance, safety and health. It’s responsible for monitoring and controlling various aspects of the battery, including its charging and discharging, temperature, voltage, and current.

Like most in the space, VinFast eSUVs have a BMS that regulates the charging process, ensuring the battery is charged optimally. 

Some functions include — 

State of Charge (SOC) Monitoring: The BMS measures the battery’s SOC, which is the percentage of its full capacity that is currently available. This information is used to estimate the remaining range and ensure that the battery is not overcharged.

Temperature Management: The BMS monitors the temperature of the battery and ensures that it stays within an optimal range. If the battery exceeds the optimal temperature, the BMS may reduce the charging rate or activate a cooling system to prevent damage.

Fault Detection and Safety: The BMS detects any faults or abnormalities in the battery pack and takes appropriate action to ensure safety. For example, if the BMS detects a short circuit, it may disconnect the battery from the rest of the vehicle to prevent damage.

If you plan to leave your EV inactive for an extended period, it is generally recommended to keep it plugged in to maintain the battery’s health and avoid excessive battery discharge, also known as vampire drain.

What Is Vampire Drain?

Vampire drain is a phenomenon in which an EV loses its battery charge over time, even when it is not in use. There are several factors that contribute to vampire drain in an EV, including:

Standby power consumption: Even when an EV is off, it still consumes some power to maintain the BMS, remote connectivity and other electronic components.

Temperature control: If the EV’s BMS is set to maintain a certain temperature range, it may consume additional power to heat or cool the battery when the vehicle is not in use.

Security systems: If an EV has security systems (such as an alarm or motion detector), they may consume power even when the vehicle is parked and turned off.

While vampire drain can be a nuisance for EV owners, it is generally not a significant issue for most EVs as standby power consumption is usually quite low.

Should I Leave My EV Plugged in for Long Periods of Inactivity? 

Naturally, EVs are designed to be plugged in for longer periods, so this shouldn’t be much of a worry. One advantage of leaving your EV plugged in is that the battery remains at a stable temperature—even in extreme weather conditions. Batteries perform best when they are kept within a specific temperature range and when you leave them plugged in, they will maintain the temperatures in a good range. Most EVs have a sleep mode option, which reduces the power the vehicle uses when it is not being driven, further reducing the overcharging risk.

If you plan to leave your EV inactive for an extended period—several weeks or months—check the vehicle’s owner’s manual for specific storage recommendations. In some cases, the manufacturer may recommend storing the vehicle with a certain charge level or disconnecting the battery entirely to prevent damage due to long periods of inactivity.

Keeping your EV plugged in during periods of inactivity is generally a good idea to maintain the battery’s health and prevent excessive discharge. However, it is important to follow the manufacturer’s guidelines for battery maintenance and storage to optimize the battery’s lifespan.

What Settings Are Best for Leaving My EV Plugged in Long-Term? 

If you are planning to leave your EV plugged in for an extended period, here’s what you should do:

1. Set a charge limit

Setting a charge limit on your EV controls how much the battery is charged. You can set longer charging periods so it doesn’t overcharge the battery.

2. Maintain a cool environment

Extreme weather conditions can, in the long run, harm your battery. It’s best to store your EV in a cool and dry environment, such as a garage or charging station with a covered area. Keeping the vehicle dry can prevent corrosion and other body damage.

3. Enable storage mode

Most EVs come with a storage mode setting that reduces the battery charge level and optimizes it for long-term storage.

4. Use a trickle charger

A trickle charger is a low-amperage charger that slowly adds charge to the battery over time. It prevents the battery from discharging. Unplug the charger once the battery is charged. Once the battery is fully charged, always unplug it on time to prevent overcharging.

Conclusion 

Keeping your EV plugged in during periods of inactivity is generally a good idea to maintain the battery’s health and prevent excessive discharge. However, it is important to follow the manufacturer’s guidelines for battery maintenance and storage to optimize the battery’s lifespan.