EV batteries make up a significant portion of the cost of the vehicle, it is the single most expensive component in a battery electric vehicle so it is worthwhile for you to take every action possible to make sure that it lasts as long as possible.

Here are some general tips for taking care of the battery in an electric car:

1. Charge the battery regularly: Make sure to charge the battery of your electric car regularly, especially if you are using it frequently. This will help to maintain the battery’s health and extend its lifespan. Manufacturers do typically give guidance about ideal states of charge for batteries for use and for storage, for when you go away on holiday, for example.
2. Avoid overcharging the battery: It is important not to overcharge the battery of your electric car, as this can damage the battery and reduce its lifespan. Follow the manufacturer’s recommendations for charging times and use a quality charger that is designed for use with electric vehicles.
3. Avoid extreme temperatures: Try to avoid exposing the battery of your electric car to extreme temperatures, as this can damage the battery and reduce its performance. If possible, park your car in a covered or sheltered area to protect the battery from extreme heat or cold.
4. Use the battery properly: Make sure to use the battery of your electric car in accordance with the manufacturer’s recommendations. This includes avoiding deep discharges, which can damage the battery, and avoiding frequent, short trips, which can reduce the battery’s lifespan.

Why do EV manufacturers recommend keeping the battery charge between 20% and 80% ?

Lithium-ion batteries, which are commonly used in EVs, have a finite number of charge and discharge cycles and will eventually wear out.

The number of cycles that a lithium-ion battery can undergo before it starts to degrade can range from a few hundred to several thousand, depending on the specific battery chemistry and the charging and discharge patterns.

For example, some lithium-ion battery chemistries, such as lithium cobalt oxide (LCO), may have a relatively low cycle life and may start to degrade after just a few hundred cycles. Other chemistries, such as lithium iron phosphate (LFP), may have a longer cycle life and may be able to withstand several thousand cycles before degrading.

The recommended charge range of 20% to 80% is often referred to as the “sweet spot” for lithium-ion batteries because it allows for the optimal balance between battery performance and lifespan. Keeping the battery charge within this range helps to avoid both deep discharges, which can damage the battery, and overcharging, which can also reduce the battery’s lifespan.

It is worth noting that the optimal charge range for a lithium-ion battery can vary depending on the specific battery chemistry and the specific application. Some battery chemistries may have a higher or lower recommended charge range, and some applications may require a different charge range to optimize performance. It is always a good idea to follow the manufacturer’s recommendations for charging and discharging your EV’s battery.

What is deep discharge and what does it do to a battery?

Deep discharge refers to the process of fully discharging a battery, typically until it reaches a voltage of 0 volts or a very low state of charge. Deep discharging a battery can be harmful to the battery and can significantly reduce its lifespan.

Lithium-ion batteries, are particularly sensitive to deep discharge. This is because lithium-ion batteries rely on a complex chemical reaction to store and release energy, and deep discharging the battery can disrupt this reaction and cause damage to the battery.

Deep discharging a lithium-ion battery can cause a variety of problems, including:

1. Permanent capacity loss: Deep discharging a lithium-ion battery can cause the battery to lose some of its capacity permanently, reducing its ability to store and release energy.
2. Voltage imbalance: Deep discharging a lithium-ion battery can cause a voltage imbalance between the cells in the battery, which can lead to reduced performance and shortened lifespan.
3. Increased risk of failure: Deep discharging a lithium-ion battery can increase the risk of the battery failing prematurely or experiencing other problems, such as reduced charge acceptance or swelling.

For these reasons, it is generally recommended to avoid deep discharging a lithium-ion battery, and to follow the manufacturer’s recommendations for charging and discharging the battery to help extend its lifespan.

What happens to the battery chemistry during deep discharge that causes problems?

During deep discharge, a lithium-ion battery is subjected to a high level of stress, which can cause a variety of problems with the battery chemistry.

When batteries are over charged or suffer deep discharge, certain things happen to the chemistry that results in the problems mentioned before.

Some of the specific changes of battery chemistry during deep discharge include:

1. Depletion of active material: During discharge, the lithium ions in the cathode of a lithium-ion battery are transferred to the anode, where they are stored until the battery is charged again. If the battery is deep discharged, the cathode can become completely depleted of lithium ions, which can cause damage to the cathode material.
2. Formation of solid electrolyte interface (SEI): Deep discharge can cause the formation of a solid electrolyte interface (SEI) on the surface of the cathode, which can reduce the performance of the battery and shorten its lifespan. The SEI is a layer of lithium salts and other impurities that can form on the cathode during discharge, and it can reduce the ability of the battery to charge and discharge.
3. Formation of lithium dendrites: Deep discharge can also cause the formation of lithium dendrites, which are thin, needle-like structures that can grow from the anode into the cathode. These dendrites can short-circuit the battery and cause it to fail.
4. Voltage imbalance: Deep discharge can cause a voltage imbalance between the cells in a lithium-ion battery, which can reduce the battery’s performance and shorten its lifespan.

Overcharging has very similar effects to the battery chemistry.

 All of these issues can significantly reduce the performance and lifespan of a lithium-ion battery, which is why it is generally recommended to avoid deep discharge and to follow the manufacturer’s recommendations for charging and discharging the battery.