Understand the charging cycle of a battery used in a mobile, laptop or EV in an easy way

 Understand the charging cycle of a battery used in a mobile, laptop or EV in an easy way

'Charging cycle' is an important concept in the context of lithium-ion batteries used in modern devices such as mobile phones, laptops and electric vehicles (EVs). It is directly related to the life and performance of the battery.

A charging cycle is the process of charging a rechargeable battery and discharging it into a load. It is not a unit of time. In simple terms, using 100 percent of the total capacity of the battery is a charge cycle. This does not mean that you have to charge the battery from 100% to 0%.

For example, if you use 75% of the battery capacity one day and fully charge it overnight. And then use 25% the next day, the total capacity consumed by adding these two days is 100%. This is considered one charge cycle.

The number of charging cycles indicates the expected life or lifespan of the battery. If your phone has a charging cycle of 1600, it means that its battery can be safely used for up to 1600 cycles. Since 100 percent charge of the battery is considered one cycle, a total of 160,000 percent charge is achieved in 1600 times.

If you consume an average of 50 percent of the battery per day, your battery life is about 9 years (3,200 days). Similarly, if you consume an average of 80 percent of the battery per day, the battery of that phone can safely last for five and a half years.

How are charging cycles calculated?

Coulomb counting is used to estimate the 'state-of-charge' (SoC) of lithium-ion batteries. This method determines the total charge transfer by integrating the current flowing from the outside to the inside and from the inside to the outside of the battery. Coulomb counting provides a more reliable and real-time assessment than traditional voltage-based measurement methods. Because voltage can often be inaccurate due to temperature and load variations. Battery Management System (BMS) plays a crucial role in monitoring and predicting the condition of the battery for safe use and long life.

Important tips to extend battery life

Protection from high voltage: Charging the battery at high voltage puts stress on the battery. Lithium-ion batteries charge at 4.20 volts per cell. However, charging at a voltage higher than this can have negative effects.

Control excessive temperature: Excessive temperature adversely affects the performance and lifespan of the battery. Avoid overheating while charging or using the battery. Charging the smartphone under a pillow or under a duvet reduces ventilation (air passage) and the battery can heat up and deteriorate faster.

Protection from Parasitic Load: Using the device while charging (called 'parasitic load') can confuse the charger and cause 'mini-cycling', which can increase the stress on the battery. Therefore, it is generally better to turn off the device while charging.

Slow charging is better than fast: Generally, charging a battery at a slower rate is considered better for long-term durability. Fast charging can heat up the device, although modern charging systems are designed to minimize heat generation.

Don't overcharge: Lithium-ion batteries cannot be overcharged. The charge flow should stop once they are fully charged. Continuous 'trickle charging' can lead to plating of metallic lithium, which can affect safety.

Don't fully discharge: It is not advisable to fully discharge lithium-ion batteries. Instead, make it a habit to charge them until the battery is no more than 20 percent full.