Does charging mobile phones, laptops and EVs to only 80% extend battery life?

 Does charging mobile phones, laptops and EVs to only 80% extend battery life?

Electronic devices and gadgets such as smartphones, laptops and electric vehicles (EVs) are becoming an integral part of modern life. But the 'lithium-ion battery' at the heart of all these devices has one major drawback, which is the problem of wear and tear over time.

There has been a discussion in the technology world for years: "Don't charge the battery more than 80% and don't let it drop below 20%. " Is this really effective? Today we are discussing this topic.

The 20-80 rule and the science behind it

The simple meaning of this rule is to limit the charge of your device to between 20% and 80%. To understand how lithium-ion batteries work, a 'rubber band' can be taken as an example. When a rubber band is stretched to its limit (100% charge) or left very loose (0% charge), its elasticity gradually loses its elasticity.

Lithium ions move between the cathode and anode in a lithium-ion battery. When the battery approaches 100% charge, the voltage inside it increases rapidly. This high voltage causes chemical stress on the battery's internal chemistry, known as electrolyte oxidation. On the other hand, when the charge drops below 20%, the internal structure of the battery begins to become unstable, which can cause the battery to permanently lose its capacity.

How much does it matter in battery life?

Battery life is measured in 'charge cycles'. A cycle is the use of 100% capacity. If you always charge from 0% to 100%, the battery will start to lose 80% of its capacity after about 300 to 500 full cycles.

But if you go in the 20-80 range, this number of cycles can increase dramatically. For example, a battery that can only last 500 times when fully charged can be charged 1,000 to 1,500 times if it is limited to 80%.

Heat: The main enemy of the battery

A more dangerous factor for the battery than voltage is temperature. When we charge the battery to 100%, it generates more heat.

Therefore, if we leave the phone on charge overnight, the phone continues to 'trickle charge' even after it reaches 100%. This continuously generates heat and can reduce the battery's life.

Now, the world's largest technology companies have acknowledged this problem and have included solutions in their software.

According to Apple's support page, the iPhone 15 and later models include an 80% limit feature. After turning it on, the phone stops charging after it reaches 80%. Earlier models also have 'optimized battery charging'. Which learns the user's sleep and wake-up schedule and charges up to 80% quickly and the remaining 20% ​​slowly.

Similarly, Samsung's One UI has a 'Battery Protection' feature. In this, the phone does not charge more than 80% when selecting 'Maximum' mode.

Google Pixel also has 'Adaptive Charging', which controls the charging speed to reach 100% just before the morning alarm goes off.

Its impact on laptops and EVs

This rule is even more important not only in smartphones, but also in laptops and EVs. Laptop manufacturers like Asus, Dell, and Lenovo have provided 'Battery Health Manager' in their devices. Which limits the charge between 50-80% even when the laptop is always plugged in.

Similarly, the most expensive thing in an EV vehicle is its battery. That is why EV manufacturers recommend charging only 80% for daily use and charging 100% only for long journeys. Leaving the vehicle below 20% for a long time is considered fatal to the health of the battery.

Myths about batteries

Some people still believe that the battery should be charged only after it is completely exhausted. This idea was true for the old 'nickel-cadmium' batteries, but it is completely wrong for the modern 'lithium-ion' ones. Charging a lithium battery a little at a time does no harm, but rather benefits.

Similarly, there is another misconception that swiping to close all the apps on the phone will save battery. Instead, it is better to let the apps remain 'frozen' in the background, because opening an app repeatedly consumes more energy from the processor.

Shouldn't you charge 100%?

In practical terms, being limited to only 80% all the time can be a hassle for some. If you are going out or traveling for a long day, charging 100% will not hurt anything.

The main thing is that charging the battery to 100% and leaving it on the charger for hours or always charging it to 0% is only bad. Charging the battery to 100% once a month helps to 'calibrate' the device's battery sensor, so that the phone shows the correct battery percentage.

Tips to extend battery life

Try to keep the charge between 20 and 80 percent.

Use a normal charger rather than a fast charger whenever possible, as it generates less heat.

Remove the cover when charging your phone to allow heat to escape.

Never charge it under a bed or pillow.

Don't use cheap and low-quality third-party chargers.

Don't leave your phone in direct sunlight or in a hot car.

Go to battery settings and turn on the 'optimized charging' feature.

Don't play heavy games or do video editing while charging.

Update your software regularly, as it often includes new battery management features Methods are included.