Nothing beats the excitement of unboxing a new smartphone and enjoying its long battery life. However, after about a year, you may notice that the battery doesn’t last as long as it used to. What causes this decline? Let’s debunk some common smartphone battery misconceptions about extending battery life.

1: CHARGING OVERNIGHT HARMS YOUR BATTERY

You might have heard from friends or salespeople that leaving your phone plugged in overnight is bad for the battery. But who wants to wake up at midnight to unplug their phone? This is one of the most popular smartphone battery misconceptions.

Rest easy. Your phone’s battery is designed to handle overnight charging. When you plug your smartphone in at night, the lithium-ion battery charges slowly until it reaches full capacity at and then stops charging.

“It then shuts off,” explains Isidor Buchmann, founder and CEO of Cadex Electronics and creator of the educational website Battery University. “It’s as if it were on the shelf and not connected at all.”

If the charger is functioning properly, it’s impossible to “overcharge” your phone’s battery beyond 4.1 volts. Is it harmful to keep the battery fully charged for extended periods? It depends on your expectations for battery longevity.

“If you want to keep a battery forever, you might call it ‘overcharging,'” says Buchmann. “But for consumer products like smartphones, people don’t prioritize battery life. In two to three years, you’ll likely replace your phone anyway, and the old battery will still have some life left.”

For devices with longer lifespans, like satellites and electric cars, engineers take special measures to extend battery life. Rechargeable batteries in electric cars, for instance, don’t charge to 100 percent or drain to zero.

“They operate in the middle range to minimize stress on the battery over time,” says Buchmann.

So, there’s no need to wake up in the middle of the night to unplug your fully charged phone. The aim of charging your smartphone is to maximize its use before needing to recharge. You want it at 100 percent in the morning to last all or most of the day.

2: LETTING THE BATTERY DRAIN COMPLETELY IS BETTER

One of the common smartphone battery misconceptions is that you should let your phone battery drain completely before recharging. However, it’s better to charge your phone intermittently throughout the day. The ideal range is between 40 and 80 percent.

According to Battery University, “Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last. If possible, avoid full discharges and charge the battery more often between uses.” (DoD refers to how much energy a battery has delivered. In a fully charged battery, DoD is 0 percent; in a 70 percent charged battery, it’s 30 percent).

However, every three months, you should calibrate the battery by letting it run down until the “low battery” warning appears and then recharge it fully.

3: HEAT DOESN'T AFFECT BATTERY LIFE - SMARTPHONE BATTERY MISCONCEPTIONS

Heat is a major threat to battery longevity. Leaving your phone on the dashboard of your car will reduce its capacity over time.

“It’s like a carton of milk,” says Buchmann, who has written extensively on rechargeable batteries. “If it’s not kept cool, it doesn’t last as long. With a lithium-ion battery, it’s corrosion that sets in and deteriorates the battery.”

Excessive heat and a full charge can be particularly harmful if you’re storing a lithium-ion battery for long periods. Battery University conducted tests on lithium-ion batteries stored for a year at different temperatures. A battery stored at 100 percent charge at 40 degrees Celsius (104 degrees Fahrenheit) loses 35 percent of its total capacity over a year. In the same conditions, a battery stored with only a 40 percent charge loses just 15 percent of its capacity after three months.

This is why battery manufacturers store and ship batteries at controlled temperatures and never at full charge. Does this mean you should keep your smartphone in the fridge overnight? No, unless you don’t plan to use it for a year or you like the feel of a cool phone in the morning.

4: TASK KILLERS HELP CONSERVE BATTERY LIFE

Many people think that constantly closing apps or using task killers helps save battery life. However, this isn’t necessarily true. Modern smartphones are designed to manage background apps efficiently. Manually closing apps can actually use more power as the system has to work harder to reopen them when needed. Task killers can interfere with the operating system’s optimization processes, leading to reduced performance and battery life.

5: USING THE PHONE WHILE CHARGING DAMAGES THE BATTERY

Another widespread smartphone battery misconceptions is that using your phone while it’s charging can harm the battery. While using a phone while charging can generate more heat, which isn’t ideal for the battery, occasional use under normal conditions won’t cause significant damage. Today’s smartphones are built to handle such scenarios. However, if you frequently engage in power-intensive activities while charging, it might contribute to overall wear over time due to the additional heat

FAQs

How often should I charge my phone?

Ideally, keep your phone’s battery level between 40-80% and avoid letting it drop below 20% or charging it to 100% frequently.

Can I leave my phone plugged in overnight?

Yes, modern smartphones are designed to stop charging once they reach 100%, so it’s safe to leave them plugged in overnight.

Is it true that my phone's battery will degrade significantly in a year?

Lithium-ion batteries naturally degrade over time, but following best practices can help slow this process and maintain battery health longer.

Should I use task killers to save battery?

No, modern smartphones are designed to manage background apps efficiently, and task killers can actually reduce battery life by disrupting these processes.