Letting your phone battery die before recharging does not extend battery lifespan

You’ve likely heard advice on how to charge your phone to extend the battery’s lifespan. Perhaps you were told to begin charging it once the battery is nearly dead, to stop charging once the battery is full or to charge it for a certain amount of time. VERIFY reader Kathy asked in an email if it’s true that you shorten a battery’s life by charging it before it’s totally drained.

THE QUESTION

Does letting your phone’s battery die before recharging extend the battery’s lifespan?

THE SOURCES

• Apple

• Samsung

• Google

• Battery University, an educational resource run by battery technology company Cadex Electronics

• University of Washington’s Clean Energy Institute

• Batteries Plus

• Osarumen Igbinijesu, senior quality engineer for Batteries Plus

THE ANSWER

No, letting your phone’s battery die before recharging does not extend the battery’s lifespan. This actually decreases your battery’s lifespan. 

WHAT WE FOUND

Lithium-ion batteries are the most common type of battery in portable electronics, including cell phones, says the University of Washington’s Clean Energy Institute. 

These types of batteries wear down when you drain them to 0% before recharging, says Battery University, an educational resource run by battery technology company Cadex Electronics.

“It's actually a common misconception that you should allow your phone battery to completely die before recharging,” a Batteries Plus blog post says. “Modern lithium batteries that are used in phones today will wear out much faster than they should if you constantly drain the battery to 0%, or let it die, before recharging.” 

At the same time, keeping your battery on the charger when it’s at full charge can also wear down the battery’s lifespan, Battery University says. While you should give it a full charge when you first get a new device, Battery University recommends partial charges afterward.

“Ideally, you can keep your lithium battery at 20 to 80% state of charge,” Osarumen Igbinijesu, senior quality engineer for Batteries Plus, told VERIFY in an interview. “That's the best way to preserve the life in the long run.”

Major phone manufacturers recommend similar advice on their battery care pages.

Apple says there’s no need to let your battery drain to 0% before charging it. The company says its phones also limit and slow charging once your iPhone reaches 80% charge to extend the lifespan of your battery.

Samsung recommends unplugging your Samsung Galaxy once it has reached 100% charge to avoid damaging the battery. Additionally, Samsung says the aging of your phone’s battery may “accelerate” if it’s left at 0% for a long period of time. 

Google, like Apple, says there’s no benefit to letting your phone go to 0% before charging it. Newer Google Pixel phones do the same thing Apple phones do where they limit charging when your phone nears 100% charge.

Apple, Samsung and Google all say that excessive heat lowers battery life. Google says that your phone heats up when it’s charging, so you should unplug it once it’s full to keep it from getting too hot.

What about other rechargeable batteries?

Modern electronics commonly use lithium-ion batteries just like phones do. The Environmental Protection Agency (EPA) says you can find lithium-ion batteries in power tools, digital cameras, laptops, children’s toys, e-cigarettes, small and large appliances, tablets and e-readers.

The lithium-ion batteries in these objects work the same way as the batteries in phones.

For example, Consumer Reports says you should avoid charging your laptop battery all the way to 100% or letting it run down to 0%; it says 20% to 80% charge is the ideal charge for prolonging your battery’s lifespan. 

HP says the same thing about its laptops. The average laptop battery lasts about 1,000 charges, HP says, but only ever charging it to 70 to 75% can quadruple your battery’s lifespan. 

However, different kinds of batteries have different rules. In fact, you actually should let nickel-based batteries drain to zero before recharging them, Battery University says. That’s because these types of batteries might “remember” a lower battery capacity if you don’t occasionally let them fully charge from empty to full, the Clean Energy Institute says.

Nickel-based batteries don’t last as long as lithium-ion batteries, and they’re less common in newer devices, so you likely don’t have many devices that use them. However, you can still find them in some camcorders, drills, computers and other small devices, Nanografi Nano Technology, a technology manufacturing company, says.