Is Charging Your Phone All Day Really That Bad? (Published 2020) (2024)

If you’re unsure whether there’s a “right” way to charge your phone — or whether charging it too long, too often or too fast can damage the battery — you’re not alone. I’m a senior staff writer at Wirecutter, and I’ve been writing about phones and tech since 2011. Before that, I was an iPhone sales specialist at an Apple Store. Even with that experience under my belt, it has never been totally clear to me whether being careful about how often I recharge my phone actually extends the life of the battery enough to make a difference, or if it’s just another hassle in a world with far too many of them.

Some people just plug their phones into a charger (or toss them onto a wireless charging pad) whenever power is available. Others fastidiously keep their batteries between 40 percent and 80 percent, never allowing a full charge, guided by the belief that a battery will last longer as a result. Personally, I keep my iPhone on a Qi wireless charger on my desk all day while I’m at work, and I juice it up overnight, as well.

After speaking with battery researchers and the reuse experts at iFixit, reviewing studies on phone replacement trends and analyzing some user data from Wirecutter staffers, we’ve found that although micromanaging your phone’s battery is likely to extend its life to a small degree, the results might not be worth the inconvenience in the long run.

What the science says

Charging your battery causes its performance to degrade over time, no matter how you do it. Smartphones are powered by lithium-ion batteries, which work by moving charge carriers (in this case, lithium ions) from one electrode to another. The ions move in one direction when charging and in the other when discharging.

Moving those ions puts stress on the electrodes and leads to reduced battery life, according to Hans de Vries, senior scientist at Signify (formerly Philips Lighting) and the co-author of the research paper “Increasing the Cycle Life of Lithium Ion Cells by Partial State of Charge Cycling,” which appeared in the journal Microelectronics Reliability.

“The lithium ion needs some space in the electrodes and the electrode has to make this space, and because of the stress,” Mr. de Vries said, “the electrodes will gradually degrade and that is also then a loss of capacity in the battery.”