It’s not your imagination: Phone battery life is getting worse

Phone makers promise “all-day battery life.” Sure, and you haven’t stolen any of the kids’ Halloween candy.

If you recently bought a new flagship phone, chances are its battery life is actually worse than an older model.

For the last few weeks, I’ve been performing the same battery test over and over again on 13 phones. With a few notable exceptions, this year’s top models underperformed last year’s. The new iPhone XS died 21 minutes earlier than last year’s iPhone X. Google’s Pixel 3 lasted nearly an hour and a half less than its Pixel 2.

Phone makers tout all sorts of tricks to boost battery life, including more-efficient processors, low-power modes and artificial intelligence to manage app drain. Yet my results, and tests by other reviewers I spoke with, reveal an open secret in the industry: The lithium-ion batteries in smartphones are hitting an inflection point where they simply can’t keep up.

“Batteries improve at a very slow pace, about 5 percent per year,” says Nadim Maluf, the CEO of a Silicon Valley firm called Qnovo that helps optimize batteries. “But phone power consumption is growing up faster than 5 percent.”

Blame it on the demands of high-resolution screens, more complicated apps and, most of all, our seeming inability to put the darn phone down. Lithium-ion batteries, for all their rechargeable wonder, also have some physical limitations, including capacity that declines over time – and the risk of explosion if they’re damaged or improperly disposed.

And the phone power situation is likely about to get worse. New ultrafast wireless technology called 5G, coming to the U.S. neighborhoods soon, will make even greater demands on our beleaguered batteries.

My test has limitations. Your experience will depend on how you use your phone, and there are steps you can take to make your phone life stretch.

We’re not without hope. Two phones that performed well in my tests, Samsung’s Note9 and Apple’s iPhone XR, offer ideas about how to design phones to last longer – at least until a totally new battery tech comes along.

My results made me do a double take, so I called up a squad of other tech journalists also obsessed with testing at CNET, Tom’s Guide and Consumer Reports. “Our overall aver- age battery life is coming down,” says Mark Spoonauer, the editor in chief of Tom’s Guide, who also found the iPhone XS battery died sooner than the iPhone X. Many of the phones with the longest battery life, he adds, are a year old.

But not all other reviewers have noticed the same declines – and the differences in our results help shed some light on what’s going on.

Larger phones often last longer, but it’s not as simple as the size of the battery inside. Remember the Blackberry? Those had much smaller batteries than today’s smartphones, but could go days without being charged.

There’s no perfect battery test. Mine, which I borrowed from an industry group called the Embedded Microprocessor Benchmark Consortium, particularly stresses the screen.

I use a light meter to set all the phones at the same brightness and then force their web browsers to reload and scroll through a series of sites I serve through a local WiFi network. I rerun the tests as many times as possible, and then average the results.

CNET, which like me found conspicuous dips in battery life between the iPhone 8 and iPhone X (and Samsung’s Galaxy S8 and S9), tests screens at 50 percent brightness playing a looping video with Airplane Mode turned on.

What we both discovered: Phones with fancy screens that are especially high-resolution or use tech such as OLED perform worse. (That tech can require more power to push out light.) So if you want your phone to last longer, turn down the screen’s brightness. Or stop looking at your phone so many times each day, if you can break our nationwide spell of phone addiction.

Tom’s Guide throws another factor into the mix: The cellular connection. It makes phones run through a series of websites streamed over LTE. Unlike me, it also saw a big battery life hit to the Pixel 3 XL versus the Pixel 2 XL.

Another lesson: If you want the battery to last longer, use WiFi when possible – or even Airplane Mode when you don’t need to be reachable. Both Apple and Android phones also offer low-power modes (not reflected in our testing) that reduce some draining data functions without taking you offline.

The counterexample is Consumer Reports, which found the new iPhone XS lasted 25 percent longer than last year’s iPhone X. Its test uses a finger robot – yes, you read that right

– to make phones cycle through lots of different functions and apps, including pauses in use where the screen turns off.