The familiar iPhone warning: The science of batteries relies on ancient chemistry that has already been optimized.

CC BY: Tom Raftery

very few months, cell phones get faster processors, higher-resolution displays, and are infused with powerful new software. Indeed, these pocket computers are now more powerful than the hardware NASA used to send a man to the moon. So why is it, then, that the industry can't seem to make a lasting, reliable battery? Unless they're charged every eight hours, these $500 devices are worth little more than paperweights. Here, a guide to why cell phone batteries still underperform:

Why haven't batteries improved?
"The trouble with batteries, as everyone who makes phones will tell you, is that they don't follow Moore's Law," which posits that computing power will double every two years, says Farhad Manjoo at PandoDaily. That's because batteries depend on "ancient chemistry" that has already been optimized. New improvements "are mainly the result of power-saving techniques in the processors and operating systems that power our devices," not innovations in the battery itself.

How dissatisfied are customers?
Very. In a 2012 survey of 7,080 smartphone owners, research firm J.D. Power and Associates found that, while most users were happy with their mobile devices, battery life was named as "one of the few attributes that have declined greatly from previous years." Manufacturers have dramatically expanded these phones' lists of functions, but we barely have time, within one charge, to use them, says Matt Brian at The Next Web. Consumers are right, says MG Siegler at Parislemon. "I want a laptop that lasts for weeks on one charge. I want a cell phone that lasts a month." These aren't unreasonable demands.

Are new devices making things better?
They might actually be making things worse. Apple's new iPad, for instance, uses a super-fast 4G connection to allow battery-draining activities like face-to-face video chat, says Siegler. Faster, souped-up phones are battery killers, and Apple might even elect not to include 4G LTE on its next iPhone, says John Gruber at Daring Fireball. "It's only going to fly if Apple can figure out a way to maintain current (or better) battery life."

What's the solution?
No one knows. But whoever can solve the battery problem first will see "enormous gains," says Manjoo, "whether it's an incumbent phone maker or Ph.D.-laden start-up in a garage." Battery life is the final hurdle to the mobile digital future we've been promised.

Sources: Daring Fireball, The Next Web, PandoDaily, Parislemon