Battery life is a perennial gripe for smartphone users. While screen resolution, processing power and design have all raced ahead, battery technology has failed to keep pace. Even Apple isn't immune: Battery life on the iPhone 6s is the same as it was on the original iPhone, launched almost a decade ago.

Now one U.S. smartphone startup wants to solve the problem with software.

San Francisco-based Nextbit, which launched the Robin smartphone earlier this year, is promoting the device as an American-designed product with a heavily tweaked version of Android that dynamically adjusts storage and “makes running out of space history.”

Now the company wants to make the $299 smartphone even better, promising to push out a software update to all users in the final quarter of 2016 that will offer “substantial gains” in battery life. “We are building out the building blocks for a more truly smart operating system,” said Mike Chan, a Nextbit co-founder, who previously helped develop the original version of Google's Android.

Nextbit is not yet promising a specific percentage improvement over current usage, saying it needs to collect more data before giving out those details, but it did say that just like its smart storage solution, its new battery-saving technology will rely heavily on machine learning.

The technology will learn the user's habits and change the background processes where necessary. That means some users will see a bigger benefit than others — depending on how they use their phone — but Chan says everyone will see a big gain.

Because Nextbit controls the hardware as well as the software, it is able to make deeper changes that would not necessarily be possible for other manufacturers. This is not a feature which could be easily ported to a Samsung or Huawei smartphone, Chan says.

While Google has made substantial improvements to its battery-saving features, such as Doze, and manufacturers have introduced impressive fast-charging solutions, Chan says that what Nextbit is doing will take battery saving to “the next level.” “Our approach is very unique and we haven’t seen anyone tackle it in the way we have done,” he says.

The company decided to address the battery issue after it consulted with its community of users. “Battery was by far the area for us to address; it was No. 1 by a landslide,” Tom Moss, another Nextbit co-founder and  former head of business development for Android, told IBT.

Nextbit Robin Hands-On The Nextbit Robin is a design-centric smartphone with a cloud-based version of Android on board. Photo: David Gilbert

Indeed, Moss says it is important for the company's developers to treat users as they would want to be treated themselves, which is why the Robin has received monthly software updates since it launched and will continue to do so. Nextbit says it has no plans to monetize these software updates at the moment, but believes the current smartphone business model where manufacturers push out new devices every few months is just not sustainable.

“You are seeing devices are having a shorter shelf life, especially for top-tier [manufacturers], and we think in the long term that is a bad situation for everybody,” Moss said.