Single-day battery life has been the norm for far too long. The OnePlus 15 proves we can do better.
Almost every aspect of Android phones today is superior to phones from just a few years ago. Such is the nature of a highly competitive industry like smartphones. Thanks to technological advancements, smartphones today have better displays, faster processors, more intelligent software, and even larger batteries than before. Yet, despite these continued improvements, one aspect has remained frustratingly stagnant: battery life. Most smartphones still last only a single day on a full charge — if even that.
In recent years, we’ve seen battery technology improve and capacities increase, but these advancements were always offset by manufacturers coupling them with bigger, brighter, faster-refreshing displays and increasingly power-hungry system-on-chips. The rise of computationally intensive generative AI features has only exacerbated the issue. Many people accept this trade-off so long as their phones simply survive a heavy day of use, as if it’s a given that we simply have to charge our smartphones every night.
But something significant has happened in the latter half of 2025. A new crop of Android phones, utilizing ultra high-density silicon-carbon batteries, is challenging this norm. We’re seeing a new wave of smartphones with batteries that exceed 7,000mAh, and the new OnePlus 15 is one of the few bringing this breakthrough to North America.
I’ve been using the OnePlus 15 for the past two weeks, and I believe it’s a sign that we’re entering a new era in smartphone battery life: the two-day phone.
Mishaal Rahman / Android Authority
OnePlus 15 and the rise of the two-day smartphone Before the OnePlus 15, I settled on expecting my smartphones to only last me one full day. While I didn’t exactly have day-to-day battery anxiety with my previous phones, the Xiaomi 15 Ultra, the Samsung Galaxy Z Fold 7, and the Samsung Galaxy S25 Ultra, I knew that if I ever needed to push any of these devices to their limits throughout the day, I would likely be reaching for a charger before the day’s end. Only the OnePlus 15’s predecessor, the OnePlus 13, was reliable enough to get me through a heavy day of use no matter what, but even that device couldn’t carry me through a second day without a quick top-up.
In terms of raw numbers, the 7,300 mAh battery in the OnePlus 15 might not seem like a dramatic leap over the 6,000 mAh battery in the OnePlus 13. However, you have to consider that the OnePlus 13 already boasts one of the largest batteries in the North American flagship market — besting the Google Pixel 10 Pro XL with its 5,200mAh battery, the Samsung Galaxy S25 Ultra with its 5,000mAh battery, and the iPhone 17 Pro Max with its 5,088mAh battery. In that context, the OnePlus 15’s battery becomes all the more impressive.
We’re entering a new era in smartphone battery life thanks to phones like the OnePlus 15.
It pushes the device past the threshold of “great single-day battery” into “multi-day battery.” Other recent flagships I’ve used comfortably lasted me a full day but couldn’t reliably get me through an entire second day. Even the OnePlus 13 could only last me well into a second day, but the OnePlus 15 gives enough breathing room to last through it.
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