OnePlus 15 evolves a lot and takes a few steps back, but I still love it so much

Gaming and the 7300mAh Battery

Moving on to the OnePlus 15’s strongest point, we find not only the Snapdragon 8 Elite Gen 5 — one of the first smartphones to feature it (OnePlus takes full advantage of it, even though it’s arguably oversized for current mobile needs) — but also an impressive 7300mAh battery.

How did they manage to import such a large battery to Europe without incurring the extra costs that companies like Vivo or Honor struggle with? Simple: OnePlus used “dual-cell” technology. The device contains two 3650mAh cells, which allows it to bypass some regulatory cost thresholds — though, of course, it’s more expensive to produce and optimize.

For this new flagship, OnePlus promises that after four years, the battery capacity will not drop below 80%.

Fast charging is no longer an issue, especially with this dual-cell setup, which also splits the charging process. We still get a total of 120W, but each cell is charged individually at 60W.

This means much faster charging times compared to a single 60W battery (which would overheat) — and, more importantly, significantly lower temperatures than a single-cell battery charged at 120W.

Temperatures, in fact, surprised me both during charging and gaming sessions. There’s also 50W wireless charging, though you’ll need dedicated accessories to reach that full speed.

After several hours of gaming, I managed to achieve over 10 hours of screen-on time, almost hitting 11. OnePlus has done an excellent job optimizing software and making the most of the Snapdragon 8 Elite Gen 5, showing superior efficiency.

Of course, even the previous OnePlus 13 already offered over a full day of use. Is such huge battery life a plus? Definitely — especially for those who travel or work intensively. And as mentioned earlier, it maintains outstanding endurance even during photo and video sessions.

A full charge takes around 39 minutes, which is almost ironic — OnePlus manages to do it in under an hour, while an iPhone, Pixel, or Galaxy, with often half the capacity, still takes longer than an hour.

The technology is mature and safe. If “leading” brands like Apple or Samsung still avoid implementing it, it’s purely out of convenience — to save on R&D and production costs.

Software: Between Innovation and Inspiration

OxygenOS 16 represents a refined evolution of the UI I tested last year, but like Oppo’s ColorOS, it draws increasing inspiration from Apple. You can see it in the new, liquid-glass-style visuals — especially on the lock screen. It even seems to have borrowed a few visual bugs, such as the fingerprint icon occasionally hiding under notifications.

Notifications themselves are somewhat chaotic: when new ones arrive, they often appear beneath older ones from a day or two before, meaning you’ll likely miss 90% of them. There’s still work to be done.

However, several smart and useful features remain. For instance, it’s still the only phone that automatically hides pop-up notification content if it detects an unfamiliar face looking at your screen from behind.

Another great feature is the ability to set the refresh rate for each individual app — for example, running Google Maps at 60Hz to save power, while forcing Instagram to 120Hz. You can also enable automatic resolution switching (something Samsung still requires manual adjustment for), filter background noise during video calls, activate “Zen Mode” to minimize distractions, or use “Outdoor Mode” to boost signal strength.

On this OnePlus 15, there’s also the new programmable side key introduced with the Nord 5. I still use it to mute the phone, but it can also launch the OnePlus AI Translator (even in real-time), Plus Key, flashlight, and more.

The Plus Key, still introduced with OnePlus Nord 5, is designed to interact with the Mind Space feature. By pressing and holding the button, you can send a voice recording to this AI-powered space, which analyzes your speech and creates “memories.” These can interact with your calendar or reminders.

For example, you can say: “Remind me that tomorrow I have an appointment with OnePlus on H.C. Andersen Boulevard in Copenhagen,” and after processing the note, Mind Space will automatically create a reminder and calendar event. Sure, you can do something similar with Gemini, but it’s less immediate and still struggles with third-party apps.

Mind Space also works with images: just tap to send a screenshot to your virtual diary. The content is analyzed, and the phone gives you a summary. Take a screenshot of an event poster, and a reminder will be automatically generated.

You can also ask follow-up questions to Gemini related to those memories — a handy feature, though currently limited to text-based input, making it a bit cumbersome.

Beyond that, there are other even more useful AI tools introduced with the new AI PlayLab app. My favorite is YumSee, which lets you photograph a menu, translate it into your preferred language, and even convert prices into your local currency. For instance, I used it while dining at Prague Airport to convert Czech crowns into Danish kroner and euros.

Another impressive feature is PhotoSpell: look at these two pictures of the same Prague monument. One is gray — the original. The other, edited by PhotoSpell, shows sunlight and shadows so realistically that you wouldn’t know it was modified unless I told you.

The last one, perhaps less interesting, is Party Up, which adds playful, festive effects to group photos.