The Vivo X300 FE (review) may be a compact offering, but it arrives with a sizeable 6,500mAh battery. Priced in India from Rs 79,999, the handset goes up directly against the OnePlus 15, which now starts at Rs 77,999 following its recent price hike. In our full review, the Vivo X300 FE edged past the OnePlus smartphone in the camera department, delivering punchier colours, better dynamic range, and a wider selection of shooting modes and filters.
But how does it fare on battery life? Can the Vivo X300 FE, with its 6.31-inch display and 6,500mAh battery, outperform the OnePlus 15 (review), which pairs a larger 6.78-inch display with an even bigger 7,300mAh cell? We break it down for you in this comparison. Read on.
Battery specs at a glance
| Smartphone | Battery | Charging speeds |
| Vivo X300 FE | 6,500mAh silicon-carbon | 90W FlashCharge, 40W wireless FlashCharge |
| OnePlus 15 | 7,300mAh silicon-carbon | 120W SuperVooc, 50W AirVooc |
Both smartphones ship with a compatible wired charger in the box and a USB Type A to Type C charging cable.
Table of Contents
Charging speeds
Before we get to the endurance, let’s take a look at how much time it takes the Vivo X300 FE and OnePlus 15 to recharge their respective batteries.
- Vivo X300 FE: Our internal testing showed the Vivo X300 FE taking 41 minutes to charge from 20 percent to a full 100 percent using the ‘High speed’ charging mode. This mode pushes the device to its maximum charging capability, albeit at the cost of higher thermals. The regular charging mode, which the smartphone defaults to, takes around an hour and a half for a full top-up, which is still respectable for a battery of this size.
- OnePlus 15: Contrary to Vivo, the OnePlus smartphone takes just 30 minutes to juice up from 20 percent to 100 percent with its ‘Smart rapid charging’ tech. Charging the device at normal speed can take approximately an hour.
Both smartphones also support bypass charging, allowing users to power the devices directly without significantly stressing the battery while charging, and reverse wired charging. However, that 30W advantage on the OnePlus 15’s charging speeds puts it in the driver’s seat, making it an appealing buy for users who are always on the go.
How about the backup? To find out, we put the smartphone through a series of tests and usage.
Synthetic benchmark battery test
For this, we used the PCMark battery test with both smartphones fully charged and their display brightness and volume levels set at 80 and 50 percent respectively.
The Vivo X300 FE scored 16 hours and 4 minutes in the test, which is commendable, but not quite as impressive as the OnePlus 15. The latter achieved a runtime of 17 hours and 6 minutes in the same test, which automates a series of tasks on the device. That said, when it comes to real-world usage, the difference between the two phones isn’t as dramatic.
YouTube video streaming test
Both phones were used to stream a 60-minute video on YouTube under similar circumstances and network settings. To properly gauge their performance, the Vivo X300 FE and the OnePlus 15 were also set at 50 percent screen brightness and volume levels.
| Smartphone | Display | Peak Brightness |
| vivo X300 FE | 6.31 inches - AMOLED | 5000 nits |
| OnePlus 15 | 6.78 inches - LTPO AMOLED | 3600 nits |
This resulted in the Vivo smartphone’s battery dropping by 3 percent, whereas the OnePlus 15 recorded a 5 percent drop. This suggests that the X300 FE is better optimised for video streaming, despite featuring the same power-efficient LTPO panel as the OnePlus smartphone. While the OnePlus 15 is equipped with a 165Hz refresh-rate display, it delivers 120Hz across system UI and apps (except for gaming).
Gaming test
To test battery efficiency under demanding workloads, we played games on both devices. Once again, the handsets were kept on identical settings, including in-game graphics and frame rates. The titles chosen for testing were the popular BGMI and Call of Duty: Mobile.
| Smartphone | BGMI (Ultra HDR + HDR) | COD: Mobile (Max+Max) |
| Vivo X300 FE | 5 percent | 6 percent |
| OnePlus 15 | 6 percent | 5 percent |
The battery drain figures were recorded after playing each game for 30 minutes on both smartphones. Overall, the handsets delivered similar battery efficiency, with each consuming a total of 11 percent charge.
Regular usage
Speaking of overall endurance in everyday usage, draining the batteries on either smartphone is no easy task. Vivo and OnePlus have done a commendable job with battery optimisation, allowing both devices to comfortably last a full day. The Vivo X300 FE delivers around six hours of screen-on time with mixed usage, which is more than sufficient unless you are constantly on your phone throughout the day.
The handset is capable of lasting up to a day and a half on a single charge with browsing, social media scrolling, streaming, and other casual usage. The OnePlus 15 goes a step further under similar conditions, offering close to two days of battery life. During testing, the smartphone had around 40–50 percent battery remaining after an hour of streaming and gaming, along with regular day-to-day usage.
Verdict
The OnePlus 15 emerges as the more capable battery performer in this comparison, pulling ahead with faster charging and stronger results in both synthetic benchmarks and day-to-day usage. That said, the Vivo X300 FE is far from outclassed. Despite its more compact form factor and smaller battery, it delivers consistent efficiency across video streaming and everyday tasks. In fact, the X300 FE matches the OnePlus 15 in the gaming test, underlining its well-balanced optimisation.
So, should you buy the Vivo X300 FE or the OnePlus 15? It depends,
| Vivo X300 FE | It delivers the best endurance for a smartphone of its size. This makes it an easy recommendation for users looking for a compact smartphone without compromising on battery life. |
| OnePlus 15 | But if the size doesn’t bother you and you want the absolute, the OnePlus 15 is worth considering. |
