Xiaomi Redmi 15 5G smartphone review – A hot candidate for the runtime throne

With the Xiaomi Redmi 15 5G, the manufacturer is demonstrating that a low price and very long battery life aren't mutually exclusive. And that it's certainly feasible to offer a powerful mobile phone battery in Europe, even though numerous manufacturers have moved away from this in recent months.

The battery life is indeed very impressive and can easily keep going for two or three days of normal use, long movie sessions, or an afternoon playing your favorite game.

The screen is large, quite bright, and doesn't exhibit PWM flickering.

Apart from that, much of the Redmi 15 5G is merely functional. For example, the occasionally creaky, no-frills plastic chassis, or the cameras which offer rather mediocre image quality.

You also have to make do with a few compromises in terms of performance, both when it comes to the processor and the memory. The speakers aren't exactly a sound marvel either, but the phone does, at least, stay quite cool. 

Xiaomi has clearly made strong battery life a focal point with its Redmi 15 5G, and if that's your top priority, you'll find it tough to come across a better smartphone for $200.

By the way, the Redmi 15 5G is, of course, not fireproof – our pictures of an artificial fire are only for show.

At the time of reviewing, the Xiaomi Redmi 15 5G is currently unavailable to purchase on Amazon. 

It's been quite a while since a Redmi phone came from a purely numbered series. With Xiaomi's Redmi 15 5G focusing on its powerful battery, let's now take a look at the compromises you'll have to deal with for a price of around $200.

Xiaomi has chosen a plastic case for its Redmi 15 5G, and it comes in black, reddish titanium gray, and green with a light marbling effect. The chassis doesn't feel particularly high-quality, but it's decent for the price range.

Pressure placed on the rear side is quickly absorbed by the screen's liquid crystal, and twisting it can cause a quiet creaking noise to emit from the smartphone.

Xiaomi boasts its smartphone as having IP64, which means it's well protected against dust and dirt, as well as rain. However, you should definitely not throw the phone into water. And we should add, don't throw it into a fire either. We used an artificial fire for our photos.

Having a 6.9-inch screen means the phone's dimensions are slightly larger than other smartphones in this price range, and the weight is also higher at 224 grams.

You can insert either two SIM cards or one SIM and a microSD card, but the Redmi 15 5G doesn't support eSIM.

The card reader can expand the storage by up to 2 TB and operates at average speeds.

There is currently no Redmi 15 5G entry in the EU's EPREL database. We were also unable to find any data regarding its lifetime CO² equivalent emissions.

One plus is the plastic-free packaging.

Unfortunately, you don't get anything more than Wi-Fi 5 as a fast Wi-Fi standard. This allows for speeds of up to 340 Mbps. However, in our test with the Asus ROG Rapture AXE11000 reference router, these were also repeatedly accompanied by drops below 100 Mbps.

As the name of the test device already indicates, the phone can also connect to 5G mobile networks and offers numerous frequencies, and this means it can usually be used abroad.

Compared to high-end phones, reception was rather mediocre in various samples during our test. In challenging situations, such as narrow alleys, the reception can be patchy, but you can still make calls with other phones.

For the phone app, Xiaomi leans on Google's standard application. It contains all the essential features and is intuitive to use.

While measuring the call quality in a few test calls, we noticed our caller often sounded a bit muffled through the earpiece, but our voice was recorded quite clearly. Background noise should be avoided as much as possible, since it is only filtered out moderately.

The caller was very easy to understand through both the speaker and the hands-free microphone. Our voice was occasionally recorded a bit quietly, so we had to speak up.

Even in studio light, the results can be rather mixed. The test chart appears patchy in places, and the contrast of text against a red background collapses. In addition, the sharpness of details is rather mediocre.

Shots taken at just one lux brightness allow the subject to be just barely recognized, and can hardly be considered usable.

In Europe, Xiaomi doesn't include a charger, but does include a protective case, a charging cable, and a SIM card reader.

The manufacturer is traditionally rather stingy, offering only a 12-month warranty for its smartphones purchased in the EU.

You shouldn't expect too much from the Qualcomm Snapdragon 6s Gen 3. This is a budget smartphone SoC, and that's highlighted in the Redmi 15 5G's performance. While smooth operation is usually possible, running multiple apps simultaneously or performing demanding tasks quickly leaves the phone overwhelmed.

Many similarly priced phones also offer a bit more power.

Graphics performance is decent for this price range. Graphically demanding tasks such as high-resolution rendering aren't the affordable Redmi 15 5G's strengths, but that's probably not to be expected at this price.

Surfing the internet with the Xiaomi Redmi 15 5G is usually a ton of fun, as even larger pages load quite quickly and images are also available quickly when scrolling.

Thanks to the UFS 2.2 standard, you should be able to enjoy fast data transfers and short loading times. However, although the storage appears impressive on paper, the Redmi 15 5G's storage controller doesn't play ball. It significantly slows down the storage, which means you'll still often have to wait.

In our test, the case barely heated up even after extended load, and we measured a maximum of 40.3°C. While this can be a bit higher on hot days, the Redmi 15 5G is generally well-cooled.

The 3DMark stress tests also showed no significant drops in results. This means we can assume that the SoC maintains a constant maximum performance.

Unfortunately, the speaker only produces mono sound that's a bit high-pitched. Although you can listen to pop music, the phone doesn't sound particularly powerful.

Even with movie sound, you quickly miss the punch, but speech is at least quite understandable.

If you wish to connect external speakers or headphones, you can do so via the USB port or wirelessly via Bluetooth. In our tests, both worked without issues.

For wireless audio transmission, the phone supports the most important audio codecs, including some HD audio-capable options such as LDAC and aptX HD.

The Redmi 15 5G's power consumption is normal to moderate for a smartphone in this performance class.

The smartphone can be charged at a maximum of 33 watts, and it can sometimes take more than three hours to fully recharge, due to the large battery.

The generous power storage also has the advantage of allowing the Redmi 15 5G to be used as a power bank because wired reverse charging is possible at up to 18 watts.

Many smartphones have recently been released in Germany, housing smaller batteries, but not the Xiaomi Redmi 15 5G. It boasts a very large 7,000 mAh battery, allowing it to offer long battery life.

Specifically, the phone achieved a runtime of over 21 hours in our Wi-Fi test, which helped it last two or three days without charging. You can watch movies from the internal storage for almost 30 hours, meaning you could watch all the Harry Potter films and the Lord of the Rings Extended Versions back to back without the battery running out.

Even under heavy load, the battery life is excellent: For example, you can play games for over 7 hours before the lights go out.