Back to Smartphones
Home > Smartphones > Samsung Galaxy S21 5G (Exynos)
premium

Samsung Galaxy S21 5G (Exynos) Battery review: Good charge-up efficiency

Reading Time: 5 min read
63
battery
Charging Time
1 day 22h
Battery life
Charging Time
0h48
80% Charging time
Charging Time
1h36
Full charging time

Released in January 2021 at a price that places it in the Premium segment ($600-$799), the Samsung Galaxy S21 5G (Exynos) comes with a triple-camera setup and stereo speakers, among other attractive features. Let’s take a look at how its battery performed in our DXOMARK Battery protocol tests.

Key specifications:

  • Battery capacity: 4000 mAh
  • 25W (charger not included)
  • 6.2-inch, 1080 x 2400, 120 Hz OLED display
  • Exynos 2100 (5 nm) chipset
  • Tested RAM / storage combination: 8 GB + 128 GB

About DXOMARK Battery tests: For scoring and analysis in our smartphone battery reviews, DXOMARK engineers perform a variety of objective tests over a week-long period both indoors and outdoors. This article highlights the most important results of our testing. (See our introductory and how we test articles for more details about our smartphone Battery protocol.)

Test summary

Samsung Galaxy S21 5G (Exynos)
63
battery
51
autonomy
73
charging
75
efficiency

Pros

  • Decent efficiency, especially charge up
  • Supports wireless charging

Cons

  • Despite smaller battery, slower charging speed than competition

The Samsung Galaxy S21 5G (Exynos) smartphone comes with a smaller battery and a slower charger than the two Premium devices used for comparison in this review, the Xiaomi Mi 11 and the Oppo Find X3 Neo. The table below shows the battery capacity, charger, display type and resolution, and processor specifications for the three devices.

 Samsung Galaxy S21 (Exynos)

Xiaomi Mi 11 Oppo Find X3 Neo
Battery capacity (mAh)

4000

4600 4500
Charger

25W

55W 65W
Wireless charging

15W

50W

No

Display type, max Hz

OLED OLED

OLED

Display resolution

1080 x 2400 1440 x 3200

1080 x 2400

Chipset

Exynos 2100 Qualcomm Snapdragon 888 5G

Qualcomm Snapdragon 865 5G

Autonomy (51)

How long a battery charge lasts depends not only on battery capacity, but also other aspects of the phone’s hardware and software. The DXOMARK Battery autonomy score is composed of three performance sub-scores: (1) Stationary, (2) On the go, and (3) Calibrated use cases. Each sub-score comprises the results of a comprehensive range of tests for measuring autonomy in all kinds of real-life scenarios.

Light Usage
65h
Light
Active: 2h30/day
Moderate Usage
46h
Moderate
Active: 4h/day
Intense Usage
29h
Intense
Active: 7h/day

The overall autonomy score for the Exynos version of the Samsung Galaxy S21 5G places it between the Xiaomi Mi 11 (36) and the Oppo Find X3 Neo (60). The Samsung provides relatively good autonomy despite its small 4000 mAh battery, while the Xiaomi struggles with a more power-consuming QHD+ display.

Stationary

Samsung Galaxy S21 5G (Exynos)

54

104

Vivo Y72 5G
Best: Vivo Y72 5G (104)

A robot housed in a Faraday cage performs a set of touch-based user actions during what we call our “typical usage scenario” (TUS) — making calls, video streaming, etc. — 4 hours of active use over the course of a 16-hour period, plus 8 hours of “sleep.” The robot repeats this set of actions every day until the device runs out of power. 

Lasting 51 hours 27 minutes in our TUS tests, the Samsung Galaxy S21 5G (Exynos) lands in the bottom quarter of the DXOMARK database. While it is still ahead of the Xiaomi Mi 11, the Oppo lasts 7 hours 30 minutes longer.

Typical Usage Scenario discharge curves

On the go

Samsung Galaxy S21 5G (Exynos)

54

96

Samsung Galaxy M51
Best: Samsung Galaxy M51 (96)

Using a smartphone on the go takes a toll on autonomy because of extra “hidden” demands, such as the continuous signaling associated with cellphone network selection, for example. DXOMARK Battery experts take the phone outside and perform a precisely defined set of activities while following the same three-hour travel itinerary for each device.

The Samsung device goes head to head with the Oppo Find X3 Neo in all mobility use cases, and both the Samsung and the Oppo perform slightly better than the Xiaomi Mi 11.

Estimated autonomy for on the go use cases (full charge)

Calibrated

Samsung Galaxy S21 5G (Exynos)

52

100

Samsung Galaxy M51
Best: Samsung Galaxy M51 (100)

For this series of tests, the smartphone returns to the Faraday cage and our robots repeatedly perform actions linked to one specific use case (such as gaming, video streaming, etc.) at a time. Starting from an 80% charge, all devices are tested until they have expended at least 5% of their battery power.

While the performance of the Exynos version of the Galaxy S21 5G for gaming and for video and music streaming via 4G was disappointing, the device did a good job for both video streaming via WiFi and video playback. But the Oppo Find X3 Neo had better autonomy in all calibrated use cases.

Estimated autonomy for calibrated use cases (full charge)

Charging (73)

The DXOMARK Battery charging score is composed of two sub-scores, Full charge and Quick boost. Full charge tests assess the reliability of the battery power gauge; measure how long it takes to charge a battery from 0% to 80% capacity and from 80% to 100%; and measure how long and how much power the battery takes to go from an indicated 100% to an actual full charge. With the phone at different charge levels (20%, 40%, 60%, 80%), Quick boost tests measure the amount of charge the battery receives after being plugged in for 5 minutes. 

Wired
Wired
55%
in 30 min
0h48
0 - 80%
1h36
Full charge
Wireless
Wireless
22%
in 30 min
1h49
0 - 80%
2h37
Full charge

The S21 5G (Exynos)’s charging performance is average among all devices tested, but its rivals do better, especially the Oppo Find X3 Neo, one of the top scorers for this attribute to date.

Power consumption and battery level during full charge

Full charge

Samsung Galaxy S21 5G (Exynos)

75

106

OnePlus 9
Best: OnePlus 9 (106)

It takes the Samsung Galaxy S21 5G (Exynos) 48 minutes to go from 0 to an 80% charge, which is good. However, the Xiaomi Mi 11 takes just 30 minutes to achieve the same charge, and the Find X3 Neo takes even less time — only 23 minutes.

Time to full charge

Quick boost

Samsung Galaxy S21 5G (Exynos)

66

108

Oppo Reno6 5G
Best: Oppo Reno6 5G (108)

Users can expect only 2 hours 30 minutes of additional battery life after charging the Samsung Galaxy S21 5G (Exynos) for 5 minutes with 20% power remaining, which is a poor showing when compared to the Oppo Find X3 Neo in particular.

Samsung Galaxy S21 5G (Exynos) Xiaomi Mi 11 Oppo Find X3 Neo
Autonomy boost (hh:mm) 20%2:33 2:52 8:20
40%2:36 3:09 6:26
60%2:05 2:54 5:29
80%2:01 1:51 4:14
Percentage boost 20%7.4 %11.2 %22.1 %
40%7.6 %12.3 %17 %
60%6.1 %11.3 %14.5 %
80%5.9 %7.3 %11.2 %
Energy consumed 20%1458 mWh2674 mWh4712 mWh
40%1487 mWh2945 mWh3637 mWh
60%1192 mWh2709 mWh3103 mWh
80%1148 mWh1735 mWh2399 mWh

Efficiency (75)

Our Efficiency score comprises two sub-scores, Charge up and Discharge. Charge up is the efficiency of a full charge (how much energy is drained from the wall outlet vs the energy capacity of the battery, as well as the efficiency of the charger and its residual consumption). Discharge is how much current the smartphone drains from the battery when in use (the ratio of battery capacity to autonomy). Better autonomy with a smaller battery means better efficiency.

The Samsung Galaxy S21 5G (Exynos) posts an average overall score in our Efficiency testing. Among its rivals, it is far ahead of the Xiaomi (46) but behind the Oppo (87).

Charge up

Samsung Galaxy S21 5G (Exynos)

79

84

OnePlus 9
Best: OnePlus 9 (84)

The Samsung Galaxy S21 5G (Exynos)’s adapter is very efficient and consumes almost nothing (just 11 mW) when the phone is detached. By contrast, however, users should unplug the Samsung’s wireless charger when not in use.

Discharge

Samsung Galaxy S21 5G (Exynos)

73

121

Apple iPhone 13
Best: Apple iPhone 13 (121)

The Samsung device lands between the Xiaomi (46) and the Oppo (85) for discharge efficiency, and despite its relatively small battery capacity (4000 mAh), it offers decent autonomy.

Conclusion

The Samsung Galaxy S21 5G (Exynos) is a well-built device, which is reflected in its decent scores for efficiency. While it lands in the bottom half of our database among all devices tested to date, it is well within the norms for Premium segment devices. The Xiaomi and Oppo smartphones have much better charging times compared to the S21 5G, but the Samsung device’s charging is nonetheless very efficient.

DXOMARK invites our readership (you) to post comments on the articles on this website. Read more about our Comment Policy.