Unihertz Tank Review - a new contender for the battery autonomy leader title

Battery Tests

Unihertz Tank packs a 22000 mAh Li-Pol battery that, according to the manufacturer, offers 150 hours of call time and 2380 hours of standby time. It arrives with a 66W fast charger - the same one found in the boxes of the Ulefone Armor 17 Pro and the Ulefone Power Armor 18T. All battery tests we run on the devices we review are developed by us and performed with the screen of the device being calibrated to 200 cd/m². Battery-saving features are disabled. The battery of our review unit charged in full for 2 hours and 18 minutes with the provided USB cable and charger. The charging process maintains a relatively steady pace with a minor slowing down after the battery regains 42% of its charge. The battery temperature sets off at 27°C and gradually increases to 42°C in 47 minutes, which coincides with the moment charging starts to slow down a bit. The temperature stays at this level for 3 minutes and begins to decrease slowly, measuring again 27°C in the end. During our intensive browsing test, the battery of our review unit lasted for 53 hours and 48 minutes. This is the third-best result in this test ever. The first place is taken by Oukitel Wp19 with a 21000 mAh battery, Helio G95 chip, 6.78" FHD+ display, and the second place is taken by Oukitel WP15 with a 15600 mAh battery, Dimensity 700 chip, and a 6.517" HD+ display. The discharging process develops steadily from the start until the end with a very slight slowing down at the end. The battery temperature starts at 27°C, reaches 29-30°C in half an hour and remains at this level until the end, fluctuating between 29°C and 30°C. The video test for battery life uses a 1080p video at 30 fps with a ~20Mbps rate is used. Our review unit's score is 55 hours and 42 minutes. The first place is taken by Oukitel WP15 with 63 hours and 4 minutes, followed by Oukitel Wp19 with 61 hours and 18 minutes. The Tank is third. The discharging process is steady from the start until the end with a minor slowing down after the battery drops to 10% of its charge. The battery temperature starts at 27°C and increases to 28°C remaining at this level until the end. The 4K video battery life test uses a 2160p video at 30 fps with a ~55 Mbps rate. In this test, the battery of the Unihertz Tank lasted for 48 hours and 44 minutes. The WP15 did not participate in this test. Hence, the first place is taken by Oukitel WP19 with 53 hours and 8 minutes. The Tank is second in line. The discharging pattern remains the same as the one observed during the 1080p video test. The battery temperature starts at 24°C, reaches 29°C in 2 hours and remains at this level for 23 hours. Afterward, it increases to 30-31°C and remains at this level until the end. For the 3D Graphics/Gaming test, the YEBIS OpenGL ES 3.0 3D Tech Demo is used. Unihertz Tank occupies the first place in this test with a result of 32 hours and 9 minutes. It is followed by the Oukitel WP15 with 30 hours and 26 minutes and by the Oukitel WP19 with 25 hours and 28 minutes. The discharging process develops steadily until the battery drops to 10% of its charge. At that moment, discharging slows down and does so even more after the battery drops to 5% of its charge. The battery temperature starts at 30°C, reaches 36°C in 2 hours, and stays at this level for 2 hours. Then, it drops to 35°C and maintains this level for 11 hours. Afterward, the temperature goes back to 36°C again for 11 hours roughly. Finally, after the 27th hour from the start, the temperature begins decreasing and measures 27°C at the end. The above photos of the Unihertz Tank are taken with a FLIR thermal camera. They clearly show the smartphone is not very hot. The left photo shows the device's temperature during charging. The hottest zone is the area of the SIM card tray on the left frame, with a temperature of 35.3°C. The charger cable at the point of entering the USB port is with a temperature of 35°C - the second hottest part. The second photo depicts the device's temperature during our 3D battery life test. In this case, the hottest part is the middle of the chin with a temperature of 35.3°C.

Battery Settings

The Battery menu is very simplified. It follows the gray background design theme of the Settings menu with no explicit visual distinction between the separate options. It begins with the current battery status followed by Battery Usage data. Below the usage graph, there's also information about which app or service has consumed the most power. Clicking on it, allows you to manage its battery usage by restricting, unrestricted, or optimizing it. Then there's the Battery Saver - a toggle, which is off by default. You can manually switch it on. There's also a toggle for the saver to switch off automatically when the battery is charged above 90%. There's an option to schedule the battery saver as well. The Battery Manager detects apps that are draining the battery significantly and issues a notification with the option for you to restrict those apps.