Asus Zenfone 3S Max ZC521TL Detailed Review – Battery Monster Smartphone

Asus Zenfone 3S Max ZC521TL is a surprise entry from Asus, as they released it without any previous information. The major news about Asus Zenfone 3S Max ZC521TL is its 5000mAh battery. Though there are few decent smartphones available now in the market with the same level of the battery, the arrival one more Asus smartphone with that level adds more choice to the buyers.

Asus Zenfone Max series is meant to be the list of smartphones with more battery life. Asus did a fine job to keep the Zenfone Max series more active with the quick releases. It is not less than four months from the release of Zenfone 3 Max, the predecessor of Zenfone 3S Max ZC521TL. Compared to the previous editions, Asus Zenfone 3S Max ZC521TL is equipped with better specs and features. The design is also improved when compared to the typical Asus mid-level smartphones.

Before we get into the review, Asus Zenfone 3S Max ZC521TL is a fine looking mid-level smartphone with a massive battery. This could be the main point for the buyers who are looking at this smartphone. Here is our hands-on review of Asus Zenfone 3S Max ZC521TL.

Asus Zenfone 3S Max ZC521TL Build Quality

Asus Zenfone 3S Max Design and Build

Asus Zenfone 3S Max ZC521TL came with an all-metal unibody design. On the right side of the device, there is a power button and volume rockers. On the left, there is a hybrid SIM tray to hold 2 SIM cards or 1 SIM card and 1 microSD card. On the top side, 3.5mm audio jack is located to connect the earphone. On the bottom side, the USB port is placed.

Above the display area, we can found the LED notification light, light and proximity sensors, earpiece and front camera. On the bottom of the display, a fingerprint scanner is available which also acts as a home button in addition to the power button.

The capacitive navigation keys are ditched in this phone. Instead, it uses the on-screen control buttons. It has rounded edges and slim bezels. Overall build quality and aesthetics are good. There are two color variants available. They are gold and black.

Asus Zenfone 3S Max Ports


Asus Zenfone 3S Max ZC521TL has a 5.2-inch IPS display and HD 720p screen resolution. It has a 2.5D arc glass over the top of the screen. It has a 450nit brightness which helps to produce clear display. The viewing angles are good except for extreme wide angles, which is usual.

But the only downside of the display is its HD resolution. It affects the pixel density to be lower with 282ppi. But, the screen size is not 5.5-inch which would have made it even worse. The 5.2-inch display helps the HD display to provide satisfactory results.

Asus Zenfone 3S Max Rear Panel

Hardware and Software Performance

Asus Zenfone 3S Max ZC521TL packs MediaTek MT6750 Octa-core processor along with 3GB of RAM. The graphics processor is Mali T860 MP2, which is an above average performer in the mid segment. The 3GB RAM allows more and more multitasking. The CPU is moderate in performance, though it is enough for casual users. The battery optimization may also be a reason to have a moderate level CPU.

The good news is Asus Zenfone 3S Max ZC521TL is running Android 7.0 Nougat on board. It keeps us away from the OS updates for a while. The Zen User Interface 3.0 is also installed which optimizes the Android OS. The Zen UI did not cut too much of the original Android experience. It keeps most of the Android 7.0 Nougat features available and only adds few user interface changes. Asus always maintains the habit of a pre-installing lot of Zen apps as well as third-party apps. Certain Zen apps are actually helpful, but some are not useful for many users.

The fingerprint scanner in changed to the front side in this new model of Zenfone Max series. But there is a downside with this scanner. To unlock the device, you need to wake up the device. It takes an extra second, which is unnecessary in smartphones.

Asus Zenfone 3S Max ZC521TL was tested for gaming performance, new Android 7.0 Nougat features, multitasking, etc. The gaming performance looks good without any negative remarks. The CPU and GPU are easily managing the workload. With the 3GB RAM, the multitasking performance is extraordinary. We never faced any glitch. We have opened 30 plus apps at the same time with all running in the background. The smartphone easily handles the memory and workload.

Asus Zenfone 3S Max Camera


Asus Zenfone 3S Max ZC521TL has a 13MP rear camera with autofocus and dual tone dual-LED flash. This is a popular mid-level smartphone’s camera. The outdoor photos came very well with the camera. In indoor or low light conditions, we need to change the settings properly to get the desired quality.

The 8MP selfie camera is producing great detailed pictures in outdoor and satisfying pictures in low light conditions. Overall, the camera of Asus Zenfone 3S Max ZC521TL meets the mid-level smartphone requirements.


The center of attraction in Asus Zenfone 3S Max ZC521TL is its battery. It has a massive capacity of 5000mAh. In normal condition, it gives two days standby time. On casual use, we get nearly 8-10 hours of battery backup support. The con of the large 5000mAh battery is the lack of fast charging support. But with two days of standby time, it is not affecting us a lot. When compared to other smartphones of this range, this battery life is better than many branded smartphones.

Asus Zenfone 3S Max Software

Connectivity and other Features

Asus Zenfone 3S Max ZC521TL gets all the necessary connectivity features on board. It has VoLTE support with 4G network. The other connectivity features include WiFi, Bluetooth, GPS, FM Radio, microUSB with OTG support. It has dual SIM slots with one for micro SIM and another for Nano SIM.

There is another special feature which is the Power bank function. Asus Zenfone 3S Max ZC521TL itself can act as a power bank and charge other smartphones. Since it has 5000mAh battery, it is a worthy idea. But the OTG cable is not provided with the package. It has to be bought separately if anyone wants to use the power bank function.


The major point for buyers is as said earlier, the 5000mAh battery with a decent mid-level performance. This is not for hardcore smartphone users. For casual users who are looking for long lasting battery life, Asus Zenfone 3S Max ZC521TL is a good choice. Another point is, it contains all the latest trending features for a mid-level smartphone such as fingerprint scanner, Android 7.0 Nougat, etc. On the con side, it lacks fast charging support.

The price details of Asus Zenfone 3S Max ZC521TL is not officially announced. If the price is highly competitive and under the budget segment, Asus Zenfone 3S Max ZC521TL can make a good way for the buyers.

Asus Zenfone 3S Max ZC521TL Detailed Review – Battery Monster Smartphone
7.9 Overall
Robust Battery Decent Design Android 7.0 Nougat
Build Quality8

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