Review: ZeroLemon Galaxy S9 8,000mAh Battery Case

ZeroLemon Galaxy S9 8,000mAh Battery Case











  • There' enough power capacity to potentially charge your S8 to full power about two times
  • The charging speeds are quite fast for a battery case


  • The build quality could be better with frontal protection for the screen
(Last Updated On: July 31, 2018)

A case for a smartphone is supposed to be small and that’s because we want the protection and the seamlessness of a case at the same time. Even when it comes to battery cases, which are cases that have batteries within them that can charge your smartphone while it’s on, are also keen at providing a slim form factor so that the user experience isn’t so different from a regular case. That said, there are always brands that are going to go all out with the purpose of a certain product and that’s basically what ZeroLemon has done.

In this review, we’re going to take a look at this ZeroLemon Galaxy S9 8,000mAh battery case. Where most battery cases try to keep it powerful and slim, this case seems to go all-out with its powering capabilities and we think that definitely holds value.


Power Capacity:

The most important part of this battery case is the power capacity and that’s because it starts with 8,000mAh of power capacity. This much power capacity with a battery case is very uncommon as most cases on the market have about 3,000mAh to 4,000mAh which allows them to maintain a small form factor. First though, let’s see how much of this absurd power capacity for a battery case you’re actually able to use.

3.7 x 8,000 = 29,600 / 5 = 5,920

So the amount of power that you’re actually able to use from this charger is going to be about 6,000mAh. This is 2,000mAh less than what the battery case starts out with, but a conversion of power is prevalent with all types of portable chargers and even so, this much power is still a lot. If you’re not using your S9 while charging it with this battery case, you can very well have about two full charges to the S9, something that not many other cases are able to do as they can either charge an S9 to full power only once or they come close to a full charge.

If you’re using your S9 and charging it at the same time, you can still expect one full charge at least, but two full charges might be out of reach because the S9 is a power demanding device and so it’ll be using up power and gaining it at the same time.

In the power capacity department, this charger battery case rocks, but with so much power there’s an equivalent exchange in design and we’ll get to that in the design section.

Output Charging:

There’s only one method of charging from this battery case and that would be the USB-C portend. The charging rate for the S9 is 5V/1.5A, so it’s definitely not a fast charging speed but at the same time, we’re glad that ZeroLemon didn’t just settle for a 1 Amp plain charging rate. However, for such a high power capacity battery case that’s quite large, we would have like that if they implemented a 2 Amp charging rate.

This battery case does not feature priority charging, meaning that it will not charge your S9 at Quick Charge speeds when you use a Quick Charge wall charger to recharge the battery case. Instead, the battery case will simply charge the Galaxy S9 and recharge from the wall charger.

Input Charging:

To recharge this battery case there’s a USB-C input port on the case and it has a 5V/1.8A charging speed. So to recharge the case as fast as possible we recommend that you use a 2 Amp wall charger or higher. The case does not feature wireless recharging and also, when you have the case on, the S9 is not able to wirelessly charger or conduct NFC.


Size and Weight:

This is where the higher power capacity of the battery case takes effect because the case is quite a lot larger and heavier than your average battery case.

The length of the case is 6.2 inches and the width of it is 3.1 inches, and both of those dimensions basically match other battery cases. The main difference is that this charger has a 0.9-inch thickness and so it’s nearly 1-inch thick. This is something not many people look for in a case and this is basically the price you pay for having such a high power capacity. You’re definitely going to be noticing this case in your pocket and also the bulkiness of it when you hold it in your hand.

The weight of the case is going to add on 7 ounces to the 6 Ounces weight of the S9.

In some cases, depending on what you’re doing on your S9, you might have to hold the case with two hands because of how large it is. With all that said, we can’t really hold the size of the case against it and that’s because it’s part of the integral factor which would be the higher power capacity of the case. So if you’re getting this case for more power capacity to use and know of its larger size and weight, then we say go for it.

Functional Components:

Unlike other battery cases, this ZeroLemson one actually comes apart and does require some assembly. The battery case has a total of three parts:

Battery Portion

Frontal Frame

Soft Case

The first thing to do is to place the S9 into the battery case part where the USB-C connection is, and once that’s done you can then place the frontal case onto the battery portion. After that, you can then place the phone into the Soft Case.

At the back of the case is where you’ll find the power button and four White LED power capacity indicators. To turn on the charger you have to hold down the power button for about 3 seconds and to turn it off you have to do the same thing.

There aren’t exactly cutouts for the buttons for the S9 there are mainly indentations and they do make easy to press the buttons even though the case is quite a thick. The most notable difference is trying to access the fingerprint scanner on the back and that’s because there’s such a large depression and that makes it more difficult to get to the fingerprint scanner.

At the bottom is where you’ll find the USB-C port for recharging the battery case and also a cut-out for the headphone jack.


Structure and Material:

Since this battery case is very thick and large, you would think that protection would be flawless but that’s actually not really the case. From the back to sides of the S9, your phone is going to be safe. However, when it comes to the frontal protection it’s different because the case does not make use of raised bezels and that’s why you should still be careful not to drop this case.

It’s a disappointment that the case doesn’t provide frontal protection for the screen but at the same time, it makes sense as having bezels would make it more difficult to access the edge to edge display on the S9.


On the tech side, this battery case does not get too warm, but if you’re charging you S9 for long duration then it does get a little warm but you won’t really notice because of the top case piece.


On the powering side, this ZeroLemon battery case does a phenomenal job with providing enough power capacity to charge the S9 to its full power about two times, which is basically double than what most other battery cases are able to do. That said, the unreliable part is the user experience when it comes to very large thickness of this charger due to the higher power capacity, so if you’re prepared for it and want a lot more power with a battery case, then this ZeroLmeson battery case can prove to be very reliable.



There’s enough power capacity to charge the S9 to full power about two times, that’s a lot for a battery case.


The thickness of this case is very large and it’s going to be very noticeable once you place it into your pocket and when you hold it.


Even though the case has a great side and back protection it doesn’t have very good or any at all frontal protection for the screen.


Nearly everything for this battery case is reliable, with the power capacity being the main part as there’s so much, but the form factor can cause some trouble if you’re not prepared for it.

Specs of the ZeroLemon Galaxy S9 8,000mAh Battery Case:

  • Power Capacity: 8,000mAh | Output Capacity: 6,000mAh
  • Output: 5V/1.5A
  • Input:

USB-C Input: 5V/1.8A

  • LED Power Indicator: Four White Power Indicators
  • Size: 6.2 x 3.1 x 0.9 inches
  • Weight: 7 Ounces


We commend ZeroLemon for creating an S9 battery case that holds nothing back with its power capacity even if it means having a larger form factor.

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