Review: CASESSARY Galaxy S9 4,500 Battery Case

CASESSARY Galaxy S9 4,500 Battery Case











  • Enough power capacity for one full recharge
  • The output and input charging speeds are faster than what most other battery cases are able to offer
  • The large cut-out at the back of the battery case makes it easier to access the fingerprint scanner as it's more slim


  • The case does not provide full frontal protection for the S9
(Last Updated On: July 31, 2018)

Something that you likely already know about battery cases is how they’re quite a bit larger than just a regular case, and that’s of course because of the use of batteries and other charging components within the case. Well, the larger form factor of a battery case is basically a given, and so you’re left with making the choice of whether or not you think it’s worth getting a battery case because of its charging cabilities and how easy it is to have a portable charger double as a case.

In this review though, we’re taking a look at this CASESSARY Galaxy S9 4,500mAh battery case that has quite different design in comparison to many other battery cases on the market as there’s a portion of the case that’s actually more flushed in to give the case a slimmer form factor.


Power Capacity:

The most important part of a portable charger is the power capacity, and this case has a 4,500mAh initial power capacity and it’s important to know that the power capacity that the brand specifiesB is simply what the charger starts out with. This is not the power capacity that you’re actually able to use to charge your smartphone with as power is lost during charging. So let’s go over how much of the power capacity you’re actually able to receive from this charger.

3.7 x 4,500 = 16,650 / 5 = 3,330

So the output capacity, the power capacity that you’re actually able to use to charge your Galaxy S9 is about 3,300mAh. This much power is actually perfect for charging the S9 as the smartphone itself has a 3,000mAh battery, and so this CASESSARY battery case is able to charge it to full power at least once. That said, your results for a full charge might vary and that’s because you likely might be using your smartphone and charging it at the same time and so the battery case is going to be charging the S9 but at the same time, the S9 is going to be using power.

So if you want to make the most of the power capacity then it’s best to charge your S9 when you’re not using it.

Output Charging:

The charging speed for most battery cases on the market has gotten faster over time and at this time, the main charging rate is either 5V/1.5A to 5V/1.8A. These are pretty good charging speeds that make up for the higher power consuming smartphones that we use nowadays. At the same time, it’s barely just enough.

This CASESSARY battery case has quite a faster charging speed than what most other battery cases feature as this one has a 12.6W (9V/1.4A) charging speed. The brand states that the battery case is able to charge the S9 at Quick Charge speeds, and even though the charging speed of the case is quite fast, the charging from the case is not Quick Charge because it’s not 18W.

However, if you want to charge your Galaxy S9 at Quick Charge speeds with the case still on, then you can. That’s because this case features Priority fast charging for the S9, which means that you use a Quick Charge wall charger with the USB-C input port on the case and your S9 will fast charge from it. We think that’s what CASESSARY means that this battery case is able to fast charge, and it might explain a few of the negative reviews that this case has gotten.

Input Charging:

To recharge the battery case there’s a USB-C input port and the recharging speed of the case is also a lot faster than most other cases as it has 15W recharging speed. So we recommend that you use a Quick Charge wall charger to recharge the case as its max charging speed.


Size and Weight:

Okay so from the images, the case looks like it has a very slim form factor but really, this battery case is very similar to the many other battery cases on the market and making a small portion of the case slim doesn’t really do much.

So the battery case has a length of 6 inches, a width of 2.8 inches, and a thickness of 0.7 inches. The weight of the case is going to 6.4 Ounces onto to your S9. So a large portion of the case is still quite thick and the slim top part of the case is more shaped like a regular case, but there is a positive to that and that would be the fact that you have easier access to the fingerprint scanner.

Unlike most battery cases that have a large depression at the cut-out for the camera and fingerprint scanner, this one has a much smaller design and therefore your finger can have easier access to the back.

Functional Components:

If you’ve used a battery case before then you know what to expect as the battery case has a power button at the back and there four power capacity indicators. You have to hold the power button for a few seconds to turn on charging and hold it down again to stop charging. At the bottom is where the USB-C port is which allows you to recharge the battery case and have your battery case also charge your S9 at the same time. This is called Pass-Through Charging.

Also, you can sync your S9 with a laptop through the USB-C input on the case and so you don’t even have to remove your S9.


Structure and Material:

The build quality of the battery case features the same amount of safety that most other battery cases feature with it providing protection from the back, and sides and particularly on the front. The frontal protection for the screen isn’t the best because the raised bezels on the case are only at the top and bottom. So if you drop your Galaxy S9 face first then it like won’t be fully protected.


On each side, if you’re pass-through charging from this battery (charging your S9 and recharging the battery case at the same time) then the case will likely get warm.


The battery case features enough power capacity to supply a full charge for the S9 and it has a faster output and input charging speed than most battery cases on the market.



There’s enough power capacity for a full recharge and the charging speed from the case is quite a lot faster than what most other battery cases feature. The highlight feature though is the use of priority fast charging where you use a Quick Charge wall charger with the battery case and recharge your S9 at Quick Charge fast charging speeds.


Even though the small portion of slimness that the battery case has might not be major, it is useful for when it comes to using the fingerprint scanner as it provides better access to it.


On the build side, the case has a good amount of protection at the back and sides, but the front doesn’t have nearly as much protection.


It’s a very reliable battery case for the S9 that accommodates its battery capacity and compatibility with the fast charging tech known as Quick Charge.

Specs of the CASESSARY Galaxy S9 4,500 Battery Case:

  • Power Capacity: 4,500mAh | Output Capacity: 3,330mAh
  • Output: 12.6W (9V/1.4A)
  • Input:

USB-C Input: 15W (9V-1.67A)

  • LED Power Indicator: Four Different Colors
  • Size: 6 x 2.8 x 0.7 inches
  • Weight: 6.4 Ounces


This CASESSARY Galaxy S9 battery case does a lot of things different than other battery cases for the S9 and because of that, it does them right.

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