(Last Updated On: August 16, 2018)

A battery case can be one of the most useful charging electronics that you can own and the reason for that is because they’re portable chargers that are in the shape of a case. It’s great to own a portable charger and here at Charger Harbor we actually encourage you to get a portable charger for the portable devices that you own because they feature high power capacities and fast charging tech. At the same time, portable chargers are another type of device that you have to have on you and it can be annoying to have to keep track of it.

A battery case just goes on your smartphone and that’s it, just like a normal case it’s on your phone and the best part is that it can charge your phone while it’s on there. In this guide, we’re going to be covering the most useful battery cases for the Galaxy S9. Most of these battery cases are able to charge the S9 to full power and even a little bit more than that.

With the S9 being a flagship with all the latest powerful specs, the one part of it that’s lacking is the battery still being 3,000mAh, just as its predecessors featured. Since that’s the case, burning into the battery quickly is a common problem and can be solved with a battery case as a seamless solution.

Alpatronix Galaxy S9 4,000mAh Battery Case

To start out with, this battery comes from a well-known brand that specializes in battery cases and they’re known as Alpatronix. The case has a 4,000mAh power capacity so there’s enough power to charge the S9 to full power at least once.

For output charging, the case uses a USB-C connector to charge the S9, and it has a 5V/1.8A changing speed and this is the charging speed that you should expect from battery cases now. A plain 1 Amp charging speed for modern smartphones isn’t able to charge your smartphone at a fast enough charging while you’re using it.

To recharge this Alpatronix battery case is quite innovative and that’s something that this brand is known for, as there are two ways to recharge the case. You can either use the USB-C input port to recharge the case at a 5V/1.8A charging speed which is the faster method to recharge it. Or you can place the case on a wireless charging pad or stand, and it will charge the case at a 5V/1.2A charging speed. Also, you can recharge the battery case and sync with computers at the same time with the case on the S9.

With the S9 already being wireless charging compatible and being able to sync with computers without a case, it’s almost as if having the battery case on the S9 is a seamless experience.

Read Review for Alpatronix Galaxy S9 4,000mAh Battery Case

Specs of the Alpatronix Galaxy S9 4,000mAh Battery Case:

• Power Capacity: 4,000mAh | Output Capacity: 2,960mAh
• Output: 5V/1.8A
• Input:

USB-C Input: 5V/1.8A

Wireless Input: 5V/1.2A

• LED Power Indicator: Four White Power Indicators
• Size: 6.2 x 2.8 x 0.6 inches
• Weight: 4.1 Ounces

ZeroLemon Galaxy S9 8,000mAh Battery Case

When it comes to battery cases, brands try to make their battery cases as slim as possible for the best user experience. However, in general, battery cases are going to have larger sizes and thickness no matter what, as they have built-in batteries. So why not go all out with power, well, that’s basically what this ZeroLemon Galaxy S9 battery case has done since it has a whopping 8,000mAh power capacity. This amount of power capacity is basically double than what most battery case for the S9 have and it’s with this power that you can charge the S9 to full power about two times.

No other battery cases for the S9 feature this power and even though it does make the case a lot larger than others, the usage of this power is really amazing and it truly makes it a reliable battery case in terms of how long you’re able to use it.

The output charging for this case is 5V/1.5A. And it’s recharged through a USB-C input port that has a recharge speed of 5V/1.8A. So to recharge the case at its max charging speed, we recommend that you use a 2 Amp wall charger. Also, if you’re wondering just how thick the case is, it does have a 0.9-inch thickness. As a result, you’re still able to place your smartphone in your pocket but it’s going to feel a lot different than most other cases.

Read Review for ZeroLemon Galaxy S9 8,000mAh Battery Case

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

Elebase Galaxy S9 4,700mAh Battery Case

This Elebaes battery case has quite a high power capacity in comparison to more regular types of cases on the market as it has a 4,700mAh power capacity. This is enough power to not only charge the S9 to full power but you’ll also have some leftover power too.

The case makes use of USB-C connector that has a 5V/1.8A charging speed for the S9 and it has the same recharging speed of 5V/1.8A, too. You can recharge the case and connect your S9 to a computer for sharing files at the same time, so you don’t have to take off the case at all.

At the back of the case, there is something that’s slightly different and it would that this case makes use of a single power indicator that changes colors to indicate how much power is left to use. While most battery cases on the market make use of four power indicators, it’s pretty cool to see this type of design as it changes things up and the indicator is part of the power button too, so it has a more minimalistic style.

This case does add some protection for the S9, with the back and siding being safe, there is a raised bezel at the top and bottom which does provide some protection for the screen, However, the screen does not have full protection as there are no raised bezels to the right and left.

Read Review for Elebase Galaxy S9 4,700mAh Battery Case

Specs of the Elebase Galaxy S9 4,700mAh Battery Case:

• Power Capacity: 4,700mAh | Output Capacity: 3,400mAh
• Output: 5V/1.8A

• Input:

USB-C Input: 5V/1.8A

• LED Power Indicator: Four Different Colors
• Size: 6.6 x 3.3 x 0.7 inches
• Weight: 5.2 Ounces
  

  

CASESSARY Galaxy S9 4,500mAh Battery Case

The main difference between this CASESSARY Galaxy S9 battery cases and most other cases on the market is that it has a slim form factor piece to it that makes the user experience with it better. The slim part that we’re talking about is how the case is slim at the top where the fingerprint scanner is. Most battery cases are thick through their entire structure and that makes it more difficult or awkward to reach for the battery case at the back of the phone.

This CASESSARY battery case is slim at the top portion where the fingerprint scanner is and that makes it easier to get to the scanner to use.

On the powering side, it’s what you can expect from most other cases, as this one has a 4,500mAh power capacity that can charge the S9 to its full power about one time.

However, the output and input charging speeds are quite a lot faster than what most other battery cases feature and that’s because this one has a 12.6W output charging speed. This is quite a lot faster than what a battery case usually features. Recharging this case is even better as it has a 15W recharging speed and that’s why we recommend that you use a Quick Charge wall charger to recharge the case at its max charging speed.

Also, this case features Priority fast charging, meaning that if you use a Quick Charge wall charger to recharge it, the S9 will actually fast charge first, which is something that not many battery cases feature.

Read Review for CASESSARY Galaxy S9 4,500 Battery Case

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

Moonmini Galaxy S9 Battery Case

One other battery case that we want to recommend is from MoonMini. The case has a 4,700mAh power capacity that can charge the S9 to full power about one time and still have some power left over. For output and input charging, it has a 5V/1.8A charging speed. Also at the back of the case is where you’ll find a single power indicator that changes color depending on how much power is left to use. Just like the Elebase case that we mentioned earlier.

Specs of the Moonmini Galaxy S9 Battery Case:

• Power Capacity: 4,700mAh
• Output: 5V/1.8A

• Input:

USB-C Input: 5V/1.8A

• LED Power Indicator: Single Power Indicator
• Size: 6 x 2.8 x 0.7 inches
• Weight: 7.2 Ounces