Screen resolution, time and brightness
To control the energy consumption better, the first thing is putting the consumption on the screen. It’d better lower the brightness of the screen or set it automatically to reduce the time it needs for turning off from inactivity. You can also reduce the resolution of the display to Full or HD resolution instead of QHD resolution.
These three options can found in the settings by tapping on Brightness/ Automatic brightness, Screen resolution, and Screen timeout.
Disable Always On display option
Regarding the experiments, the Always On display eats up between 6% of battery life on Galaxy S9 and 10%  on Galaxy S9 + at the end of the day. So, although it’s helpful, you’d better turn it off to save the battery life if you are in a long day workout. To do so, head to Settings>Lock screen>Always On display. Once disabled, you will see the battery life improves considerably.
MED energy saving mode
There are options built in the device that let you better control the battery consumption, including MED and MAX, which allows you to quickly set a number of parameters. The MED option gives you the decent savings and lasts the usage a couple of hours without hibernating the important features on your Galaxy S9 & S9+. The ideal configuration is:

• Enable Background network usage
• Deactivate Always On display
• Disable Speed limiter
• Decrease 10% brightness:
• Lower Screen resolution to FHD+

MAX power saving mode
The second one is the maximum power saving mode, which is expected to extend the battery usage to 5 or 6 hours. Although almost of functions will be sacrificed, this mode can extend the device’s autonomy as long as possible. The best settings for the MAX options:

• Disable Background network usage
• Turn Always On display off
• Enable Speed limiter
• Decrease 10% brightness: -10%
• Adjust Screen resolution to HD+

Limit automatic connections
The Galaxy S9 & S9+ comes with an option to activate the Wi-Fi connection when your phone is in the area of a known network. It’s a pretty convenient feature, but that also means more battery power will be eaten up comparing to turning the Wi-Fi on and off manually. The easiest way to turn this option off is searching it by name in settings and note “Turn on Wi-Fi automatically” option.
Also read: Where And How To Buy Samsung Galaxy S9
Sleep apps
Some applications will consume a lot of battery even when they’re in the background. Fortunately, the Galaxy S9 and S9+ let you know which apps are consuming the most battery. Simply close the process in the background to stop eating up the battery.
Restrict use of data
One of the things that you might not consider is that more battery power will be consumed when apps are connected to the internet through your 4G data in the background. In the information for each app, there’s a section that allows limiting the dât usage for each app.
Monitor app consumption
If you still want to get a deeper control in your app’s power consumption, the Galaxy S9 & S9+ offers two additional options for you. The first as well as the quickest way is heading to the settings and tapping on the battery section. Under the saving modes, you will see the apps that are consuming more battery power of your device.
Choose the apps you want to close and tap on the solution button.  Under the list of apps to close, you can see two more sections: unsupervised apps and always inactive apps. Take a look and put apps in each section.
The second one is navigating to Settings > Applications and adjust the battery power consumption in the apps list. It also includes the application in the optimized app list.
These are popular solutions to save the battery power on Samsung Galaxy S9 & S9 +. If you know other tricks to save battery on the S9 or S9+, let’s know in the comment.