Hello AppleGUI,
Many things can occur while in sleep mode with your Mac. Let’s look at some settings and options to help prolong your battery life.
1. Please be aware, when the computer is asleep, power is still used. If you won't be using the computer all night, you may prefer shutting the computer completely down to avoid power being used. Shut down or restart your Mac - Apple Support
2. Also check the tips to extend your battery here: Batteries - Maximizing Performance - Apple
3. Next, please check this help article: Get help with your Mac laptop battery - Apple Support
4. If you are also experiencing heat, please check out this article, as heat is a batteries worst enemy: Keep your Mac laptop within acceptable operating temperatures - Apple Support
"Use your Mac notebook on a stable work surface that allows for good ventilation. Don’t use your Mac notebook in your bed, on a pillow, or under covers."
5. This article will help you check apps and how they are affecting your computer, which can include heat and battery usage: View energy consumption in Activity Monitor on Mac - Apple Support
6. If you still have trouble, an SMC reset may help as it is responsible for power, battery, and charging: Reset the SMC of your Mac - Apple Support
7 . This will help you find the background processes and see what might be syncing in the background. Likely, it's your iCloud data syncing, but there it could be many things: Manage login items and background tasks on Mac
8. Lastly, this is how the testing was done for your Mac model battery, any deviation from these settings, such as screen brightness, is going to use more power and give less time than advertised: MacBook Pro (16-inch, 2021) - Technical Specifications
“Actual rating of 69.6 watt-hours (14-inch model) or 99.6 watt-hours (16-inch model). Testing conducted by Apple in September 2021 using preproduction 14-inch MacBook Pro systems with Apple M1 Pro, 8-core CPU, 14-core GPU, 16GB of RAM, and 512GB SSD; and preproduction 16-inch MacBook Pro systems with Apple M1 Pro, 10-core CPU, 16-core GPU, 16GB of RAM, and 1TB SSD. The wireless web test measures battery life by wirelessly browsing 25 popular websites with display brightness set to 8 clicks from bottom. The Apple TV app movie playback test measures battery life by playing back HD 1080p content with display brightness set to 8 clicks from bottom. Battery life varies by use and configuration. See apple.com/batteries for more information.”
Once you adjust your battery settings, test and see if you get longer life. Cheers.
