My Battery Keeps Going Down Fast

This is an Apple article Save energy on your Mac - Apple Support

And other websites

https://www.howtogeek.com/764654/how-to-keep-your-macbook-battery-healthy-and-extend-its-life/

https://www.macworld.com/article/671184/how-to-save-macbook-battery-life.html

https://www.cnet.com/tech/computing/10-simple-ways-to-improve-your-macbooks-battery-life/

Also don’t download any software that “saves” battery. It will do much more harm than good.

Greetings ProfessorAsa,

Thanks for clearing that up for us. Learn some tips to manage your battery life below:

"Manage your Mac laptop’s battery

Your Mac laptop has a battery so you can use it when an electrical outlet isn’t available. To learn how to charge the battery and maintain battery life, see the topics below. To learn if the battery can be replaced, refer to the documentation that came with your Mac.

• Charge your battery by connecting the power adapter to your Mac, then plugging it into an electrical outlet.
• See About your Mac laptop’s power adapter.
• Check your battery’s status. The Battery Status menu at the right side of the menu bar shows you how much charge your battery has and whether it’s currently charging. 
• See Monitor your Mac laptop’s battery.
• Conserve your battery’s power by adjusting options in Battery settings.
• See Change Battery settings on a Mac laptop and Save energy on your Mac." Manage your Mac laptop’s battery

Also, learn how to check your cycle count in order to make sure your battery is healthy: Determine battery cycle count for Mac laptops

We hope this helps to extend your run time.

Best wishes.

Hello ProfessorAsa,

Welcome to Apple Support Communities! We're here to help.

We understand that you're concerned about the battery life on your iPhone and we're happy to provide some information regarding the battery life for the iPhones. 

Below is an article that will provide information about the iPhone battery.

iPhone Battery and Performance

Here is an article that will provide you with suggestions to maximize the battery life of your iPhone.

Maximizing Battery Life and Lifespan

We also want to provide you with an article that will be helpful about the battery usage on your phone.

About the battery usage on your iPhone, iPad, and iPod touch

Here is an article about the iOS performance on your iPhone: About iOS performance on your iPhone, iPad, or iPod touch

We also want share an article about Low Power Mode: Use Low Power Mode to save battery life on your iPhone

Let us know if you have any questions.

Thank you for using Apple Support Communities.

Take care!

Glad this helped! Also check the remaining battery form the Activity Monitor because it is more accurate. Activity Monitor > Power in the center on the bottom.

Have a nice day!

Good afternoon ProfessorAsa,

Happy to hear these recommendations have helped.

Enjoy the rest of your day!