How to set a custom notification sound for Low Battery alert on MacBook M4 Pro with macOS Tahoe 26.1?

On macOS, the Internal Low Battery alert does not have a user-configurable notification sound, and in many builds of macOS, it is intentionally silent.

Apple does not expose any setting in System Settings → Notifications to change or enable a sound for battery alerts.

System-level battery alerts are handled by the power management subsystem, not the regular Notification Center. 

Use a third-party menu-bar battery monitor

Apps like:

• AlDente Pro
• Battery Monitor
• Endurance
• BetterBattery (SetApp)

Sorry, but... WHY?

If you are using your mac with Three large displays, you are at a desk, for sure.

Just keep it connected to power. It is the recommended and logical thing to do.

Having it deplete the battery before plugging it in is something from the last century.

You are decreasing the life of your battery, probably due to a lingering misunderstanding that may have come from very old days.

+1 to @Luis Sequeira1.

In addition, Here is some of Apple's guidance regarding battery health and management:

Batteries - Maximizing Performance - Apple Support

About battery health management in Mac laptops - Apple Support 

In a nutshell, to get the most from your battery:

• Let the OS and charging circuits manage the charging.

• Plug in when using the computer near available power.

• Use on battery when ac is unavailable or when you must be mobile.

• Don’t allow the battery to regularly discharge deeply before plugging in. Yes, it may happen from time to time, just don't make it a habit.

Luis Sequeira1 wrote:

Sorry, but... WHY?

If you are using your mac with Three large displays, you are at a desk, for sure.

Just keep it connected to power. It is the recommended and logical thing to do.

Having it deplete the battery before plugging it in is something from the last century.

You are decreasing the life of your battery, probably due to a lingering misunderstanding that may have come from very old days.

Echoing this. The best practice is to plug into power whenever it’s convenient and run on battery only when you cannot connect to power. Your Mac uses Optimized Battery Charging, which is enabled by default. That is designed to charge the battery in a way that balances increased battery lifespan with your personal usage patterns. 

About battery health management in Mac notebooks - Apple Support

To confirm that Optimized Battery Charging is enabled, go to System Settings > Battery then click the (i) to the right of Battery Health.

If your Mac is usually plugged in, macOS will pause charging at 80% full since that’s better for the battery long term. If you frequently run on battery, macOS will charge the battery to 100%. That behavior will change depending on your usage.