### Understand the alert

The `upsd_ups_battery_charge` alert indicates that the average UPS charge over the last minute has dropped below a predefined threshold. This might be due to a power outage, a UPS malfunction, or a sudden surge in power demands that the UPS can't handle.

### Troubleshoot the alert

1. Check UPS status and connections

Inspect the UPS physical connections, including power cables, communication cables, and any other devices connected to it. Ensure that everything is plugged in correctly and firmly.

2. Check UPS logs and error messages

Review the UPS logs for any error messages or events that might have occurred around the time the alert was triggered. This information could help you pinpoint the cause of the issue. You can find the logs in the Network UPS Tools (NUT) software.

3. Monitor UPS charge level

Keep an eye on the UPS charge level to determine if it's increasing or decreasing. This information can help you understand the overall health of your UPS.

4. Test UPS batteries

Test the UPS batteries to ensure that they are functioning correctly and have enough charge to power your devices during a power outage. Replace any faulty batteries or upgrade to higher-capacity batteries if needed.

5. Check the UPS load

Review the devices connected to the UPS and calculate their total power consumption. Ensure that the UPS is not overloaded and is capable of supporting the power demands of your devices.

6. Restore the power supply

If the UPS charge level remains low, try restoring the power supply to your UPS. This could involve switching to a different power source, fixing any faulty connections, or resolving issues with your local power grid.

7. Prepare for a graceful shutdown

If you can't restore the power supply to this UPS or if the problem persists,prepare your machine for a graceful shutdown to minimize the risk of data loss or hardware damage.

### Useful resources

1. [NUT User Manual](https://networkupstools.org/docs/user-manual.chunked/index.html)
2. [UPS troubleshooting guide](https://www.apc.com/us/en/faqs/FA158852/)