Here is how the battery works on the Slim X2 Bluetooth Backlit Keyboard, including battery life, charging, and the low-battery indicator.

Battery capacity: 1300mAh.

Low-battery indicator: the power light blinks red when the battery drops below 15 percent. Note that macOS does not show a battery percentage for our keyboards the way it does for an Apple Magic Keyboard, so it may display around 60 percent even when the keyboard is fully charged.

Charging: connect the included USB-C cable to recharge. A full charge takes about 2 to 3 hours, and the indicator light turns green when charging is complete.

Battery life by brightness level, with the backlight on:

• Level 1: about 144 hours
• Level 2: about 81 hours
• Level 3: about 48 hours
• Level 4: about 32 hours
• Level 5: about 24 hours
• Level 6: about 19 hours
• Level 7: about 15 hours
• Level 8: about 13 hours
• Level 9: about 11 hours
• Level 10: about 10 hours

The backlight turns off automatically when the battery falls below 15 percent. Standby time is about 17 days, and with the backlight off the keyboard can run for about 60 days.