The LED indicators on the front of the controller show its current status:

1. Single LED blinking rapidly — Pairing mode (searching for a device)
2. Single LED solid — Wirelessly connected
3. Two LEDs solid — Wired connection (USB)
4. All 4 LEDs blinking rapidly — Charging
5. All 4 LEDs off after charging — Fully charged
6. RGB light turns red and blinks slowly — Low battery
7. All LEDs off — Powered off