Charging & LED Indicators
The NanoVNA-F V3 has two indicator LEDs — one red and one blue — located on the top edge of the device. Their behavior communicates the current charging and power state without needing to check the on-screen battery voltage.
LED State Reference
Section titled “LED State Reference”| Device State | RED LED | BLUE LED |
|---|---|---|
| Fully charged (USB connected) | OFF | ON (steady) |
| Normal operation (no USB) | OFF | OFF |
| Low battery warning | OFF | ON (steady) |
| Charging (device off) | ON (steady) | FLASH |
| Charging while operating | FLASH | OFF |
Understanding Each State
Section titled “Understanding Each State”Fully Charged
Section titled “Fully Charged”When the battery is fully charged and the USB cable is still connected, the blue LED remains on steadily and the red LED is off. You can safely disconnect the USB cable or continue operating.
Normal Operation
Section titled “Normal Operation”During normal battery-powered operation (no USB connected), both LEDs are off. Check the on-screen battery voltage display (region 8) for remaining charge.
Low Battery
Section titled “Low Battery”When the battery voltage drops to a low level, the blue LED turns on steadily as a warning. The red LED remains off. Charge the device soon to avoid data loss from unexpected shutdown.
Charging (Device Off)
Section titled “Charging (Device Off)”When the device is powered off and connected to USB for charging, the red LED is on steadily and the blue LED flashes. This is the normal charging indication.
Charging While Operating
Section titled “Charging While Operating”When you continue using the device while it charges over USB, the red LED flashes and the blue LED is off. The device is simultaneously drawing power for operation and charging the battery.
Charging Guidelines
Section titled “Charging Guidelines”| Parameter | Value |
|---|---|
| Charging interface | USB Type-C |
| Charging voltage | 4.7 V to 5.5 V |
| Battery capacity | 4500 mAh (3.7 V lithium-ion) |
| Typical battery life | Up to 5 hours |
| Full charge voltage | Approximately 4.2 V |
| Low battery threshold | Below 3.3 V |
Troubleshooting
Section titled “Troubleshooting”LEDs do not light up at all during charging:
- Verify the USB cable is properly seated in the Type-C port
- Try a different USB cable or power source
- Ensure the power source provides at least 4.7 V
Device will not power on:
- If the battery is deeply discharged, connect USB power and wait several minutes before attempting to power on
- The device can operate while charging if the battery is too low to start on its own
Battery life is shorter than expected:
- Higher brightness settings consume more power — reduce to 60% or 40% for field work
- Continuous sweeping with maximum points (801) uses more power than lower point counts
- Cold temperatures reduce effective battery capacity