FireBeetle 2 ESP32-C6 charging LED

Hello Antonis,

It sounds like you're dealing with a charging circuit that isn't behaving as expected when connected to a solar panel. Here are a few things to consider and check:

1. **Solar Panel Voltage:** You mentioned measuring 5V from the solar panel, which is appropriate for a 5V system. Ensure that this voltage is stable and not fluctuating too much, as fluctuations could affect the charging circuit's ability to detect and charge the battery.

2. **Battery Voltage:** The battery voltage of 3.6V suggests it might be near its fully charged state, depending on the type of battery. For example, lithium-ion batteries can reach around 3.6-4.2V when fully charged. If the battery is already close to its full capacity, the charging circuit might not activate until the battery discharges a bit more.

3. **Charging Circuit Activation:** Some charging circuits have a threshold voltage below which they do not initiate charging. This prevents unnecessary cycling of charging circuits when the battery is nearly full or when the solar panel output is fluctuating around the battery voltage.

4. **Charging LED Indicator:** The fact that the charging LED lights up when connected via USB suggests that the charging circuit itself is functional. This points to a potential issue with how the circuit is responding to the solar panel input.

5. **Connections and Wiring:** Double-check all connections between the solar panel, battery, and the charging circuit (including any voltage regulators if present). Ensure there are no loose connections or unintentional shorts that could be affecting the circuit's operation.

6. **Solar Panel Capacity:** Confirm that the solar panel has adequate capacity to charge the battery under the prevailing light conditions. Insufficient sunlight or shading on the panel could limit its output and affect charging.

7. **Circuit Design Considerations:** Review the datasheet or specifications of your charging circuit and ensure it is designed to work with your specific battery type and solar panel configuration.   https://www.heisener.com/

Given these points, here are some specific actions you can take:
- Monitor the battery voltage over time to see if it increases when exposed to consistent sunlight.
- Check if there are any specific activation conditions (like a minimum voltage threshold) for the charging circuit.
- Verify the specifications of your solar panel to ensure it matches the requirements of your charging circuit.

If after checking these aspects you still encounter issues, consulting the manufacturer's documentation or support for your charging circuit might provide further insights specific to your hardware setup.

Looks like the charge is full.

Thanks for the info.

I guess that the current supplied from the solar panel is not enough, will try to measure it tomorrow.

It sounds like you're working with a solar charging circuit and encountering issues with the charging LED not lighting up when the battery is connected to both the solar panel and the charging circuit.

Here are some considerations and troubleshooting steps:

### 1. **Charging Threshold and Conditions**

- **Battery Voltage**: Typically, for a lithium-ion battery charging circuit, the battery voltage should be lower than its fully charged voltage (around 4.2V for a single cell Li-ion) for charging to initiate. If your battery is already at or above its fully charged voltage, the charging circuit might not activate.
 
- **Solar Panel Voltage**: The solar panel voltage (5V in your case) should be sufficient to both power the load and provide excess voltage to charge the battery. Ensure the solar panel voltage is stable and adequate for charging.

### 2. **Charging Circuit Configuration**

- **Connection**: Verify that the solar panel is correctly connected to the VIN (input voltage) of your charging circuit, and the battery is correctly connected to the BAT (battery) terminals.

- **Polarity**: Double-check the polarity of the connections. Incorrect polarity could prevent the charging circuit from functioning properly or could potentially damage the circuit.

### 3. **Charging LED Indication**

- **LED Behavior**: The charging LED typically indicates the status of the charging process:
 - **Charging**: LED may blink or stay on steadily to indicate charging is in progress.
 - **Fully Charged**: LED might turn off or change color to indicate the battery is fully charged.
 - **Fault or No Charge**: LED might not light up at all if there is a fault in the charging circuit, inadequate solar panel voltage, or if the battery is already fully charged.

### 4. **Troubleshooting Steps**

- **Measurements**: Continue measuring the battery voltage periodically. If the battery voltage remains at 3.6V and doesn't increase over time, it suggests that the charging circuit might not be functioning correctly.

- **Load and Solar Panel**: Ensure that the solar panel is capable of providing sufficient current to both power your load and charge the battery. Insufficient current from the solar panel can lead to ineffective charging.

- **Circuitry Check**: Review the datasheet or documentation of your charging circuit to ensure it matches your setup and intended usage (e.g., input voltage range, charging current limits).  https://www.heisener.com/

### Conclusion

If the charging LED only lights up when the board is connected via USB and not when connected to the solar panel and battery, there could be several issues at play, including insufficient solar panel voltage, incorrect circuit connections, or a fault in the charging circuit itself. Double-check all connections, measure voltages accurately, and refer to the documentation for your specific charging circuit to troubleshoot effectively. If issues persist, consulting with the manufacturer's support or community forums for your specific charging circuit might provide further insights.