Causes for Low Solar Charging Power or Longer Charging Time:

1. Suboptimal Charging Conditions: If part of the solar panel is obstructed, it may cause low charging power or prevent charging altogether.
2. Incorrect Connection of Series/Parallel Panels: If the panels are incorrectly connected in series or parallel, this can cause inefficient charging or low power output.
3. Damage from Drops or Heavy Pressure: If the solar panel is dropped or subjected to heavy pressure, the cells may crack, leading to reduced output power.
4. Degradation Over Time: Over the years, solar panels naturally lose some of their efficiency and power output.
5. Fault in Internal Charging Circuit: While rare, a fault in the internal MPPT charging circuit can result in lower charging power.

Troubleshooting Steps:

1. Check Solar Charging Conditions: Ensure that the solar panel is receiving adequate sunlight without any obstructions.
2. Inspect the Solar Panel Connections: Verify that the solar panels are connected correctly. Incorrect connections may result in insufficient charging power.
3. Assess the Condition of the Solar Panel: Check the panel for any visible damage or issues with performance.
4. Consider Power Degradation Over Time: For older panels, be aware that their power output may have degraded over the years (this applies to panels used for several years).
5. Check for Internal MPPT Charging Circuit Issues: If the above steps don't resolve the issue, the internal charging circuit might need attention (after-sales service).

Remarks:

Factors Affecting Solar Charging Conditions:

1. Light Intensity
2. Angle of Exposure
3. Ambient Temperature
4. Air Quality

Improper Usage Impact:

1. Partial Obstruction: Ensure that the panel is not partially shaded.
2. Cracked Solar Cells: Drops or impacts may cause cracks in the solar cells, which are not always visible to the naked eye and may require specialized equipment for detection.