Can mixed panel types lead to efficiency losses in solar systems?

Mismatch Effects

When combining different types of solar panels in a single array, the system’s overall efficiency can suffer. This is due to mismatch between the voltage and current characteristics of the various panels. For example, if a string of five high-efficiency panels is connected in series with a single low-efficiency panel, the entire string will be limited by the lower-efficiency panel. This can result in a significant loss of power output.

Partial Shading Effects

Partial shading occurs when some panels in an array are shaded, while others are not. This can create hotspots, leading to reduced panel efficiency and potential damage. In a system with mixed panel types, the effects of partial shading can be exacerbated by mismatch effects. To mitigate these issues, it’s essential to carefully plan and design the array, taking into account the specific characteristics of each panel type.

Charge Controller Sizing Considerations

When sizing a solar charge controller for a mixed-panel array, system designers should consider the maximum power point tracking (MPPT) capability of the controller. A high-quality MPPT controller can help to optimize power output in the presence of mismatch and partial shading effects. However, the controller’s capacity should also be carefully selected to accommodate the system’s peak power output, which may be reduced due to these inefficiencies. A common rule of thumb is to select a controller with an output capacity of 1.25 to 1.5 times the system’s peak power output.