The Difference Between Series & Parallel Connections

This instructional video provides an in-depth exploration of connecting solar panels in series and parallel configurations, emphasizing the importance of understanding these arrangements for optimal solar energy system design. When panels are connected in series, the total voltage increases while the amperage remains unchanged. For example, connecting two 550W solar panels, each with a voltage of 50V and an amperage of 15A, in series results in a combined voltage of 100V, with the amperage steady at 15A. On the other hand, in a parallel connection, the voltage remains constant, but the amperage accumulates. Using the same panels in parallel maintains the voltage at 50V, but increases the amperage to 30A.

It’s crucial to note that while these configurations alter voltage and amperage, the total wattage output of the panels remains the same. Wattage is a product of voltage and amperage, so whether the panels are in series or parallel, the total power capacity does not change. However, the choice between series and parallel connections should be strategically made based on the input parameters of your solar charge controller (MPPT), solar pump controller or inverter combo. Always read the manual first, plan accordingly and test with a multimeter (on DC setting) before connecting!

Each solar controller or charger has specific voltage and amperage limitations, and it’s essential to configure your solar panels within these parameters. Failing to do so can result in damage to your equipment. For example, a series configuration may be suitable for controllers that can accommodate higher voltages, whereas a parallel setup might be preferable for systems where higher amperage is beneficial, but voltage limits are lower.

In solar panel installations, an advanced approach involves creating “strings” of panels. A string consists of several panels connected in series. This series arrangement within each string leads to a cumulative increase in voltage while maintaining a consistent amperage across the string. For example, a string might comprise four solar panels, each rated at 50V and 15A. When connected in series, the string would collectively produce 200V while maintaining the 15A amperage.

Once these strings are formed, they can then be connected in parallel with other strings that have an identical number of panels, also connected in series. This parallel connection of multiple strings allows for the amalgamation of amperage while keeping the voltage constant across the entire system. Continuing with the previous example, if two such strings are connected in parallel, the combined system would maintain the 200V voltage level, but the amperage would increase to 30A (the sum of amperage from each string).

This method of organizing solar panels into strings and then connecting these strings in parallel offers significant flexibility and optimization in solar panel installations. It allows for a more efficient and customized setup, particularly in balancing the system’s total voltage and amperage to match the specifications and limits of the solar controller or inverter. By adjusting the number of panels per string and the number of strings in parallel, one can effectively manage the electrical characteristics of the solar array to align with the system’s requirements, ensuring both operational efficiency and the safety of the components.

During the tutorial, we also examine open-circuit voltage measurement, achievable with standard entry-level multimeters capable of measuring DC voltage. Outdoor testing is conducted to demonstrate how the voltage varies or remains constant based on the connection type. The key takeaway is the importance of understanding and respecting the operational parameters of your solar energy system’s components to ensure safe, efficient, and effective use of solar technology.