String Solving
The string solver automatically arranges panels into electrical strings based on your configuration. This is the core automation that saves hours of manual work.
What is String Solving?
String solving is the process of arranging solar panels into electrical strings—series connections of panels that feed into an inverter. The solver determines the optimal path through each panel group, creating strings of your configured length.
Without automation, designers manually draw polylines connecting panels, counting to ensure each string has the correct number of panels. Branch automates this entire process.
How the Solver Works
When you run SOLVE, Branch processes each panel group:
- 1Reads the panel matrix
Each panel group stores a matrix (grid) of panels organized by rows and columns. The solver uses this structure to understand the physical layout.
- 2Applies your string length
The solver divides panels into strings of your configured length (e.g., 12 panels per string).
- 3Generates optimized routing
The algorithm finds efficient paths through the panel matrix, minimizing cable length while creating logical string sequences.
- 4Handles islands
If a panel group has disconnected sections (islands), the solver handles each section appropriately.
- 5Creates string polylines
The solver draws polylines in AutoCAD representing each string, with embedded metadata for circuit designation and panel connections.
Ground Mount vs Rooftop
Branch uses different solving strategies based on your installation type:
Ground Mount (Portrait)
Uses a fast local algorithm optimized for the regular, repetitive layouts typical of ground-mounted arrays. Solves quickly even for thousands of panels.
Rooftop (Landscape)
Uses a more sophisticated algorithm that handles the irregular shapes and obstacles common in rooftop installations.
Set installation type first
Run BRANCHOPTIONS and set the installation type to Ground (Portrait) or Roof (Landscape) before creating panel groups. This ensures Branch uses the correct detection and solving algorithms.
Configuration Options
These settings in BRANCHOPTIONS control how strings are solved and displayed:
| Setting | Description |
|---|---|
| String Length | Number of panels per string (e.g., 12, 14, 16) |
| Number of MPPTs | MPPT inputs on your inverter (e.g., 3, 4) |
| Strings per MPPT | How many strings connect to each MPPT input |
| String Layer | AutoCAD layer for string polylines |
| String Width | Line width for string polylines |
| Tag Height | Text height for string circuit labels |
| Tag Color | Color for unassigned string tags |
String Output
After solving, each string consists of:
- Polyline — The visual representation of the string path through the panels
- Circuit tag — A label showing the circuit designation (e.g., "1/4a" = Inverter 1, String 4, MPPT a)
- Embedded metadata — Information about connected panels, inverter assignment, and cable data (used by CABLEEXPORT)
Tips for Better Results
Balance panels before solving
Use the +/- recommendations on panel group headers and the ADDPANELS command to ensure each group has a panel count divisible by your string length.
Use MULTISTRING for partial control
If you want more control over string paths, use MULTISTRING to select specific panels and create strings manually while still using your configured string length.
Check uneven string warnings
The solver will warn you if it creates uneven strings. Consider adjusting panel counts or using SINGLESTRING for odd-sized groups.