String
It offers a visual and interactive interface that users can draw string routes on the roof layout, monitor electrical values in real time and validate system compatibility before running a simulation.
Purpose of This Page
The main purpose of this page is to define how solar panels are electrically connected within the system. Proper string configuration is critical for maintaining voltage and current values within the operational limits of the inverter. By ensuring correct configurations, you can maximize system efficiency, prevent potential electrical issues, and guarantee safe and reliable operation over time.
This page also acts as a validation layer, helping you identify configuration mistakes early in the design process before installation.
What You Can Do Here
On the String page, you can perform several key actions:
Create electrical strings by selecting and connecting panels directly on the roof layout
Assign each string to a specific MPPT input, allowing better control over energy optimization and inverter performance
Visually map string routing, making it easier to understand how panels are grouped and connected
Monitor critical electrical parameters, including open-circuit voltage (Voc), maximum power voltage (Vmpp), and current values
Receive real-time validation feedback, with warnings for any configuration that exceeds inverter limits or design constraints
Modify existing strings by adding or removing panels as needed
Distribute strings across multiple MPPTs to balance loads and improve system efficiency
Interface Components
Left Panel: PV System Menu
Navigate between PV Panel, Setback, Inverter, and String
Remains visible without losing the current configuration
Center Area: Roof Layout
Displays the roof layout on a satellite map
Shows all placed panels and roof dimensions
Main workspace for drawing strings
While working:
Strings appear in distinct colors
Routing lines connect panels
Connection nodes appear in drawing mode
Right Panel: Inverter and MPPT Management
Displays inverter specifications (MPPT count, AC power, max DC power, and current)
For each MPPT:
View assigned strings
Track total values
See validation status
How It Works
String creation begins by selecting an MPPT input from the right panel and clicking the "+" button next to it. This activates drawing mode, prompting the user to click panels or drag across multiple panels on the roof canvas to build the string. Each panel added to the path becomes part of the same electrical string.
As panels are selected, the system continuously calculates electrical parameters based on the panel specifications and the inverter model:
Voc, Vmpp, and Isc values update in real time
Routed cable length and total panel count are shown instantly
The allowed panel range for the current string is displayed at the bottom of the screen, representing the worst-case scenario for the project area. Connecting strings beyond the operating limits is allowed but not recommended.
Once a string meets all requirements, a validation summary appears confirming that voltage and current values fall within the inverter's operating limits.
Strings that pass all checks are marked with a green indicator.
If any limit is exceeded, a red warning is shown on the MPPT row. Users may still proceed because production calculations will use the maximum values within the valid limit range. Since operational limits represent worst-case thresholds, connecting additional panels beyond these limits remains a user option.
Multiple strings can be created and assigned to different MPPTs. Each string is color-coded on the layout.
String Creation Process (Step by Step)
Step 1: Select an MPPT Input
Open the right panel and locate the inverter's MPPT inputs. Click the "+" button next to the MPPT you want to assign the string to. This creates a new string entry and activates drawing mode. A prompt appears at the bottom of the screen indicating that panels can now be selected on the canvas.
Step 2: Draw the String on the Roof
Click on individual panels on the roof to add them to the string one by one or drag across multiple panels. As each panel is added:
A routing line connects them in sequence
Electrical values in the right panel update instantly
The panel count and estimated cable length are shown alongside the current voltage range
Once all desired panels are selected, press Enter or Esc to save the string.
For C&I projects, panels can also be selected first and then assigned to a string. In this case, the selected panel group is automatically ordered to minimize cable routing distance.
Step 3: Monitor Real-Time Validation
As the string grows, the system continuously checks whether the configuration is valid:
The MPPT row displays the current Isc value
Red warnings flag any limit violations
The allowed panel count range is shown at the bottom of the screen as a reference
Step 4: Complete and Confirm the String
Once the desired panels are selected and all values are within limits, the string is finalized. A validation summary appears showing:
Voc and Vmpp values for minimum and maximum temperature conditions in the project area
Isc value confirmed against inverter limits
A green ‘All checks passed’ confirmation appears when the string is fully valid, while a red signal indicates ‘Needs correction’.
Step 5: Add More Strings if Needed
Repeat the process for additional strings by clicking the "+" on the same or a different MPPT input. Adding multiple strings to the same MPPT creates parallel strings:
Each new string is color-coded differently on the roof layout
The first current value shown next to an MPPT represents the total combined current of all parallel strings connected to it; the value on the right is the MPPT's current limit. If the total exceeds this limit, a warning is displayed on the MPPT row.
Continue until all panels are assigned and the full system configuration is complete
Key Outputs
Electrical validation result per string with pass or warning status
Voc, Vmpp, and Isc values under minimum and maximum temperature conditions
Panel count and routed cable length per string
MPPT-level current totals and string distribution
Color-coded visual representation of all strings on the roof layout
Real-time system compatibility feedback throughout the configuration process
Stringing losses, including losses caused by panels with different radiation exposure within the same string, or by connecting more or fewer panels than the optimal range, are calculated and presented in the loss chart within the proposal
Important Note: Stringing is optional. Any panel not assigned to a string operates independently at its maximum power point as if an optimizer were present, and contributes no stringing loss.
Related Pages
If you encounter any issues, feel free to contact us.
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