Super Multi Box – Smart DC Combiner with PV String Fault Discriminator
Patent-pending string fault discrimination to ensure system availability in ground-mounted PV systems up to 1,500 V DC.
No more complete system failures due to insulation faults.
Applications of the Super Multi Box (Smart DC Combiner)
The Super Multi Box is an intelligent DC combiner for PV systems up to 1,500 V DC. It is suitable for PV projects with high availability and monitoring requirements, as well as for demanding projects where multiple strings need to be combined, monitored, and selectively disconnected if necessary.
It is used particularly when multiple PV strings are routed to a central inverter – often with only one MPPT – and a single insulation or string fault must not lead to a complete system shutdown.
Ground-mounted systems, Agri-PV, and PV power plants in the MW range
Central inverter architectures – ideal for 1-MPPT systems
Selective fault isolation and string shutdown to ensure system availability
Patent-pending PV String Fault Discriminator
– Selective fault isolation with system
The patent-pending PV String Fault Discriminator is the central functional element of the Super Multi Box. It enables the selective detection and isolation of individual faulty PV strings within a DC combiner, thereby preventing a complete system shutdown in the event of insulation or string faults in central inverter architectures.
PV String Fault Discriminator
Individual string current measurement
Firefighter Switch
Plug & Play
Monitoring
Combiner for up to 24 strings
Universal communication
Remote maintenance
Surge protection T1+2
Technical background: Central inverters and insulation faults
In conventional DC combiner solutions, an insulation fault, arc fault, or string fault often causes all connected PV strings to be shut down together, as differentiated fault assignment at the string level is not possible. Particularly in central inverter architectures with only one MPPT, this leads to a complete standstill of the affected generator field – even though usually only a single string is actually faulty.
The Super Multi Box takes a different approach: it utilizes a central master logic in combination with the patented PV String Fault Discriminator to specifically identify faulty strings, shut them down selectively, and maintain the operation of the remaining generator fields.
The process in the event of an insulation fault
If an insulation fault occurs in a string, the inverter first detects an impermissible insulation state and initially shuts down the generator.
The Master Super Multi Box receives this error message and automatically initiates a structured identification process:
The result: No more complete system failures due to insulation faults
The Super Multi Box DC combiner works differently. Thanks to the patent-pending PV String Fault Discriminator, a fault does not lead to a blanket shutdown of the generator, but is instead systematically identified. Following the inverter’s fault message, the connected SMB units are automatically switched on sequentially, the fault-causing string is clearly localized and selectively isolated. The remaining part of the system continues to operate.
Conventional DC Combiner vs. Super Multi Box
In conventional DC combiner solutions, an insulation fault often leads to the shutdown of an entire generator section. Particularly in central inverter architectures with only one MPPT, this means: the inverter detects an impermissible insulation state and shuts down the affected generator section – even though usually only a single PV string is affected.
The consequence:
■ Complete standstill of a generator field
■ Manual, time-consuming troubleshooting in the field
■ Unnecessary yield losses
“Insulation faults are not uncommon in ground-mounted systems.
The new Q3 technology saves us days of troubleshooting – and thus hard cash!”
The Super Multi Box DC combiner works differently. Thanks to the patented PV String Fault Discriminator, a fault no longer leads to a blanket shutdown of all PV strings, but is instead systematically identified. Following the inverter’s fault message, the connected SMB units are automatically switched on sequentially, the fault-causing string is clearly localized and selectively isolated. The remaining PV strings or generator fields remain available and system operation is maintained.
OPEX advantage for operators
Particularly in ground-mounted systems in the MW range, insulation faults occur regularly due to moisture, animal bites, cable aging, connector problems, or mechanical stress. While conventional combiner solutions can lead to prolonged downtime, the Super Multi Box reduces:
Especially for utility-scale systems and central inverter architectures with one MPPT, the investment in intelligent DC combiner technology often pays for itself through a single avoided prolonged standstill. It is not the purchase price that counts – but the permanently secured system availability.
✔ Higher system availability
Selective fault isolation prevents the complete standstill of a generator field.
Only the actually faulty string is disconnected – the rest of the DC network continues to operate.
✔ Reduced OPEX costs
Automated identification replaces time-consuming manual troubleshooting in the field.
Fewer service calls, lower personnel costs, shorter fault duration.
✔ Faster ROI
In MW ground-mounted systems, even a single avoided prolonged standstill can compensate for the additional investment compared to a standard DC combiner.
Technical design of the Super Multi Box (DC Combiner up to 1,500 V)
Intelligent DC combiner up to 1,500 V DC – modular and customizable configuration
The Super Multi Box is designed as an intelligent DC combiner for photovoltaic systems up to 1,500 V DC. It combines multiple PV strings into one inverter input and extends the conventional combiner function with selective fault isolation, individual string monitoring, and communication interfaces.
Depending on project requirements, the following features are possible:
Smart DC Combiner for Central Inverters and Utility-Scale PV
The Super Multi Box combines multiple PV strings into a central inverter and extends conventional DC combiners with:
■ Selective string fault isolation
■ Individual string current measurement
■ Communication interfaces
■ Integrated firefighter switch
■ Intelligent monitoring functions
Ideal for:
■ Ground-mounted systems
■ Agri-PV
■ PV power plants in the MW range
■ Central inverters with 1 MPPT
Monitoring, Communication, and Remote Maintenance
The Super Multi Box is not just a DC combiner, but a communication-capable system for monitoring and optimizing the operation of PV generator fields. The combination of individual string current measurement, communication interfaces, and integrated logic provides a transparent overview of the status of the entire DC network.
The Super Multi Box combines selective fault isolation, individual string monitoring, and communication interfaces in an intelligent DC combiner system for utility-scale PV systems.
GUI | Web Dashboard & String Monitoring
Optional web-based monitoring dashboard for visualizing:
■ Individual string currents
■ Status messages
■ Event logs
■ Fault states
The display is clearly organized at the string level and enables rapid identification of deviations.
Modbus RS485
Standardized Modbus RTU interface (RS485) for integration into:
■ PV inverters
■ Data loggers
■ SCADA systems
■ Higher-level monitoring platforms
Enables the structured transfer of measurement and status data.
Ethernet
Network-based communication for:
■ Direct integration into IP structures
■ Remote access
■ Integration into central operational management systems
■ Surge protection (SPD) status monitoring
■ Monitoring the status of optionally integrated SPD modules.
Status messages can be integrated into the monitoring system, allowing maintenance needs for MW ground-mounted systems to be identified early.
Individual string current measurement
Recording and evaluation of current values for every single PV string. Advantages:
■ Rapid identification of underperformance
■ Early detection of string deviations
■ Data-driven performance analysis
■ Self-powered via DC/DC
The internal electronics are powered from the DC side via an integrated DC/DC power supply. This means no external auxiliary power connection is required, simplifying installation and system integration.
More transparency – fewer service calls
The combination of monitoring, fault discrimination, and remote communication creates a system that:
■ Automatically localizes faults
■ Minimizes downtime
■ Reduces service calls
■ Sustainably lowers OPEX
■ Ensures system availability
Fachmedien und Presseberichte zur Super Multi Box
Comparison: Super Multi Box, Custom String Combiner Box, or GAK Lite
Which DC combiner solution fits your project?
Super Multi Box
Intelligent DC Combiner
Smart DC combiner with active fault detection – developed for central inverter architectures and utility-scale PV systems with advanced analysis and optimization requirements
Custom String Combiner Box
DC Combiner
Individually planned DC combiner box for PV systems up to 1,500 V DC – ideal for technically demanding commercial, industrial, and PV power plant systems
GAK LITE
Standard Solution
Standardized string box for 1 | 2 | 3 MPPT with surge protection – for projects with clearly defined standard requirements
Planning, Production, and Testing in Germany
Every Super Multi Box and every Q3 generator junction box is planned on a project-specific basis, electrically designed, and fully manufactured in Germany. From dimensioning and mechanical integration to final testing, every step follows defined quality standards – transparently documented and tailored to the respective system.
The Super Multi Box is not just a component assembly, but a tested system solution. The combination of:
■ Custom design
■ Selective fault isolation
■ Integrated measurement technology
■ Communication interfaces
creates a technically coordinated DC combiner system for high system availability, long-term operational reliability, and reduced service calls in the MW range.
Particularly in utility-scale and MW ground-mounted systems, the electrical design of the DC combiner system determines system availability, service effort, and long-term operational reliability.
Project Inquiry DC Combiner Super Multi Box
Would you like to have the Super Multi Box designed for your PV project – including PV String Fault Discriminator, optional individual string current measurement, communication (Modbus/Ethernet), and matching protection components?
Using the inquiry form below, we capture your project data in a structured and transparent manner – so that you quickly receive a technically suitable and economical system solution.
You are welcome to send string plans, wiring/circuit diagrams, inverter data, Isc values, as well as grounding and protection concepts directly. Based on this, we check the boundary conditions (including number of strings, architecture, monitoring requirements) and configure the Super Multi Box to fit your project. If any questions arise, we will coordinate the details directly with you – otherwise, you will receive a project-specific offer promptly.
Project Inquiry Super Multi Box
Form for the project-specific design of your Super Multi Box – including PV String Fault Discriminator, SPD, individual string current measurement, and communication interfaces.
Technical Documentation DC Connection Technology
Super Multi Box datasheet, technical specifications, interface description, tender texts, and relevant documentation for intelligent DC combiner technology.
DC Combiner Super Multi Box
Super Multi Box – intelligent DC combiner up to 1,500 V DC with patented PV String Fault Discriminator, selective fault isolation, and individual string monitoring.
Generator Junction Box (GAK)
Individually configured DC combiner solutions without active fault discrimination – suitable for conventional system architectures or project-specific special requirements.