Decentralized solar tracker (Dual-Row)

STI-H250 TM is the most versatile solar tracker on the market. Can be adapted to uneven terrain with slopes of up to 15% in N-S and without limits in E-O

STI-H250™ horizontal single-axis solar tracker

The STI-H250 TM solar tracker consists of two torsion beams oriented in a North-South direction on which the photovoltaic modules are supported. Both rotate following the East-West movement of the sun.

The tracking control system is programmed with an astronomical calculation algorithm of the sun's path. It includes Backtracking mode to avoid the generation of shadows between adjacent rows that improves production by up to 5%, as well as the stow function to protect the tracker in extreme wind conditions.


The STI-H250 TM is a solar tracker with a rotation range of +/-55º, specially designed for projects where the terrain has significant changes in slope or where the ground is very uneven.

With the STI-H250 TM tracker, it is possible to optimize the cleaning of modules by placing each row in the desired position, thus achieving the simultaneous cleaning of modules of adjacent trackers. In addition, spaces between trackers are passable for vehicles

This tracker adapts perfectly to irregular layouts, making full use of the available land area. It is indicated for terrain with expansive clayey soils.

Adaptability to terrain, designed to adapt to all types of slopes

Adaptability to terrain, designed to adapt to all types of slopes

Versatile layout, indicated for uneven terrain

Versatile layout, indicated for uneven terrain

Effective and proven control, effective and reliable control system

Effective and proven control, effective and reliable control system

Control and Communications System

The STI-H250 decentralized solar tracker includes a control and communications system with the following characteristics:

  • Self-powered from a photovoltaic module with backup battery.
  • Wireless: Wireless communications system with ZigBee® technology
  • COMMUNICATIONS CONCENTRATOR: An NCU concentrator for every 200 STi-H250 trackers (with ZigBee wireless technology)
  • AUTONOMOUS STOWING: autonomous stowing to protect the structure and the photovoltaic modules in extreme wind conditions.
  • ALARMS AND STATUSES: Easy implementation in the plant’s SCADA system for performing O&M tasks.
  • CUSTOMIZED BACKTRACKING: The Backtracking algorithm alters the position of each tracker according to the height of the adjacent trackers, avoiding shadows and optimizing the production of the photovoltaic modules.

Instalation and maintenance

Thanks to the simplicity of its structure and its modular design, minimal installation time is required. In addition, the learning curve for its assembly is very fast, eliminating downtime and enabling the quick training of installers.

For this:

  • 100% bolted joints. No need for welding, cutting or drilling for its installation.
  • Great adaptability to terrain and adjustment. High tolerances for foundation positioning error, both on the three axes (X, Y, Z) and rotation on the Y and Z axes.
  • Assembly tools provided to facilitate assembly without needing constant metric verifications.
  • The height of the photovoltaic modules is approximately 1.35 meters, a convenient height  for their assembly.
  • It is not necessary to use ladders to assemble the STI-H250 tracker and the photovoltaic modules.

What's more, the wide variety of foundations to which it adapts means the STI-H250 tracker is installable on all types of terrain, minimizing and even eliminating the need for earth moving. The different types of foundation available are:

Installation types available

Direct pile driving

Direct pile driving:

Indicated for cohesive soils of medium-firm consistency and granular soils of medium to dense consistency.

Pile driving with pre-drilling

Pile driving with pre-drilling:

Indicated when direct pile driving is not possible due to the presence of localized rocky areas.

Concrete micropile

Concrete micropile:

Indicated for soils with poor geomechanical properties, high aggressiveness or presence of rock.

Screw pile

Screw pile:

Indicated for soils with a high content of vegetation and also for mixed soils with deep layers of rock and granular strata on the surface.

Concrete pad

Concrete pad:

Indicated for landfill areas.

Technical specifications

General characteristics
Type of structureHorizontal single-axis tracker (HSAT) – DUAL-ROW
Estimated surface area per 1 MWp2 ha (1/GCR=3)
Dimensions (STANDARD tracker with 72 cell modules and 1/GCR = 3 )
Modules per torsion beamUp to 60 (vertical configuration)
Installed peak power (350 Wp module)42 kWp
Total installed module area:  250 m2 / 2,691 ft2
Module height. Tracker in 0 horizontal position1.35 m / 4,43 ft
Module height. Tracker in 55 horizontal position2.25 m / 7.28 ft
Rotation drive
Type of driveRotary electromechanical transmission
Drive assembly power inputSelf-powered / Powered from the grid
Drive assembly power consumption< 0.45 kWh/day
Motor power100W / 24VDC
Mechanical specifications
Rotation rangeUp to +/- 55º
Max wind speed (in horizontal position)140 km/h (configurable for each project)
StructureHot-dip galvanized steel or Magnelis
Control system
Tracking controlAstronomical algorithm (Tolerance ±0.1°)
Shadow managementCustomized backtracking algorithm
Wind managementStow table configurable by the user
Tilt sensorInclinometer
Communications standardModbus RS485 or Wireless (Zigbee®)
Maintenance periodMinimum
Ten-year structural warranty / Five-year product warranty

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