Power Supply for Solar Tracking Systems
A solar tracker power supply must be specified for the actual electrical branch: controller, sensors, communications or motor drive. These are not interchangeable loads. Before requesting a quotation, identify the available input, the required behavior during a supply loss, and which subsystem owns safe stowing. A small AC-to-DC supply may serve a protected logic branch, but it is not automatically suitable for direct photovoltaic input or tracker-motor operation.
The photographed WEHO MS-25-12 is a useful example of a compact auxiliary candidate: its original label and retained model sheet identify 12 V and 2.1 A. This article uses that exact specimen to illustrate an AC-fed controller procurement process—not to qualify a complete solar tracker.
Separate the power architecture before comparing suppliers
Ask the tracker integrator for a one-line power diagram and operating-state list. A site with an available AC service differs fundamentally from a controller powered by a PV string, a battery or a dedicated low-voltage bus. The input terminals, protection and operating windows must match the chosen architecture. Do not use an AC supply’s model name as evidence that it includes an MPPT charger, battery management or direct-string input capability.
| Branch | Information required for the RFQ |
|---|---|
| Control logic and position feedback | Allowed voltage range, startup current, active and standby consumption, restart sequence |
| Communications | Transmit bursts, required uptime, isolation and shared-return constraints |
| Motor or actuator drive | Loaded start, stall, reversal, duty cycle and returned energy; qualify separately |
| Emergency or weather-related stow | Required energy source and command behavior when normal power is unavailable |
This separation helps purchasing compare equivalent quotations. A controller-only offer should not be accepted as a replacement for a motor-and-controller supply merely because both outputs are called 12 V. Likewise, a normal-operation load schedule does not establish the energy needed to move the tracker to a required position during a power interruption.
Use the exact model as the configuration baseline
The retained MS-25-12 specimen is marked INPUT 100–240 VAC, 0.6 A, 50/60 Hz and OUTPUT +12 V, 2.1 A. Its full sheet specifies the 12 V model at 0–2.1 A and gives a chassis envelope of 84 × 58 × 38 mm. Those figures describe the component; they do not establish the final controller enclosure’s usable current at a particular internal temperature.
There is a material document discrepancy: the current WEHO MS-25 product table lists 5 A for its 12 V column, unlike the original photograph and matching retained sheet. The web input table also differs from the retained sheet. Ask for the offered revision’s photograph and matching specification, then resolve the discrepancy in writing before releasing a purchase order. Do not combine the most favorable values from different records.
Budget the essential load at its receiving terminals
Build a load schedule with current in sleep, normal tracking, communication and restart states. Include any simultaneous events, such as a controller booting while its radio transmits. Check the minimum voltage at each receiver after cable and protection-device losses. A label rating measured at the supply terminals is not the same as usable voltage at a distant sensor.
Define an acceptance margin with the supplier rather than applying an unsupported universal percentage. Provide the actual enclosure temperature and load profile so the offered revision can be checked under the intended conditions. If the logic branch must remain alive through an interruption, request a qualified power-path or backup arrangement; the small supply itself does not establish stored-energy capability for the tracker.
Keep the vented component in a suitable protected compartment
The MS-25-12 has a vented metal chassis and five front terminals behind an amber guard. Its compact case is not an outdoor weatherproof enclosure. Specify the cabinet location, expected condensation, dust, insects, cable entry and maintenance access. The final enclosure and ventilation strategy need their own environmental and thermal verification.
Use the original fixing features and leave working space for wiring, protective bonding and inspection. Confirm the matching revision’s terminal instructions before assembly. The retained sheet’s −10 to 50 °C working-temperature range is component information, not permission to expose the supply to sunlight, rain or an unmeasured cabinet hot spot.
Make the prototype test answer a purchasing decision
Agree pass/fail criteria before ordering evaluation samples. At minimum, test the specified input range, receiver voltage during each logic-load event, cold restart and recovery after interruption in the intended closed cabinet. Exercise the controller’s fault and stow-command behavior through the system integrator’s approved procedure. Supply qualification must not bypass the tracker manufacturer’s mechanical or functional-safety process.
Retain the accepted supply revision, controller firmware, wiring diagram and test conditions with the sample record. For repeat orders, request traceability and notification of changes that could affect input behavior, protection, terminal arrangement or thermal performance. A substitute with the same nominal output still requires comparison against these interfaces.
Buyer questions
Can this AC supply be connected directly to a solar panel?
Not on the evidence used here. This article qualifies an AC-fed auxiliary concept only. Direct PV input requires its own operating-window, transient, protection and control evidence; no MPPT or charging function is established for this specimen.
Does 12 V, 2.1 A establish that it can move the tracker?
No. That component rating does not establish motor starting, stall response, regenerative-energy handling or stow-energy availability. Give the drive-system requirements to the supplier and qualify that branch separately.
To request a relevant proposal, send WEHO the power architecture, essential-load schedule, cabinet conditions and required sample checks. Include evaluation and production quantities, destination and required documentation; availability, delivery terms and the final offered revision must be confirmed for the order.
