BEIER-Electronic LM2596S DC/DC converter – adjustable step-down voltage regulator
The BEIER-Electronic LM2596S is a compact DC/DC converter designed to provide a reliable power supply for electronic components in model-making. As a step-down switching regulator, the module efficiently converts a higher DC voltage into a lower, stabilised output voltage. This allows various loads to be powered directly from the existing drive battery, without the need to fit an additional battery in the model.
The desired output voltage is precisely adjusted using a potentiometer. The converter is preset to 5.0 V as supplied. Thanks to an efficiency of up to 90 per cent, there are significantly fewer losses and less waste heat than with simple linear voltage regulators.
Versatile applications in model-making
The LM2596S is particularly suitable for functional models such as RC trucks, construction machinery, tanks, ships and special-purpose vehicles. For example, a 3S or 4S LiPo battery can be used to generate a lower supply voltage for receivers, sound modules, lighting controls or other additional electronic functions. In models with a 12 V or 24 V on-board power supply, this allows the operation of loads that require only 5 V, 6 V or 12 V.
The module can also be used as an external BEC power supply for an RC receiver and servos. In this case, the total current demand – including short-term servo peaks – must remain within the converter’s capacity. Several digital servos operating simultaneously, or particularly high-power digital servos, may require a more powerful BEC converter.
Other typical applications include powering Arduino, ESP32 and other microcontroller circuits, lighting electronics, small fans, pumps, relays or additional control modules. For motors, pumps and other inductive loads, the often significantly higher inrush current must be taken into account in addition to the normal operating current.
Connecting the DC/DC converter
The module has four solder terminals:
IN+: Input voltage positive
IN−: Input voltage negative or earth
OUT+: Output voltage positive
OUT−: Output voltage negative or earth
The input and output share a common earth and are not galvanically isolated from one another. It is essential to ensure correct polarity when connecting.
Before connecting the load, the output voltage should be checked with a multimeter and, if necessary, adjusted using the trimmer potentiometer. Only then should the electronics to be powered be connected to OUT+ and OUT−. An excessively high voltage setting can cause damage, particularly to receivers, servos, sound and lighting modules.
Note on the instructions
No additional or printed instructions are supplied with the DC/DC converter. All information required for connection, adjustment and safe operation is set out in this product description.
Important notes for model-making
The LM2596S is a step-down converter only. It can only reduce the existing voltage; it cannot increase it. The input voltage must therefore always be at least 2 V higher than the desired output voltage.
The converter should be connected directly to the battery or to a power distribution unit with consistent polarity. It must not be operated at the motor output of a speed controller capable of forward and reverse operation, as the polarity reverses there when the direction of travel changes.
Despite the stabilised output voltage, suitable current limiting via series resistors or a constant-current source is still required when connecting individual LEDs. In model boats and other applications susceptible to moisture, the exposed circuit board must be installed in a dry location and protected against splash water, conductive components, vibrations and short circuits.
Technical Specifications
Input voltage: 4–37 V DC
Output voltage: 1.25–35 V DC, continuously adjustable
Output current: 2 A continuous, up to 3 A for short periods
Factory-set output voltage: 5.0 V
Efficiency: up to 90%
Switching frequency: 150 kHz
Protection functions: Over-temperature, over-current and short-circuit protection
Design: Step-down switching regulator, not galvanically isolated
Dimensions: 43 × 21 × 14 mm
Weight: 10 g
