REDARC DPS2420 24V 20A in-vehicle DC power supplyRegulated 24V 20A DC power supply, 9–32V input

Overview

The DPS2420 delivers a regulated 24V at 20A, with 40A surge, from a 12V or 24V vehicle supply of 9–32V. It suits 24V lighting, pumps, communications or other equipment fitted to 12V vehicles, and can be paralleled with a second unit for more current. Output voltage is selectable at 24.0V, 27.4V or 29.0V. REDARC recommends a 60A FK60 fuse on the input and a 40A FK40 fuse on the output, and chassis mounting outside the engine bay.

• Input 9–32V from 12V or 24V vehicles
• 12V models 25A/40A, 24V models 10A/20A
• Three output voltages selectable by wire
• ±1% line and load regulation, over 94% efficiency
• Ignition-controlled to protect the start battery
• Two units can be paralleled for more current

How it works

The DPS series are switch-mode DC-DC converters for powering loads, not for charging batteries, which REDARC explicitly forbids. Their input can be above, below or equal to the output, so a DPS1225 or DPS1240 gives a stable 12V supply from a 24V truck, and a DPS2410 or DPS2420 gives 24V from a 12V vehicle. Typical loads named by REDARC include lamps, radios and communications equipment, computers, small motors, fridges, pumps and TVs, and the units generate little electrical noise.

The blue wire connects to ignition or a dedicated switch, so the output only runs with the vehicle on and cannot flatten the start battery. If voltage drop on the input cable becomes excessive, the DPS reduces its input current to protect the wiring.

Key features

The orange wire selects the output: 12.0V, 13.7V or 14.5V on the 12V models and 24.0V, 27.4V or 29.0V on the 24V models, regulated to ±1% with a ±0.12V tolerance. Rated outputs are 25A and 40A (surge 50A and 80A) for the 12V units and 10A and 20A (surge 20A and 40A) for the 24V units. All share a 150×120×37mm, 680g housing with conversion efficiency above 94% and operation from -50°C to +50°C.

Installation and compatibility

The DPS must not be installed in hot areas such as the engine bay; it performs best mounted to the vehicle chassis, which acts as an external heatsink, and output derates above 55°C. Keep the output cable to the load under 1m. REDARC specifies MIDI fuses (FK40 or FK60 kits) and at least 7.71mm² cable for 1–5m on DPS1225 and DPS2410, or 13.56mm² for DPS1240 and DPS2420.

On vehicles with an earth isolation switch, the black wire must go to chassis earth, not the battery negative, so the DPS is disconnected with the vehicle. Two identical units can be connected in parallel, mounted close together on the chassis with matching wire lengths; two DPS1240s, for example, supply up to 80A.

Status indication

Three LEDs show the selected output voltage and a fourth the output status, blinking with a duty cycle that rises with current and lit solid at full power. An external LED can be wired to the green wire, which is current-limited to 6mA. Fault codes indicate internal faults, over-temperature, output or input over-voltage and reverse polarity.

Questions and answers