SDC-5330 / 5340
Programmable DC-DC Converter with battery charger function
This MCU controlled Step Down 24V to 12V DC-DC converter has a programmable output 12.0 to 15.0V
It can also be set up as a Two Stage Battery Charger.
The 3 LED display shows output voltage and current in turn or selectively as desired.
When unit is in protection mode, 8 codes can be shown for different fault diagnosis.
Programmable output voltage (12V-15V DC in 0.2V step) makes it ideal for voltage sensitive devices.
As a 2 stage full powered charger mode with 14.3V Boost and 13.6 V float charge.
3 digit LED display for Voltage, Current, Operation Mode and Protection Diagnosis.
Remote Voltage sensing for optimal and accurate powering of distant load or battery.
Ignition terminal for automatic On/Off with car’s ignition control or other external On/Off Switch.
The function of Ignition terminal can be set to on or off.
Remote alarm terminal (13.5V, 0.25A) for Input under voltage alarm connection.
A separate always-on auxiliary output (13.8V, 0.5A) to power critical electronic.
Device such as security device or remote on off switch.
Eight protections with code at the display, seven protections are self recoverable.
Thermostatic cooling fan.
When an inductive load such as motor, solenoid, headlight, or other electro mechanical device, the
supplied accessory, a diode (400V, 3Amp) must be installed across the load as shown in (Connection
Diagram 1) to protect the converter from the high fly back voltage spike from the load when the supplied
voltage is cut off or decreased abruptly.
When the fuse is broken, DO NOT replace the fuse before ceasing the problem that caused the broken
fuse. Use the same type and rating of the original fuse.
Avoid touching the heat sink panel during operation of the unit as the heat sink may heat up to burn your
3 digit LED. Show voltage, current, operation and fault diagnosis.
Indicate LED value is Voltage (V) or Current (A).
Indicate converter is in charger mode.
Input, output and auxiliary terminal view
Ignition port (connect to positive 8 to 32V)
Always On Auxiliary Output
Positive 13.8V and 0.5A for LED warning for low input voltage
Voltage Remote Sensing Negative
Voltage Remote Sensing Positive
6.1 Connection Diagram 1
6.2 Connection Diagram 2 (Negative Ground)
INITIAL SET UP AND CONNECTION
Leave the output terminals isolated (connected to no devices or battery).
Connect 24V battery to input terminal. Double check correct polarity before final hook up.
There is only one “SET” button for programming.
Press and hold the “SET” button until
shows up and the display flashes to indicate.
Unit is ready for programming.
Subsequent short presses increase output voltage by 0.2V step in a loop.
Stop at the desired Output Voltage or at the
if you select to battery charger mode.
After a few seconds, the display stops flashing to indicate that the selected setting has been confirmed
and the unit will operate in the new set output voltage or as a battery charger.
Now you can connect the output terminal to a 12V device or 12V battery according to your set mode,
double checking for correct polarity before final hookup.
During operation, the LED display shows voltage and amps by turn.
Quick press to the button will either freeze the display (at desired V, A) or return to the default scrolling mode.
The display is off after 10 minute to conserve energy, it can be waken up again by a quick press of the button.
When the output current is less than 1 Amp or output is open circuited the LED display will show
indicating Low Output Amp.
This applies to both converter and charger mode.
In the charger mode, the when output float voltage is 13.6V, there is less than one Amp to the battery this
can be interpreted as Battery Full. In the converter mode
drawing from the output or output open circuit.
means either under 1Amp or no load
Remote Voltage Sensing
As a voltage converter it can be finely tuned to give your device the required voltage level (0.2V step). Even
when your device is at a distance, you can use the remote voltage sensing terminal (S-, S+) to ensure
accurate point of load voltage and further improves the stability of the load point voltage.
Ignition Port & Ignition Control Mode
When the Ignition Control is activated the unit will only operate when the vehicle’s engine is running or the
ignition has been tuned on.
Alternatively, apply a positive 8 to 32V to the ignition terminal as an on off switch for the unit.
Once the Ignition Control has been activated, the unit will be remained in Ignition Control Mode until it is
disabled either by reset
, or to
factory preset see section 11 and 12 for more detail information
There is an alarm terminal only for input low voltage alert (F05) which provides 13.5V, 0.25A for remote LED
to give out alert before converter enters into low voltage protection and shuts down. The alarm signal will be
on, once input is below 21V and signal is off when input rises back above 21V.
Battery Charger Mode - Two Stage Charger
When the unit is set at the Charger Mode, LED Display
the Charger Mode in operation.
, the charger icon
will be on to confirm
The Boost Charge constant voltage is set at 14.5V and the Float Charge voltage is at 13.6V.
The Charger Icon flashes in Boost Charge, and becomes solid in Float Charge.
Quick pushes to Set Button will show charging voltage and current.
Please note that when battery is full the float charge current is less than 1A and the current display shows
10. DISPLAY INDICATION
Low Current Display is shows up when output current less than 1 Amp
SELECTION (programmable) Mode, ready for programming of output voltage &
IGNITION CONTROL DISABLED, there is always output when input is powered up
FACTORY DEFAULT SETTINGS ENABLED (see section 12 for default settings)
Flashing = Boost Charge, Solid = Float Charge
11. IGNITION SWITCH CONTROL
This converter can be controlled by status of ignition switch. Ignition switch control is disabled by default.
To enable ignition switch control, just applying a positive 8 to 32V signal to ignition terminal.
After ignition control has been enabled, It keeps in enabled mode until you disable as following.
To disable ignition control
Press and hold “SET” button until
Release button then wait for a few seconds. The ignition control will be disabled.
12. FACTORY DEFAULT SETTINGS
1. Unit is in DC-DC Converter Mode with Output Voltage set at 13.6V
2. Ignition Control is disabled, that means the Output is always ON.
You can reset converter to factory default setting by following steps.
Press and hold “SET” button until
Release button then wait for few seconds. The converter will reset back to factory default setting.
13. DISPLAY ON/OFF
The display will be switched off automatically after 10 minutes of no action on the Set Button. Press the Set
Button to wake up display for another 10 minutes.
14. ALWAYS ON AUXILIARY OUTPUT
The DC-DC converter provide an always on auxiliary 13.8V, 0.5A to power critical device such as security
After connect input to 24V battery, the 13.8V terminal has output immediately.
15. REMOTE VOLTAGE SENSING PORTS
The remote voltage sensing works for both converter mode and charger mode, it compensates voltage drop
at distant load or auxiliary battery.
It further enhances the accuracy of output voltage to the distant load or battery and provides more stability
with varying output current.
Just connect AWG 22 wires between the Positive S+ to Positive of load / battery and Negative S- to Negative
of load/ battery.
The alarm signal port provides a 13.5V 0.25A for external LED to give pre-warning signal when input voltage
drops below 21V before 19V at which output shuts down.
17. LOW CURRENT DISPLAY
The display will show
when output current is less than 1Amp. Unit can be in converter or charger
mode or when output is open circuit. When in charger mode, it can be interpreted as battery full.
If no display comes up after connection to the input, check for correct input polarity.
Disconnect all wires to the unit and check the input fuse.
The LED shows error code when converter is in any protection mode.
The following table denotes the 8 Error Codes.
Over Temperature Protection (Self-recoverable)
When unit’s internal temperature becomes higher than the threshold value, unit shuts down
output. Unit will resume normal operation automatically once temperature becomes normal.
Output Over Voltage Protection (Self-recoverable)
In DC-DC Converter Mode, units shuts down output when output voltage is 15% higher than
the preset voltage level, unit is self recoverable at output voltage 1V less than the preset level.
In DC Charger Mode, at Boost Charge Stage, unit shuts down when output at voltage > 16V,
self recoverable at <15.5V Charge or at Float Charge Stage higher than 15.1V, self
recoverable at <14.6V.
Over Load Protection (Self-recoverable)
When Output current is 3 Amp higher than 40A for model SDC-5340, 30A for model SDC-5330,
the unit will shut down the output. Unit is self recoverable once output current falls back to
unit’s rated value.
Fan Fault (Self-recoverable)
When fan is stuck, or does not operate normally, the unit will shut down the output. Unit
resumes normal operation once the fan fault condition has been removed.
Input Low Voltage Protection (Self-recoverable)
Input V < 21V
Alarm signal On
Input V > 21V
Alarm signal Off
15V < Input V < 19V for 3 min.
Output shuts down, self recoverable > 25V
Input V < 15V
Output instant shut down self recoverable >25V
Output Short Circuit Protection (Self-recoverable)
Unit shuts down output when output short circuited.
Self recoverable when fault condition is removed.
Output terminal battery reverse polarities protection
When output terminal is connected to battery in reverse polarity, fuse is blown.
Replace fuse with correct rating.
Input over voltage protection (Self-recoverable)
When input voltage is higher than 35V, output shuts down.
Self recoverable when input drops to 32V.
Input Voltage Range
19 – 36VDC
Output Voltage Range
12 – 15VDC(0.2V increments)
Continuous Output Current
No load current
Over Voltage, Overload, Input Reverse Polarity, Over Temperature,
Output Reverse Polarity, Output Short Circuit, Input Under Voltage
Aux. Output (Always On)
13.8V / 0.5A
Two Stage Battery Charger
Boost Charge 14.3V, Float Charge 13.6V
Output Remote ON/OFF
Remote Voltage Sense
External Alarm Output
13.5VDC / 0.25A
3 digits LED display for V, A & Error code, Battery Charger Indicator
Thermostatic Control Fan
-10°C to +50°C
EN 55014, EN60335.2.29
Supplied 4 cable lug connectors, One 400V 3A diode