3A DC Step Down Module Adjustable Buck Converter High Precision 5-27V to 1-24V CV CC Unassembled

3A DC Step Down Module Adjustable Buck Converter High Precision 5-27V to 1-24V CV CC Unassembled



Attention:
- The output voltage range of its USB port is adjustable from 1 to 24V, not absolute 5V. Please verify before connecting your USB device.
- Acrylic shell, heat sink, copper pillars, screws and other accessories are included. Please assemble it by yourself.
- The module is a DC to DC step-down module. It is not allowed to input AC voltage directly reduced by a transformer. Never exceed input voltage. To increase safety factor, it is recommended that a 3A fuse be connected in series to the input end of power supply module. It is is a buck module, and input voltage needs to be 2V higher than output voltage. It is possible that output voltage cannot be adjusted because the position of the potentiometer is higher than input voltage. You can first adjust CV potentiometer counterclockwise twenty turns to see whether output voltage changes or not.

Note:
- Assembling is needed.
- Batteries are not included.

Features:
- Easy to adjust voltage and current via long knobs
- High precision calibration, self-calibration of input and output voltage, output current, voltage accuracy of 0.01V, current accuracy of 0.001A.
- Various protections. Anti-reverse connection protection: allow reverse connection and module will not burn out. Anti-backflow: Connect to battery directly, don't worry about battery flow-back causing the module being burned out. No another string of diodes needed. Over-current protection: the output is short-circuited and not burned, and current limit of rechargeable battery is safe.
- With DC5.5 input port, with USB adjustable voltage output interface.
- Displays input and output voltage, output current, power, and capacity display.
- Output ripple is extremely small, and the output has LC filtering.

Specifications:
1. Input voltage: 5-27V (The input voltage needs to be higher than output voltage by 2V. If you want to output 5V, input voltage must be above 7V. When output voltage cannot be adjusted, it may be because the position of the potentiometer is higher than input voltage. You can first adjust CV potentiometer counterclockwise twenty turns to see whether output voltage changes)
2. Output voltage: 1-24V (If output voltage is higher than 24.5V, the output will be automatically turned off and OV will be displayed. After lowering output voltage, press ON / OFF button to solve the problem)
3. Output current: The maximum output is about 3A. Recommended for use within 2.5A. When the module is hot, you need to solve the heat dissipation problem by yourself. The output current in constant voltage mode is adaptive according to load size and is not adjustable. (The adjustable limit current is about 3A maximum. When output current exceeds 3A, the output is automatically turned off and OC is displayed. After reducing load current, press ON/OFF button to solve it)
4. Output power: less than 30W (When output power is greater than 30W, the output is automatically turned off and OP is displayed. After reducing load power, press ON/OFF button to solve)
5. Voltage display: resolution 0.01V, factory precision ± 0.1V (If users require high accuracy, it can be manually corrected after comparing with a standard voltmeter)
6. Current display: Resolution 0.001A, range 0-3A, factory precision ± 0.05A. When output current is less than 0.05A, display error is large. Small current within 10-40mA cannot be displayed (If users require high accuracy, it can be manually corrected after comparing with a standard ammeter. When output current is greater than 1A, calibration is more accurate)
7. Capacity display: resolution 0.001Ah, range 99.99Ah (can be cleared by long-pressing '-' key. Data is automatically saved after power-off. Values are automatically accumulated after power-on. Saturation is reached after reaching 99.99Ah, which needs to be manually reset)
8. Conversion efficiency: less than 95%
9. Working current: about 30mA
10.Input reverse connection protection: Yes
11.Output end anti-backflow: Yes. Can be directly connected to battery for charging without a diode (the output end of the module has a 1K ohm equivalent dummy load. After charging is complete, connecting battery continuously will drain the battery. To solve this problem, please connect a diode in series with output terminal)
12. Short circuit protection: Yes
13. Size: 73.4mm * 55.54mm * 30.5mm (L*W*H)
14. Weight: 67.8g (including accessories)



Functions:
1. Buttons:  
"+" button: long press to enter or exit accuracy calibration interface. Short press: the current correction value needs to be increased by one unit;

"-" button: long press to clear capacity value; short press: the current correction value needs to be reduced by one unit;

"SELECT" button: long press to switch between current, power and capacity display; short press: switch between input voltage and output voltage display;

"ON / OFF" button: long press to set default output to on/off by default when power on; short press: control the output to turn on or off.

2. Potentiometer Knobs:
On the left is current adjustment potentiometer CC. Turn clockwise to increase the set current. When load current reaches the set current, it enters constant current state (Please note that adjusting the potentiometer cannot always increase output current. Under constant voltage, output current depends only on a load, which varies according to the load);

On the right is voltage regulating potentiometer CV. Turn clockwise to increase  output voltage (This is a step-down module. Input voltage must be 2V higher than output voltage. If output voltage cannot be adjusted, first adjust CV potentiometer counterclockwise to the end).

3.Indicators:
CC: Constant current indicator. It is lit (red) when constant current;
Full: Battery fully charged indicator (green). For example, we set constant current value to 2A. Lights change when when charging current reaches below 0.2A, Full indicator is on, and Charge indicator is off;
Charge: battery charging indicator (blue);
ON: output status indicator (green).

4. Input & Output Ports:
Input: On the left. DC5.5mm socket or 5.08mm terminal as input;
Output: On the right. USB port or 5.08mm terminal as output, can also output at the same time (The voltage of USB port is not absolute 5V, and the terminal is directly connected. Adjustable range is 1-24V)

Accuracy Calibration Method:

Input voltage calibration: Long press "+" key to enter SET interface, the current display is input IN voltage. Short press "+" or "-" key to adjust, long press "+" key to exit SET interface;

Output voltage calibration: Press and hold "+" key to enter SET interface. The current display is input IN voltage. Press "SELECT" button once to switch to OUT voltage display. Short press "+" or "-" key to adjust, long press "+" key to exit SET interface;

Output current calibration: Press and hold "+" key to enter SET interface. The current display is input IN voltage. Press "SELECT" button once to switch to OUT voltage display. Press "SELECT" button again to switch to display output current interface. After short-pressing "+" or "-" key to adjust, press and hold "+" key to exit SET interface. Attention: Calibration is more accurate when current is greater than 1A. When output current is less than 0.05A, display error is large. When output current is less than 10-40mA, it may not be displayed.

Precautions:
1.The input IN- of the module is forbidden to be short-circuited with the output OUT-, otherwise constant current function is invalid.
2.Make sure that the power of power supply is greater than the power required by an output load. When the module is hot, please reduce the power!
3.Please read the product description carefully before using.
4.Electronic knowledge is highly recommended.
5.The product is not designed for medical, life saving, life support and other purposes, and cannot be used in hazardous places such as coal mine depots.

Package Included:
- 1 x Set of Step Down Module