How to Use the Lexin Smart Pump P4
User Guide
Product Information
Product Model: Smart Pump P4
Input: USB-C / Output: USB-A, 5V/2A
Battery Power: 14.8 Wh / 7.4 V
Product Size: 155*68*42 MM
Battery Capacity: 3.7 V / 4000 mAh
Pressure Range: 2-150 PSI / 0.1-10.3 BAR
Product Net Weight: 427G
Working Temperature: -10 - 45°C
Package Contents
- Smart Air Pump
- Presta Valve Adapter
- Storage Bag
- Ball Valve Needle
- USB-C Charging Cable
- Quick Connect Air Hose
- American Style Valve Adapter
Introduction to Functions
Air Hose Interface: Connects to the air hose.
LED Light: Provides illumination.
USB-C Input Port: For charging the device.
USB-A Output Port: For charging external devices.
Real-time Air Pressure Display: Shows the current air pressure.
Battery Indicator: Displays the remaining battery level.
Usage Scene Display: Indicates the selected inflation mode.
Air Pressure Unit Display: Shows the selected pressure unit (PSI, BAR, KPA, Kg/cm²).
Preset Air Pressure Display: Shows the target air pressure.
Power Button: Turns the device on/off.
Mode/LED Light Configuration Button: Cycles through light modes and inflation modes.
Preset +/- Buttons: Adjust the preset air pressure.
Basic Operation
Power On/Off
To turn on: Press and hold the power button for 3 seconds.
To turn off: Press and hold the power button for 3 seconds.
Pumping Method
Once powered on, briefly press the power button to start inflating. The pump will automatically stop when the preset air pressure is reached.
Battery Indicator
- Green: 70% - 100%
- Yellow: 30% - 70%
- Red: 5% - 30%
- Flashing Red: Less than 5% (low battery alert, charge the device).
Charging Method
Use the USB-C input port (5V/2A) with a compatible charging cable and power adapter (sold separately) to charge the air pump. The green light flashes while charging and stays solid when fully charged. Note: The air pump cannot be used while charging.
Changing Air Pressure Units
Briefly press the 'U' button to cycle through the available pressure units (PSI, BAR, KPA, Kg/cm²). Conversion formulas: 1 PSI = 6.89 KPA; 1 BAR = 100 KPA; 1 Kg/cm² = 98 KPA.
LED Light Modes
Press and hold the light button to cycle through the LED light modes: solid on, strobe, SOS, and off.
Preset Air Pressure
Adjusting Preset Pressure: Briefly press the +/- buttons to adjust the preset air pressure by 0.5 PSI. Press and hold the +/- buttons to adjust the pressure rapidly.
Note: The device automatically saves the last used scene and preset pressure. The next time you use it, it will default to those settings.
Checking Air Pressure
With the pump in standby mode, connect the air hose to the object to be inflated. The upper half of the display shows the currently measured air pressure.
Measured Air Pressure: [Display of current pressure]
Preset Air Pressure: [Display of preset pressure]
Pressure Reset
If the air hose is not connected after powering on and the measured pressure is not 0.0, press and hold the '+' and '-' buttons simultaneously for 2 seconds to reset. The screen will flash all lights upon reset. Note: The default preset pressure has been reset to zero. Manual reset can improve accuracy if the measured pressure is not zero due to altitude or sensor differences. Calibration is not recommended at high temperatures.
Application Scene Selection
Briefly press the light button to select from 5 application scenes:
| Scene Mode | Default Value | Adjustable Range |
|---|---|---|
| Balls ⚽ | 8 PSI | 2-15 PSI |
| Bicycle ? | 38 PSI | 2-150 PSI |
| Motorcycle ?️ | 2.7 BAR | 0.1-3.7 BAR |
| Motor Vehicle ? | 2.4 BAR | 0.1-4.4 BAR |
| Custom ⚙️ | 100 PSI | 2-150 PSI |
Check Inflation Pressure
For safety, always check the required inflation pressure for the object according to its manual before inflating to prevent personal injury from over-inflation.
Connect Air Hose to Valve
Schrader Valves
Mountain bikes, electric bikes, motorcycles, and motor vehicles typically use Schrader valves. Connect the Schrader valve to the quick-connect air hose.
Quick Connect Air Hose: [Connection hose]
Schrader Valve: [Schrader valve connector]
Presta Valves
For road bikes and some mountain bikes, a Presta valve adapter is required.
- Connect the Presta valve adapter to the Schrader valve on the high-pressure air hose.
- Unscrew the Presta valve cap.
- Connect the Presta valve to the adapter for inflation.
Quick Connect Air Hose: [Connection hose]
Presta Valve Adapter: [Presta valve adapter]
Presta Valve: [Presta valve connector]
Ball Valves
Ball valves are needed for inflating balls like basketballs and footballs.
Inflating: After connecting the ball valve to the Schrader valve on the air hose, insert it into the gas filling hole to inflate.
Quick Connect Air Hose: [Connection hose]
Ball Valve: [Ball valve connector]
Gas Filling Hole: [Gas filling hole]
Power Bank
The smart air pump has a 4000 mAh battery. The 5V/2A USB-A output port can be used to charge electronic devices like mobile phones. Note: Inflation and charging cannot be performed simultaneously.
Common Object Air Pressure Values
| Product Category | Product Type | Pressure Range |
|---|---|---|
| Bicycle ? | Children's Bicycle (0-16 inches) | 18~30 PSI |
| 20-30 inch Tires | 30~45 PSI | |
| Mountain/Electric Bicycle | 38~55 PSI | |
| Road Bicycle | 100~120 PSI | |
| Balance Bike | 40~60 PSI | |
| Wheelchair | 30~45 PSI | |
| Motorcycle/Electric Motorcycle ?️ | Motorcycle/Electric Motorcycle | 1.8~3.0 BAR |
| Motor Vehicle ? | 2.2~2.8 BAR | |
| Ball ⚽ | Children's Toy Ball | 3~6 PSI |
| Basketball ? | 7~9 PSI | |
| Football ? | 10~12 PSI | |
| Volleyball ? | 4~6 PSI | |
| Rugby Ball ? | 10~14 PSI |
Attention
- Do not leave unattended during inflation.
- Do not place the air pump near flammable or explosive materials.
- Avoid sand ingress and drops.
- Do not place the product in extremely cold, hot, or humid environments.
- This product contains a built-in lithium battery. Do not discard it in fire or dispose of it arbitrarily.
- Keep this product out of reach of children.
Safety Precautions for High Temperatures
When the air hose is unscrewed, it and its joint may become very hot due to prolonged use. Avoid touching them with your hands for extended periods.
High Temperature Warning: [High temperature symbol]
Troubleshooting
| Problem | Solutions |
|---|---|
| Inflating too slowly | 1. Check if the battery power is sufficient. 2. Check for air leaks in the air hose. 3. Ensure connections at both ends of the hose are tight. 4. Check if the inflated object has air leaks. |
| Cannot inflate | 1. Check if the battery power is sufficient. 2. Check if the current tire pressure is higher than the preset value. |
| Cannot adjust preset pressure | 1. Verify the pump is in the correct inflation mode. Select the custom mode to adjust the preset value within the range of 2-150 PSI. |
| Inflates correctly, but pressure display shows zero | 1. Low-pressure items, like balloons, may be outside the device's measurable range. 2. For a completely flat tire, a brief inflation period is needed for the pressure value to display correctly. |
| After connecting the valve, the air pump automatically shut off | The pump automatically shuts off after 3 minutes of inactivity. Press and hold the power button to turn it back on. |
| Air leak when connecting the hose | Tighten the air hose connection. |
| Indicator light color is inconsistent between standby and inflation states | The lithium battery's voltage may drop significantly during discharge, causing this phenomenon. This is not a malfunction. |
| Power indicator does not light up after charging | Replace with a safe and compatible charging cable and adapter for recharging. |
