1. Introduction
The HQST 20A PWM Flush Mount Solar Charge Controller is designed to efficiently manage power flow from your solar panels to your battery bank, ensuring optimal charging and protection. It is compatible with both 12V and 24V battery systems, supporting various battery types including Lithium, Sealed (AGM), Gel, and Flooded batteries. This manual provides essential information for proper installation, operation, and maintenance of your solar charge controller.
2. Product Overview
Familiarize yourself with the components of your HQST solar charge controller:
This diagram illustrates the key components and dimensions of the HQST 20A PWM Flush Mount Solar Charge Controller. It measures approximately 5.11 inches in length and 3.54 inches in width.
- 5V 1A USB Port: For charging USB-compatible devices.
- Up & Down Button: Used for navigating display screens and adjusting settings.
- LCD Display Screen: Shows real-time system data and settings.
- Load Button: Controls the DC load output.
- Mounting Holes: For securing the controller during installation.
- Load Terminals: Connect to your DC loads.
- Battery Terminals: Connect to your battery bank.
- Solar Terminals: Connect to your solar panel array.
- Flat Mount Bracket: Optional bracket for surface mounting.
3. Setup
3.1 Mounting the Controller
The controller offers flexible mounting options:
The controller can be installed using either a flush mount for a seamless look or a flat mount with the provided bracket. Choose a location that is dry, well-ventilated, and away from direct sunlight or heat sources.
- Flush Mount: Integrate the controller directly into a panel or wall for a clean finish.
- Flat Mount: Use the included bracket to mount the controller on a surface.
Ensure adequate space around the controller for air circulation to prevent overheating.
3.2 Wiring Connections
Follow the correct wiring sequence to prevent damage to the controller or battery:
- Connect the Battery: First, connect the battery to the controller's battery terminals (7). Ensure correct polarity (positive to positive, negative to negative). The LCD will power on.
- Connect the Solar Panel: Next, connect the solar panel to the controller's solar terminals (8). Ensure correct polarity.
- Connect the DC Load: Finally, connect your DC loads to the controller's load terminals (6). Ensure correct polarity.
Disconnection Sequence: To disconnect the system, reverse the order: disconnect the load, then the solar panel, and finally the battery.
This wiring diagram illustrates the proper connection order for the solar panel, battery, and DC load to the HQST solar charge controller.
When connecting wires, ensure they are inserted into the correct square socket for the cable, not the screw hole. Fully unscrew the terminal screws, insert the wire ends, then tighten the screws securely.
3.3 Battery Type Setting
The controller automatically recognizes 12V/24V Sealed (AGM), Gel, and Flooded batteries. For Lithium batteries, manual parameter setting is required:
The LCD display allows for manual adjustment of battery parameters, especially crucial for Lithium-ion batteries.
- Press and hold the 'Up & Down' button to enter the setting mode.
- Use the 'Up & Down' buttons to navigate to the battery type setting (e.g., "b01" for Gel, "b02" for Sealed, "b03" for Flooded, "b04" for Lithium).
- For Lithium batteries, further adjust charging voltage, over-discharge voltage, and other parameters as per your battery manufacturer's specifications.
- Press and hold the 'Load' button to save the settings and exit.
4. Operating Instructions
4.1 LCD Display Navigation
The LCD screen provides real-time monitoring of your solar system:
The intuitive LCD screen cycles through various operational data, including battery voltage, PV voltage, charge current, load current, controller temperature, and battery state of charge (SOC).
- Press the 'Up & Down' button (2) to manually cycle through the displayed parameters.
- The display will automatically cycle through parameters if no button is pressed for a few seconds.
4.2 Load Control
The controller features a DC load output with multiple control modes:
- Press the 'Load' button (4) to manually turn the DC load output on or off.
- The controller supports 17 different load control modes, allowing for customized operation (e.g., dusk-to-dawn, timed operation). Refer to the full manual for detailed instructions on setting load modes.
4.3 USB Charging Port
The integrated 5V 1A USB port (1) can charge small electronic devices. This port is active when the DC load output is enabled.
4.4 4-Stage Smart Charging
The controller employs an advanced 4-stage charging algorithm to optimize battery health and lifespan:
This graph illustrates the voltage and current profiles during the 4-stage charging process, including Bulk, Boost/Absorption, Float, and Equalization stages.
- Bulk Charge: Delivers maximum current to rapidly charge the battery.
- Boost/Absorption Charge: Maintains a constant voltage to ensure the battery is fully charged without overcharging.
- Float Charge: Reduces voltage to a lower level to maintain the battery at full charge, compensating for self-discharge.
- Equalization Charge: (For lead-acid batteries only) Periodically overcharges the battery to balance cell voltages and prevent sulfation.
5. Maintenance
To ensure the longevity and optimal performance of your HQST solar charge controller, perform the following maintenance checks:
- Regular Inspection: Periodically check all wiring connections for tightness and signs of corrosion. Loose connections can cause voltage drops and overheating.
- Cleanliness: Keep the controller's exterior clean and free from dust, dirt, and debris. Use a dry cloth for cleaning. Do not use harsh chemicals or abrasive materials.
- Ventilation: Ensure that the installation area remains well-ventilated to allow for proper heat dissipation. Blocked vents can lead to overheating and reduced efficiency.
- Battery Health: Monitor your battery's health and performance regularly. Follow the battery manufacturer's maintenance guidelines.
6. Troubleshooting
If you encounter issues with your solar charge controller, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Controller Display is Off | No power from battery or incorrect battery connection. | Check battery connections and ensure correct polarity. Verify battery voltage is above the minimum operating voltage. |
| Battery Not Charging | No solar input, incorrect solar panel connection, or faulty solar panel. | Ensure solar panels are receiving adequate sunlight. Check solar panel wiring for correct polarity and secure connections. Test solar panel voltage. |
| DC Load Not Working | Load output disabled, incorrect load connection, or over-discharge protection active. | Press the Load button to enable output. Check load wiring for correct polarity and secure connections. Verify battery voltage is above the over-discharge protection threshold. |
| Error Code Displayed (e.g., E02) | Specific system fault (e.g., E02 typically indicates over-discharge). | Consult the full product manual for a complete list of error codes and their corresponding solutions. Address the underlying issue (e.g., charge battery for E02). |
If the problem persists after attempting these solutions, please contact HQST customer support.
7. Specifications
| Feature | Specification |
|---|---|
| Model | 20A PWM Flush Mount |
| System Voltage | 12V / 24V Auto-recognition (Lithium batteries require manual setting) |
| Max Charge Current | 20A |
| Battery Compatibility | Lithium, Sealed (AGM), Gel, Flooded |
| Charging Stages | 4-Stage (Bulk, Boost/Absorption, Float, Equalization) |
| USB Output | 5V 1A |
| Display Type | LCD |
| Product Dimensions (L x W x H) | 5.11 x 3.54 x 1.36 inches |
| Item Weight | 9.1 ounces |
| Max Operating Temperature | 45°C (113°F) |
| Protection Features | Reverse polarity, over-voltage, over-current, over-discharge, short-circuit, reverse current. |
8. Warranty and Support
This HQST product is backed by a 10-year warranty, reflecting our commitment to quality and durability. For any technical assistance, troubleshooting, or warranty claims, please contact HQST customer support.
You can find contact information and additional resources on the official HQST website: www.hqst.com
Please have your product model number (20A PWM Flush Mount) and purchase details ready when contacting support.
