1. Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of your HQST 20A PWM Solar Charge Controller. This device is designed to manage the power flow from your solar panel to your battery, ensuring efficient charging and protecting your battery from overcharge and over-discharge. It is compatible with 12V and 24V PV systems and various lead-acid battery types.
2. Product Features
- 20A Solar Charge Controller: Automatically detects 12V or 24V PV systems.
- Battery Compatibility: Works with Sealed, and Flooded lead-acid batteries.
- Optimized Charging: Features an optimized 3-stage battery charging system to regulate electricity flow and prolong battery lifespan.
- Accurate LCD Display: Large digital LCD display clearly indicates working conditions and accurate operating data for real-time PV system monitoring.
- Comprehensive Protection: Provides reverse polarity protection, block reverse current at night, short circuit, overcharge, over-discharge, and overload protection for solar panel and battery.
- Easy Installation: Designed with corresponding icons on each connector for quick setup.
- USB-A Port: Includes a USB-A port for charging mobile devices or powering small loads.
- Multiple Applications: Suitable for RVs, cabins, workshops, garages, and other off-grid lighting or power needs.
3. Product Overview
Familiarize yourself with the components of your HQST Solar Charge Controller.
Figure 3.1: Front view of the HQST Solar Charge Controller with key components labeled, including mounting holes, LCD screen, control keys, solar panel terminals, battery terminals, load terminals, and USB port.
Figure 3.2: Detailed view of the LCD display, showing indicators for PV (solar panel), BAT (battery), LOAD, parameter digits, and units (kWh, %, V, °C). It also illustrates the power flow from solar panel to battery to load.
4. Specifications
| Feature | Specification |
|---|---|
| Model | 20A PWM |
| System Voltage | 12V/24V Auto |
| Max Charge Current | 20A |
| Battery Type Compatibility | Sealed, Flooded Lead-Acid Batteries |
| Display Type | LCD |
| USB Output | 5V/1A (USB-A Port) |
| Product Dimensions | 5.12 x 1.38 x 2.95 inches (13 x 3.5 x 7.5 cm) |
| Item Weight | 4.9 ounces (0.14 kg) |
| Manufacturer | HQST |
| UPC | 791810331544, 810081407366 |
Figure 4.1: Physical dimensions of the HQST Solar Charge Controller, showing length (6.45 in), width (4.07 in), and height (1.85 in).
Figure 4.2: Illustration of battery types compatible with the HQST Solar Charge Controller, including Sealed, Gel, Flooded, and Lead-Acid batteries.
5. Safety Instructions
- Ensure all connections are tight and secure to prevent loose connections that can cause excessive heat.
- Always connect the battery to the charge controller first, then the solar panel, and finally the load. Disconnect in the reverse order.
- Do not connect an inverter directly to the load terminals of the charge controller. Connect inverters directly to the battery.
- Install the controller in a well-ventilated area, away from direct sunlight, high temperatures, and moisture.
- Ensure the system voltage (12V or 24V) matches the battery bank voltage. The controller automatically detects this.
- Use appropriate wire gauges for all connections to prevent voltage drop and overheating.
- Wear eye protection when working with batteries.
6. Installation (Setup)
Follow these steps for proper installation of your solar charge controller.
- Mounting: Choose a dry, well-ventilated location for mounting the controller. Ensure there is sufficient space around the controller for heat dissipation. Use the mounting holes provided on the unit.
- Connect the Battery: Connect the battery to the battery terminals on the charge controller. Ensure correct polarity (+ to + and - to -). The LCD display should illuminate, indicating the controller has detected the battery voltage.
- Connect the Solar Panel: Connect the solar panel to the solar panel terminals on the charge controller. Ensure correct polarity. The controller will begin charging the battery if sunlight is available.
- Connect the Load: Connect your DC loads (e.g., lights, fans) to the load terminals. Ensure correct polarity. The USB-A port can also be used for charging compatible devices.
Important Connection Order: Always connect the battery first, then the solar panel, and finally the load. Disconnect in the reverse order: load first, then solar panel, then battery.
Figure 6.1: A typical wiring diagram showing the connection of a 12V solar panel, the HQST PWM charge controller, a 12V deep cycle battery, and a 12V power inverter. Note the recommended fuse placement and wire gauges.
Figure 6.2: Visual step-by-step guide for connecting the HQST Solar Charge Controller: 1. Connect the battery. 2. Connect the solar panel. 3. Connect the load (light bulb). This sequence ensures safe and proper system setup.
7. Operation
Once installed, the controller operates automatically. The LCD display provides real-time information about your system.
7.1 LCD Display and Button Functions
The LCD cycles through various parameters such as battery voltage, charging current, load current, and temperature. The single red button is used to manually cycle through display modes or to enter settings for load control (e.g., timer settings for lights).
- Short Press: Cycles through display parameters.
- Long Press (approx. 5 seconds): Enters or exits setting mode for load control.
7.2 Load Control
The controller offers programmable load control. You can set the load to turn on/off based on daylight or a timer. Refer to the specific settings menu on the LCD for detailed configuration. The USB-A port is typically powered when the load output is active.
Figure 7.1: The HQST Solar Charge Controller featuring a USB-A port, which can be used to charge mobile devices or power small USB-compatible electronics.
8. Maintenance
Regular maintenance ensures optimal performance and longevity of your solar charge controller.
- Inspect Connections: Periodically check all wiring connections for tightness and corrosion. Loose connections can lead to power loss and overheating.
- Clean the Controller: Keep the controller clean and free from dust and debris. Use a dry cloth for cleaning. Do not use liquids.
- Monitor Performance: Regularly check the LCD display for normal operation and expected readings. Note any unusual behavior.
- Battery Health: Ensure your batteries are properly maintained according to their manufacturer's guidelines.
9. Troubleshooting
This section addresses common issues you might encounter with your solar charge controller.
| Problem | Possible Cause | Solution |
|---|---|---|
| Controller not powering on / LCD blank | Battery not connected or reverse polarity; battery voltage too low. | Check battery connections and polarity. Ensure battery voltage is above the minimum operating voltage (typically 8V). |
| Battery not charging | Solar panel not connected or reverse polarity; insufficient sunlight; damaged solar panel or wiring. | Check solar panel connections and polarity. Ensure adequate sunlight. Inspect solar panel and wiring for damage. |
| Load not working | Load not connected or reverse polarity; load current exceeds controller rating; battery voltage too low; load control setting. | Check load connections and polarity. Ensure load current is within 20A. Check battery voltage. Adjust load control settings if a timer or light sensor mode is active. |
| Error codes on LCD | Specific system fault (e.g., overcharge, over-discharge, short circuit). | Refer to the controller's internal error code list (if available in a more detailed manual) or contact HQST support. Address the underlying issue (e.g., reduce load, check battery). |
10. Warranty and Support
For warranty information or technical support, please refer to the official HQST website or contact their customer service directly. Keep your purchase receipt for warranty claims.
HQST is committed to providing high-quality solar products and responsive customer service.
