CN3791 12V MPPT Solar Charger Module
CN3791 12V MPPT Solar Charger Module
Maximum Power Point Tracking Solar Charge Controller for Lead-Acid/Lithium Batteries
Introduction
The CN3791 MPPT Solar Charger is an efficient power management module featuring Maximum Power Point Tracking technology. It’s designed for 12V battery systems with solar panel inputs up to 28V, providing optimal charging for lead-acid or lithium batteries.
CN3791 MPPT Solar Charger Module (Image source: Imgur)
Key Features
MPPT Technology
>95% tracking efficiency
Multi-Chemistry
Supports Li-ion/Pb batteries
High Current
Up to 5A charging current
Full Protection
Overcharge/reverse polarity
Technical Specifications
| Solar Input Voltage | 6V-28V (Max 30V) |
|---|---|
| Battery Voltage | 12V (adjustable 10-14V) |
| Max Charging Current | 5A (with heatsink) |
| MPPT Efficiency | >95% |
| Standby Current | <2mA |
| Charging Accuracy | ±1.5% |
| Operating Temp | -40°C to +85°C |
| Dimensions | 56mm × 42mm × 14mm |
Pin Configuration
Pinout diagram (Image source: Imgur)
| Terminal | Function | Description |
|---|---|---|
| SOLAR+/- | Solar Input | Connect to solar panel |
| BAT+/- | Battery Output | Connect to 12V battery |
| LOAD+/- | Load Output | Optional DC load |
| USB | 5V Output | 500mA max |
Typical Wiring Diagram
Typical installation wiring (Image source: Imgur)
|
1 2 3 4 5 6 7 |
// Connection Guide: // SOLAR+ → Solar panel positive // SOLAR- → Solar panel negative // BAT+ → Battery positive // BAT- → Battery negative // LOAD → Optional DC load // USB → 5V output port |
Battery Voltage Adjustment
Adjusting the voltage potentiometer (Image source: Imgur)
- Locate the blue potentiometer on the board
- Connect multimeter to BAT+ and BAT-
- Turn clockwise to increase voltage (max 14.4V for lead-acid)
- Turn counter-clockwise to decrease voltage
- Set according to battery specs:
- Lead-acid: 13.8V-14.4V
- LiFePO4: 13.6V-14.0V
- Li-ion: 12.6V (3S)
Charging Status Indicators
Red LED
Solid: Charging in progress
Blinking: Battery full/float charging
Green LED
On: Solar input detected
Off: No solar power
Blue LED
On: Load output active
Off: Load disconnected
Troubleshooting
No Charging
- Verify solar panel voltage > battery voltage
- Check polarity of all connections
- Ensure battery isn’t fully charged
Overheating
- Reduce charging current
- Add heatsink to IC
- Ensure adequate ventilation
Low Efficiency
- Check solar panel alignment
- Verify battery voltage setting
- Inspect for voltage drops in wiring
Application Examples
Solar Lighting
Street lights/garden lights
RV Power System
Mobile solar power
Remote Monitoring
Weather stations/cameras
