CN3065 Solar Charge Controller
MPPT-style controller for charging batteries from solar panels.
The CN3065 is a compact single-cell Li-ion/LiPo solar charge controller IC that manages the full charge cycle — constant-current bulk charging followed by constant-voltage trickle charging — directly from an unregulated solar panel input. It includes built-in maximum power point tracking-like behavior for small panels, over-charge protection, and thermal regulation, making it a convenient drop-in solution for solar-powered sensor nodes and battery-backed outdoor projects that need to charge safely without a separate charge-management circuit.
Specifications
| Chipset | CN3065 single-cell Li-ion/LiPo solar charge controller IC |
| Input voltage | ~4.4V–6V DC from a small solar panel (panel-dependent) |
| Charge voltage | 4.2V constant-voltage regulation for standard single-cell Li-ion/LiPo |
| Charge current | Programmable via external resistor, typically up to ~800mA-1A depending on board design |
| Charge algorithm | Constant-current / constant-voltage (CC/CV) with automatic trickle-charge for deeply discharged cells |
| Protection features | Over-voltage protection, thermal regulation, reverse-current blocking to prevent battery draining back through the panel at night |
| Status indication | Onboard LED (charging/full) on most breakout modules |
| Interface | Passive power circuit — solar panel in, battery out, no digital interface required |
Pinout
| Pin | Name | Description |
|---|---|---|
| 1 | SOLAR+ | Positive input from the solar panel |
| 2 | SOLAR- | Negative input from the solar panel (often shared with GND) |
| 3 | BAT+ | Positive connection to the single-cell Li-ion/LiPo battery |
| 4 | BAT- | Negative connection to the battery |
| 5 | OUT+ / LOAD | Regulated output to power the project load, present on some breakout variants |
| 6 | GND | Common ground |
This is a single-cell (1S) Li-ion/LiPo controller only — never connect a multi-cell battery pack, as the 4.2V charge voltage will only correctly terminate charging for a single cell. Always match the solar panel's open-circuit voltage to the module's rated input range, since panels rated much higher than ~6V can exceed the IC's absolute maximum input.
Variants
The CN3065 is well suited to small panels (a few watts) feeding a single-cell battery directly. If your panel is larger or efficiency under partial cloud cover matters, the CN3791 offers true MPPT and squeezes more usable charge out of the same panel.
| Variant | Temp range | Hum range | Accuracy | Protocol | Price |
|---|---|---|---|---|---|
| CN3065 breakout module | ~$2-4 | ||||
| TP4056 (with DW01 protection) | ~$1-2 | ||||
| CN3791 (MPPT-style) | ~$5-10 |