Project Description

The Tiny Solar Power Supply is an ultra-compact, custom-designed PCB that provides a stable, regulated DC output from low-voltage solar panels or small batteries. It is intended for low-power electronics such as IoT sensor nodes, portable microcontroller projects, garden lights, and renewable-energy-based embedded applications.

The design is built around a high-efficiency boost converter IC (AP3015) that steps up a 1–5V input to a regulated 3.3V or 5V output, suitable for powering small electronic loads. An intelligent power-management scheme automatically detects the presence of solar power and prioritizes battery charging when sunlight is available, improving overall efficiency and battery lifespan.

During daylight conditions, solar energy is routed to charge the battery while the boost regulator is disabled to minimize power loss. When solar input is unavailable, the circuit seamlessly enables the regulator to maintain continuous system operation. The board supports common power sources including single-cell Li-ion batteries and compact solar panels.

Key features include a dedicated battery connector, selectable output voltage via feedback resistors, an onboard slide switch for manual power control, and a minimal component count optimized for compact PCB layout. The 2-layer PCB incorporates a solid ground plane, proper inductor thermal handling, and clean routing to ensure reliable performance and manufacturability.

Complete KiCad design files (schematic, PCB layout, 3D models), BOM, and fabrication-ready Gerber files are provided. The project is fully ERC/DRC compliant and released as open-source, making it ideal for educational use, community modification, and real-world solar-powered electronics.