AA Solar Battery Charger
This simple solar battery charger is designed to charge AA rechargeable batteries using a small solar panel. It uses a 1N5848 Schottky diode to prevent reverse current flow from the battery to the solar cell at night.
Solar Panel
- Solar cells with 0.5 V, 50 mA output each.
- Cells can be connected in series to match the required charging voltage for AA batteries (~1.2 V per NiMH cell).
Circuit Operation
- The solar cells generate DC voltage when exposed to sunlight.
- The 1N5848 Schottky diode allows current to flow into the battery while preventing backflow.
- The battery charges slowly and safely with low current, suitable for trickle charging.
Key Features
- Charges AA NiMH or NiCd rechargeable batteries using solar power
- Schottky diode (1N5848) prevents reverse current at night
- Simple and compact design
- Low current trickle charging ensures battery safety
- Eco-friendly, solar-powered operation
Construction Notes
- Connect enough solar cells in series to exceed the battery voltage slightly for proper charging.
- Ensure correct diode orientation — the cathode goes to the positive battery terminal.
- Use a small enclosure to protect the solar panel and battery from weather if used outdoors.
- Optional: add a small resistor (10–50 Ω) in series with the battery to limit charging current.
| Component | SKU | Type |
|---|---|---|
| D1 | 1N5848 | Schotty |
| SC1-SC8 | Solar Cell | 0.5V - 50mA |
| 1 full day to complete AA charge | ||
| 1/2 day to complete AAA charge | ||