Lead-Acid Battery Charger with LM317
This simple DC battery charger is designed for 12V lead-acid batteries using the LM317 adjustable voltage regulator. It allows safe and controlled charging with adjustable current.
Circuit Operation
- The LM317 regulates the output voltage to safely charge a 12V battery.
- A 1 kΩ potentiometer allows adjustment of the charging current. The recommended charging current is approximately 1/10 of the battery's Ah rating.
- The input voltage on pin 3 of the LM317 should be at least 15V DC to ensure proper 12V output for battery charging.
- A heatsink is required on the LM317 to dissipate heat generated during charging.
Key Features
- Adjustable current charging for 12V lead-acid batteries
- LM317 regulator for stable output voltage
- Potentiometer allows precise current setting based on battery capacity
- Simple, compact, and reliable design
Construction Notes
- Use a proper heatsink on the LM317 to prevent overheating.
- Ensure the DC input voltage is at least 15V for correct 12V charging.
- Monitor battery voltage during initial testing to verify proper operation.
- Keep wiring short and use sufficiently thick conductors to handle the charging current.
