Restoring old and dying batteries to extend their life is possible with a simple homemade circuit. This article will provide a step-by-step guide on how to build such a circuit using basic electronic components.

What You Will Need

To build the battery restoring circuit, you will need the following components:

How the Circuit Works

The LM317 voltage regulator steps down the 12V input to the required voltage for charging the battery. The 2N3055 power transistor acts like a switch, controlling the current flow to the battery.

The 1k resistor is used to set the output voltage. The LED provides a visual indicator when charging is in progress.

This simple circuit restores batteries by providing a controlled charging current to deeply discharge batteries. The process removes sulfation and extends battery life.

Building the Circuit

Step 1: Insert the LM317 voltage regulator into the breadboard. The input pin goes into the positive rail and the GND pin to the negative rail.

Step 2: Connect the 1k ohm resistor from the output pin to the negative rail. This sets the output to around 3.3V.

Step 3: Connect the 2N3055 transistor with the collector to the positive rail and emitter to the regulator output. The base goes to ground through a 1k resistor.

Step 4: Connect the LED and switch in series to the emitter of the transistor.

Step 5: Connect the battery holder positive terminal to the emitter of the transistor before the LED. The negative terminal goes to ground.

Step 6: Connect the 12V input to the input pin of LM317.

Charging Old Batteries

To charge old or dying batteries with the circuit:

Tips for Best Results


Restoring lifeless batteries is possible with this simple homemade charger circuit. It removes sulfation buildup and revives old batteries for extended life. You can now avoid replacing batteries frequently and reduce electronic waste. Just follow the instructions to build the circuit and start reconditioning old batteries! Let me know in the comments if you found this tutorial helpful.