Be advised that this is an experimental setup, it should only be duplicated by those who are familiar with appropriate safety precautions. DO NOT attempt to charge Li-Ion/Polymer batteries with this setup as there is a risk of explosion.
This circuit works by pulsing high voltage short duty cycle spikes, to a problematic battery. This can help breakup sulfation, and re-stimulate the chemistry of the battery. This setup is intended to be used primarily for Lead-Acid, Nickel-Cadmium, & Nickel-Metal-Hydride batteries.
The way this circuit functions is a square wave pulse generated by the Arduino is amplified with a MOSFET to switch an inductor (L1) on and off rapidly. Each time the power to the inductor (L1) is switched off the magnetic field surrounding the coil collapses which generates a high voltage spike. We direct this spike into the charge battery through D1 which allows current to flow in only one direction. D2 is a safety precaution to help protect the MOSFET from being damaged by the high voltage spikes. D3 is a blocking diode to keep supply voltage from coupling with the Arduino's supply. R1 is a pull down resistor to keep the MOSFET off until it receives a positive pulse on the gate.
I used a 12VDC power supply to power the charge circuit. Parts List:
- Q1 = N-Channel MOSFET rated above the input voltage, and for a couple of amps to be safe.
- D1, D2, D3 = 1N4007 Rectifier Diodes
- R1 = 10K 1/2W
- L1 = Experiment with a variety of coils. I used a small air core spool of light gauge magnet wire that measured 15 Ohms.