This was a modification (something of a daughter board) to the venerable Heart InCharge Regulator, where I replaced the manual charge setpoint potentiometer with a digital version, controlled by the Arduino. I added a thermocouple and hall-effect current sensor for feedback. At this time, I was intimidated by the prospect of creating a regulator from scratch, and this was an effective temporary solution.
Here are some more photos of the InCharge, because I like the design. It was a high-end product in its day, with a thick PCB, clean layout, conformal coating, and a probably well-protected circuit. I have several of these from the 90’s and they’re still going strong.
