Carbon/Carbon rechargeable cell
An improved cell here, which is also much closer to a true Karpen Pile.
2 types of carbon – the inner core from a dead AA battery and a piece of BBQ charcoal (which is years old and well rain washed, having sat in a disused grill outside).
Electrolyte is approx 8 parts sea salt, 1 part Moreton Salt Substitute and 1 part alum + rainwater.
It has a relatively strong initial charge, 100mV being the usual for carbon Karpen cells. It’s rechargeable and has an output in the milliamps, rather than microamps.
The charger used, is an Electrifly R/C unit, set at 200mA which is the lowest setting. After 2 minutes, the bubbles made me wonder about gasses building up, so it was disconnected.
Thanks to Steve Allwest for his mention about iron particles in some ferrites – which was why I changed to Carbon/Carbon for this cell.