A Duracell D - cell battery goes up in flames after being overcharged at 36 Volts AC.
Flames are vented out of the cell like little flame throwers.
The power transformator set up is shown at the end with two transfomators and switching arrangement to have individual switching for primary TX excitation in parrallel and secondary load in series to increase the voltage.

Safety: minimum PPE at least safety glasses to be worn and a glass shield used between operator / camera and test cell.