Why does my Dyna S spark continuously when I am charging the battery? Matt May 23, 2018 18:28 Follow Battery chargers constantly switch between high and low voltage. The Dyna S see’s this as the ignition being switched on and off resulting in the constant spark described above. Related articles Dynatek Warranty What coils should I use? What spark plugs should I use? How to configure dyno for use. Comments 0 comments Please sign in to leave a comment.