RE: Jetcat ECU Question
I would suggest calling Bob Wilcox at 805-226-8700 to go over what you are seeing, the back and forth online can take forever!
Im my experience, what you are seeing is most likely caused by a bad battery (cell, or a weld), wiring from that battery or a switch (especially the switch). These items can go bad without much warning, especially the switch.
Did I mention a bad switch?!
Good luck in any case, and give Bob a call!