I commute with a NR Flamethrower HID headlight, and last year added a strobe taillight [allelectronics, Velleman] for use in the fog, wired into the NR's battery. Midwinter I had to send the NR in for service, and among other things they replaced the ballast. The Velleman is rated at only 150 mA, but it still must produce some degree of voltage spike in the lines; is there any way that stray spikes of that size could cause damage to the ballast of a HID light? Would it be enough of a problem that I would need separate batteries or some sort of surge protector? Am I being paranoid over mere coincidence?