Most 12 volt coils have an internal resister. I learned the expensive way that voltage control is extremely important when using an electronic ignition module, especially if you have an off-shore made alternator. I found that most were coming from China and their internal diodes were not trustworthy. So if new I took them to a local electric shop for testing. The majority, regardless of the seller, were faulty. I added a voltage gauge in my set up. Pretty much any voltage SPIKE above 14.5 volts can kill a module. Also, as Pentronic's told me, low voltage can harm a module too. Jim Lindner, unfortunately no longer with us, was an expert re modules and said a friend of his mounted a standard generator control box on his alternator to better control its output.
