[Supras] Anyone have any issues with the Exide Sub

[Bill]

Geez, for once I have a possible help for someone ELSE, instead of needing it myself. WOW.

First, I would agree that removing the neg. cable with the engine running isn't a great idea. While you could probably get away with it for a moment or two, the battery helps to keep the electrical system stabilized. There are many comparisons between how electricity and water act. Here's another: A battery acts kind of like the pulsation dampener in your home's water line, helping to subdue any quick, radical changes in electrical pressure. Without it in the line, it's easier to get a dangerous spike.

Another couple of ideas for trouble shooting: Try measuring the voltage at the alternator itself, at idle, with both your meter leads at the alternator....One on output, the other on the case. If there is any significant difference between this reading and the reading at the battery, you have a wiring issue....corrosion, loose connection somewhere, high resistance. The other thing that works once in a great while is to measure output at the alternator on the AC scale. Any more than a volt or so shows one or more bad diodes inside. Time for a new alternator, if that's the case.

Good luck,
Bill