Wires going to + of coil

Now this post may be only "coffee talk" and not apply here but I'll share it anyway. Keep in mind this was way before internet. Auto Zone was Auto Shack.
The owner attempting to upgrade the charging system. Needing additional 12 volt wire to energize the alternator field. Just looking under the hood he had conceived that the closest simplest add-on point was the + side of the coil.
Since the coil doesn't get full 12 volts in run, his result was downgraded charging system.