From my recent regulator experience, I learnt this. The wires the goto the chargeing light, are used as voltage sensing by the regulator, so the voltage at the light goes down, it will compensate for that by charging at a higher voltage. So what can be noticed, is if you put the headlight on, the lights in the cockpit might dim. Then you should check it. What happend at my bike, there was a bad connection in the cabeling. When I put on the light, it draw the current so the charging light got only 9 volt, so the regutator did what it could to get it back at 13 volt, resulting at a battery voltage of 17 volt. I put a new loom in, and now I now have a pretty steady 14 volt voltage with or without light, measured over the battery terminals.