Originally Posted by JAFO
As with all vehicles with an alternator, the alternator runs the bike and charges the battery.
The battery is only there for starting the bike.
He's got a point, though. The extra light (if they both indeed run simultaneously) will draw more of the alternator's output.
The addition of just one light should
be fine, but not much else I don't think.
I've killed my battery a couple times running extra lighting, but that was 2, not just 1 additional.