|Headlight Relay Tip by George Dockray
I measured the voltage at the headlight to see how much drop there was and hence what improved brightness I could get by installing a relay set-up rather than running all the headlight current through the handlebar switch in the stock set-up. There was about a 1.5 volt drop, so I decided to give the relays a try. I found these Bosch items that fit nicely inside the headlight bucket. An additional 16 gauge power wire was added to a previously unused fuse position to the headlight bucket as well as an additional ground lead (no chance of grounding through the steering head bearings).
The result is a noticeable brighter headlight and should also have greater switch life.
Here's the souce for the Relays.