Headlamp Upgrade

[raymr]

I put the additional relay in the headlamp shell and ran a dedicated power wire to it from the OEM relay under the gas tank, as well as a ground. Now all the headlamp switch does is activate the relay for high beam. It makes a neat little click whenever I operate it.

When I looked things over, I discovered that there is no fuse protection for the headlamp circuit at all. That will be fixed soon.

[bruce_launceston]

When using a relay it would be better to have the relay as close as possible to the battery and run a min 30 amp cable and fuse to the relay, use the old power feed to the headlight as the switch wire to activate the relay and run decent size cables for power and earth to the headlight bulb.

This did wonders for the lighting on an old Guzzi V65 that we owned, the OEM wiring was tiny.

I have rewired my high and low beams through 2 relays on my R65 with barely noticable improvement.

I would also like to know if anyone has removed the bulb shield/reflector and what the result was.

[Barry]

My initial reaction to the last two posts was the relay should be as close to the headlight as possible but actually given equal cable sizes both positions can give the same result.

Putting a relay anywhere along the route of  properly sized cables to the headlamp bulb should effect a reduction in voltage drop and therefore improve the light output. The current has to get all the way from the battery to the bulb wherever the relay is so if the relay feed cables and output cables to the headlamp are properly sized it doesn't matter where the relay is located as ohms law tells us that if the total cable length is the same then the voltage drop will be the same.

I'd mount it in the position that provides the shortest overall cable run and where it's most convenient to pick up the output from the light switch.

It would be quite easy to measure the voltage drop using the stock wiring and then calculate what reduction in voltage drop would occur with larger cables and a relay. From that you can then estimate what percentage improvement in light output would be achieved.

If someone tells me the cable length and size they are proposing to use I could do the calculations.