You may want to consider this when doing the upgrade. Larger wiring to the relay and light would be optimal. I found this in the sticky about the lights
Hey Guys:
While tinkering tonight in the garage I discovered something very interesting regarding the B-12's headlamp wiring. It is undersized.
Hooking up my volt meter to both the low & high headlight wiring I got a reading of 12.5 volts on either side. (The bike was not running) When I attached the old light units up & took another reading, with the lights in operation, I got 10.5 volts on the low side & 9.2 volts on the high side.
This explains the poor visibility with the stock headlights (black dust aside of course). According to the chart below, if your getting only 70-80% of the voltage required, the brightness of your headlights drops as much as 50%!!!!
I will be installing new wiring & relays with the Hella units.