Wednesday, Feb 6 2019 [9,882 miles]

Because I want as much power possible for heated gear and grips I’m changing the tail light and the license plate light to LEDs. I changed the head lamp to LED back in 2015. My plan is to measure the current draw before and after change. Plans don’t always work out.

I started with the license plate bulb. Unfortunately I dropped the bulb while trying to hold bulb and probe to reach the contact pins without shorting to ground when measuring the current. That broke the filament. So I don’t know how many milliamps the stock bulb actually pulled.

The replacement bulb pulls about 44 mA. That’s about .6 watts. Specs for the stock bulb say it will typically draw up to 5 watts.

I was able to measure the draw of the stock tail light, but not when braking. I ran out of fingers, hands and didn’t have long enough legs to hold everything together while triggering the brake light. The stock bulb pulled 430 mA. The replacement pulls 90 mA. That’s about 6 watts stock (assuming 14 V when the bike is running, might be less) vs 1 1/4 watt with the LED bulb.

It looks like I lost 9 watts worth of lighting draw. That’s 9 extra watts for heated gear and grips. Not a lot, but every little bit helps.