Increasing Brigitta's Tailight's Lumen Output

Brigitta, my 1987 R80 Beemer, came into my possession with a 5 watt tail light bulb. It was dim, it's light hardly visible in bright sunlight, at least to me while standing 10-20 feet to the rear of the motorcycle.

The tail light with the 5W Bulb, afternoon sun hitting the rear of the motorcycle directly

As a stopgap, I mounted an 12 LED stoplight, wired to be on continuously while the ignition was on. I felt safer.

Recently, half of the LEDs quit working and so I revisited the light output limitations on the R80.

Yesterday, I replaced the taillight bulb with a Sylvania Type 97 13.5V 9.3W bulb from the auto parts store. The light was yellower but seemed to be a bit brighter with the red plastic taillight housing back on.

Today, I rolled Brigitta out on the cul-de-sac, walked back about 20 ft and was disappointed with the perceived light output of the new bulb. Off to the auto parts store again, did some more looking around and found a Sylvania Type 105 12.8V 12.8W bulb.

I replaced the 9.3W with the 12.8W and was pleased to see I could actually see the tail light illuminated from 20 feet away. My only remaining concern now is heat output from this new bulb, will have to monitor over time.

The tail light with the 12.8w bulb, I could see a difference with my eyes, my camera...not so much

Did some research to validate my assumption that more wattage = more light output.

I found the following excerpt on ehow.com: Wattage is the amount of electricity needed to light the bulb. The higher the wattage is, the brighter the light will be. LINK

Another link stated incandescent bulbs put out 7-24 Lumens per Watt. Which if you do the math, it boils down to more watts = more lumens = more perceived light.

So, taking the arbitrary value of 7 from the above statement, my original 5W bulb was putting out 35 Lumens, my new 12.8W bulb is probably putting out 89.6 Lumens. So about 2.56 times more light!

No computers, local area networks or fancy electronics on the airhead, so I don't think introducing this higher wattage bulb will affect anything on Brigitta except a bit more power drain which I'll monitor via the voltmeter.