As an aternative with a difference...for you guys that love to play with something completely different.
Ex colleague of mine had a fibre optic cable running from his rear light to the computer.
Three advantages.
No battery drain.
Computers lit all the time the lights on.
You have an indication that your rear light is actually on.
Its quite easy to do and ony needs a few tyraps to fix it in place.
The downside..he drilled a hole in the light to point the F/optic cable at the LED (for maximum light) then sealed the hole with some clear silicone. Some would not want to do this....
A simple wire bracket was made to point the pointy end of the cable at the computer, f/o cable affixed to the bracket with tyraps.
Its possible to do it with the front light....maybe better that way.
It sounds a bit heath robinson, but he did a damn good job of it. Very effective.