In the "brightest light for under $200 thread" we were discussion limitations of certain kinds
of light. I'm going to discuss something that apparently effects both HID and halogen lights
(and probably not LED, *YET*).
In that thread, a discussion on how HID lights typically require forward motion lest the lamp
overheat was discussed. I know in my particular system (Trailtech Eclipse 13w) the manual
says that if the light overheats it will shut off by itself to protect itself. I've not actually
experienced this behavior though even though in commuting I've stopped at stoplights for
minutes at a time with the light going.
Consequences of running it as a camping light, or "impress your friends at your party with
the incredible brilliance without a fan blowing at it" = shorter bulb life probably.
I also read on the net a person who ran their HID for extended periods without
forward movement caused the epoxy adhesive that kept the glass lens in place
vaporized due to the heat, settled on the reflector for the bulb and the light
quality significantly degraded.
They had to find a way of using a cotton swab with electronics grade alcohol
to polish the reflector and light quality improved but I suspect this is a very
rare situation on very particular lighting systems.
I also noticed in the manual for my wife's Niterider Classic Select (a 25 watt
dual beam halogen system) it cautions very strictly about not running the lights
for extended periods without forward motion to cool the lamps lest the bulbs
get exposed to high levels of heat which can shorten their service life
significantly or cause them to fail altogether.
Obviously, halogen and HID headlight systems for automotive applications
have been in use for years. Cars often idle with headlights running and do
not experience these issues.
My feeling is that the small housings for bicycle headlights lend themselves
to the potential of high temperatures but I am pondering if some of these
warnings were aimed at people who would stop for extended periods with
their lights blazing or weren't cycling at all and were using them as camping
lights or "flamethrower flashlights". I remember at least one post at mtbr.com
where a rider left their nightrider light/battery connected in his bike bag and
it caused a rather significant fire in the riders automobile.
Thinking about the new generation of high powered LEDs I ponder if this issue
won't be in effect there as well. I ran two Cateye EL300s and left those things
on for hours with no problem whatesoever. But with the new SSC and Cree LEDs
and some of them being run in multiple combinations in the same housing (Trinewt,
TridenX) some of the same issues could occur I surmise.
Has anyone really run into issues with this? I suspect these warnings just end
up making the potential purchaser freak out unnecessarily. I know of one
rider who commuted with a Cateye Stadium III HID for six years and had no problems of this kind.