Originally Posted by JGC EcoDiesel 2014
Improperly cut off LED fog beams? Care to explain what that means Mr. Roadkill sir?
C.f. your own statement: "From time to time I do get flashed but that's just fine."
That's evidence of improper cutoff. If you don't understand the concept of cutoff (especially as it pertains to retrofits), you can google and learn. Proper cutoff really is a safety issue.
Originally Posted by silvermax04
I kinda expect deceptive write ups from bits of junk from no name places in China but a little disappointed to see things written like this from Phillips.
Yes. Furthermore, they tout "no fan" on these bulbs. Unlike incandescent filament-based bulbs (e.g. halogen) that have increased luminous efficiency if the filament temperature is increased, LEDs de-rate when the junctional temperature increases (as discussed in-depth here
). In other words, the hotter the LED is the less light it will produce
. The ~700 lm stat from the OEM is likely measured under best-case circumstances, and the output will be reduced as the LED heats up. Which, you know, it will do while it's turned on—LEDs aren't perfectly efficient at converting electricity to light. To be clear, a fan is not absolutely required (and moving parts are generally undesirable), but the the cooler the LED is the more light it will emit.
I love LED lighting; it's just not there yet for fog/headlamp retrofits. LED tech seems to be following a modified form of Moore's Law
, so in a few generations retrofits will probably achieve legitimate parity with the stock halogens. Watch out for knockoff vendors who claim implausibly high luminous flux (i.e. lumens); a good rule of thumb is that if Philips or Cree have a part that could achieve that efficiency then it *might* be plausible that some random eBay crap could push something similar.
As silvermax pointed out: not even the high-end Philips LED bulbs can match the stock halogens in terms of light output.