[ale] More on LEDs...

[Ken Cochran]

Replying to 2 messages, see comments interspersed...  -kc

> From: "Ron Frazier (ALE)" <atllinuxenthinfo at techstarship.com>
> Date: Fri, 16 Aug 2013 22:38:33 -0400
> To: neal at mnopltd.com, Atlanta Linux Enthusiasts <ale at ale.org>
> Subject: Re: [ale] More on LEDs...
>
> Hi Neal,
>
> I didn't know that.  Very interesting.  Sounds like faulty lamp driver
> design to me, although they obviously want to prevent massive overloads.
> However, leds should only pull about 1/5 the wattage of a standard bulb,
> so hopefully the ecu will be happy.
>
> Sincerely,
>
> Ron

Not so much "faulty" lamp driver design, but design for a
specific load (I guess), for example, in support of bulb
failure notification at the instrument panel.

> Neal Rhodes <neal at mnopltd.com> wrote:
>
> >Attempting to steer the off-topic at least back to the concept of
> >computers.........
> >
> >Actually one should be somewhat careful regarding messing with
> >tail-lights - it could stop your engine.    No, I kid you not.
> >
> >If you go the other direction - bulbs which draw MORE power - you can
> >risk a scenario where you are pulling more amperage and you drop the ECU
> >(there, I said computer) voltage below what is expected to run the engine.
> >
> >Classic example is hooking up a trailer with lights to your car.
> >
> >Stock Sprinters are known to quit running when this is done.

Yeah, I could believe that with Sprinter - that's Mercedes-Benz...

> >Winnebago actually puts a relay on the brake light circuit, and runs the
> >rear brake lights (and trailer lights if connected) off the relay,
> >rather than risk sucking too much draw off the ECU circuits.
> >
> >Moral: you mess with the fragile compooooter in your car at your own peril.
> >
> >On Fri, 2013-08-16 at 15:10 -0400, Ron Frazier (ALE) wrote:
> >
> >> Hi all,
> >>
> >> I'm learning more about what you can, and cannot do with leds.  I
> >discovered the tail light in my car was out.  The car is a Hyundai
> >Santa Fe compact suv.  It has a combined brake light and tail light
> >which uses a dual filament bulb, an 1157.  I found the 1157R led bulb
> >at autozone and put it in the car.  The bulb was barely visible at all
> >when the brake pedal was pushed, although it did turn on.

At least as apply to Mercedes-Benz & Volkswagen:  Never had
one shut down on a bad bulb but these makes require a specific
(almost vendor-specific) bulbs.  A 1157, etc., will "work" and
will (might) shut off the instrument panel warning light but
you'll get erratic (demon-possessed even) behavior of various
vehicle systems (e.g. climate control, cruise control) if you
don't use the correct specific (European spec) replacement bulb.
This goes back decades, applying (maybe especially) to the
old "analog" electrical systems, as well as the more modern
computer-controlled ones.

[... snip ...]
>
> --
>
> Ron Frazier
> 770-205-9422 (O)   Leave a message.
> linuxdude AT techstarship.com
> _______________________________________________
>
> From: "Ron Frazier (ALE)" <atllinuxenthinfo at techstarship.com>
> Date: Fri, 16 Aug 2013 22:41:32 -0400
> To: Atlanta Linux Enthusiasts <ale at ale.org>
> Subject: Re: [ale] More on LEDs...
>
> William Bagwell <rb211 at tds.net> wrote:
>
> >On Friday 16 August 2013, Ron Frazier (ALE) wrote:
> >> It has a combined brake light and tail light which uses a dual filament
> >> bulb, an 1157. Â I found the 1157R led bulb at autozone and put it in the
> >> car.
> >
> >Ah, was not aware they were making retrofit LEDs! Will look next time I'm in
> >a parts store for LED tag lights. Unlikely to have the lensing problem you
> >noted with tail lights so the longer life (and gradual failure if the
> >individual LEDs do not fail at the same time) would make this an ideal
> >application.
> >
> >Anyone who drives an older car at night will know why this is important:)
> >--
> >William
> >
>
> Hi William,
>
> The auto parts stores have a pitiful selection.  See my reply to Adrya
> for a number of other sources.

Parts stores I trade with here in Alabama no longer carry
LED replacement bulbs.  Reason (they told me):  Illegal, not
compliant with DOT/DPS regulations.  They are only legal when
the fixture (e.g. the light assembly itself) came originally as
LED.  So you CAN get (& they stock & sell) LED light *fixtures*
(e.g. trailer lights) but no LED replacement bulbs, say, to
replace a 1157.  Actually makes some sense to me because of
such things as the focus difference in a lamp/reflector/lens
assembly, as well as the (apparently calibrated) load difference
that would occur in a modern vehicle electrical system.

[... snip ...]
>
> Sincerely,
>
> Ron
>
> --
>
> Ron Frazier
> 770-205-9422 (O)   Leave a message.
> linuxdude AT techstarship.com