LED Lighting

[hycamguy07]

The brake lights on the prius are LED super bright and pull little to no amps ie (0.05amps).

Why wouldn't they use them for the turn signals also they are certainly brighter than the incandecent bulbs and last 100,000 hrs of continous on time???

Cadillac has been using them for a cpl of years as tail/stop/turn signals.

Refletors, manufacturers have made great advances in LED reflector technology and use less LEDs for brighter light.

Other flashlight manufacturers are making flashlights that are LED and produce a purer non blinding light than a ordinary krypton bulb.. ( so inside LED dome lamps coul also be used).

Emergency light manufacturers are even making 360* LED warning lights that even rotate that are DOT approved, and dash/grill/deck lights in LED that are blinding with only 3 LED bulbs and incased in a 4" housing.

I would think this would reserve more energy for the cars electrical system and let you ues more for EV..

Thoughts anyone??

[gschoen]

If Toyota developed LEDs that light using NO AMPS, they're amazing! Creating light from no energy is going to be HUGE.

If they could develop a perpetual motion machine to boot, it would be a great combination.

[hobbit]

I've been looking into the availability of LED-based turn signal
bulb replacements. They're starting to be out there, but there are
a couple of issues. First, few such replacement drop-in modules
are DOT rated, so you probably won't pass inspection with them.
Second, they are not overall as bright as bulbs -- at least not yet.
They may *look* bright if you're standing right in their fairly
narrow beam -- but in the specific case of turn signals, light
*must* also go out to the sides of the car so that people alongside
can tell you're signaling. In other words, a somewhat more
omnidirectional pattern, even though most of it is sent directly
back or front via the reflector. LED units, even the ones that have
a few side-firing emitters, cannot [yet] produce enough lumens to
the side for adequate safety. Brake lights only have to point back.
.
This may change soon, though. In talking just today to Aerometer,
the Sigma Automotive guy, I learned that there's some new and
amazingly bright stuff headed our way from Japan. So there may be
some units available soon which may not be specifically DOT rated
but provide enough light to the sides to act like the lamps. In
the meantime, I'll probably go with some of the "2x brightness"
halogen lamps that are supposedly available now.
.
Oh, a third issue with LEDs is that the Prius' flasher control
doesn't see them as enough of a load, and starts flashing very
fast to warn you that a lamp is out. [remove a bulb and try the
signal to see what I mean.] So that means adding a load resistor.
Which, of course, doesn't save any energy!
.
_H*

[darelldd]

Originally posted by hobbit@Feb 23 2006, 08:01 PM
Second, they are not overall as bright as bulbs -- at least not yet.
They may *look* bright if you're standing right in their fairly
narrow beam -- but in the specific case of turn signals, light
*must* also go out to the sides of the car so that people alongside
can tell you're signaling.  In other words, a somewhat more
omnidirectional pattern, even though most of it is sent directly
back or front via the reflector.  LED units, even the ones that have
a few side-firing emitters, cannot [yet] produce enough lumens to
the side for adequate safety.

Just to be contrary, I'll have to take exception to this. LEDs can very easil produce far more lumens than the incandescent bulbs they are to replace. The total output of light from the bulb is not the issue here. The issue is one of the entire optical system. If the optical system is designed for a incandescent bulb, we do not have a way to make a decent *universal* replacement LED bulb that acts like the factory bulb. It can be brighter, but if the light doesn't bounce off the reflectors the right way, it won't LOOK bright where we need it. If the fixture is designed around LEDs (like the brake lights) then we're off to the races. Brighter, faster-acting and far less current. The difference is in the design, NOT the available lumens.

In talking just today to Aerometer, the Sigma Automotive guy, I learned that there's some new and amazingly bright stuff headed our way from Japan.

The brake lights in the Prius are probably running at about 1W each. Two weeks ago I got to fool with some 10W prototypes, and know that 10, and 50W LEDs will be on the market in 2006. Yes, we'll have some options. There have even been some LED headlights created that can pass DOT. But if you think HID is expensive...

a third issue with LEDs is that the Prius' flasher control
doesn't see them as enough of a load, and starts flashing very
fast to warn you that a lamp is out.  [remove a bulb and try the
signal to see what I mean.]  So that means adding a load resistor.
Which, of course, doesn't save any energy!

Yup. Beyond the optical system not being optimized for LEDs, we have this other stupid issue. Grrr.

[darelldd]

Originally posted by priusguy04@Feb 23 2006, 06:46 PM
The brake lights on the prius are LED super bright and pull little to no amps.

The probably pull on the order of 1/3 the amps of a traditional bulb.

Why wouldn't they use them for the turn signals also they are certainly brighter than the incandecent bulbs and last 100,000 hrs of continous on time???

You got me! And why not use them for interior lighting in a car like this. Makes little sense.

I would think this would reserve more energy for the cars electrical systems...

On the scale of traction power, this energy savings is insignificant. What IS significant is the safety aspects and costs associated with LEDs. Over the life of the vehicle, LEDS would be far less expensive to the consumer. Higher initial cost, but pay somebody to replace just ONE bulb, and you've paid for that initial cost. And then you realize that the LEDs will last the life of the vehicle, and since they are faster-acting, they add a measure of safety for brake and signal lights. They are also more likely to keep working even after a collision since they are solid-state. Designing light fixtures with LEDs also gives the designers much more leeway in offering aerodynamic shapes. The lights can be reconfigured in many different, non-traditional ways.

I REALLY like LEDs, btw.

[KTPhil]

Hi-power amber LEDs have been harder to get at a good price. When our city started replacing incandescent traffic signals with LEDs, they did in stages; first red and green, and then months later, amber.

[darelldd]

Originally posted by KTPhil@Feb 23 2006, 09:27 PM
Hi-power amber LEDs have been harder to get at a good price.  When our city started replacing incandescent traffic signals with LEDs, they did in stages; first red and green, and then months later, amber.

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Interesting. I hadn't heard that about the amber. Reds have always been the best/cheapest out there - even back in the "indicator LED" days. Remember when red was pretty much the ONLY color of LED? The technology is moving so fast, it makes your head spin. The days of ANY incandescent bulbs are numbered. Soon the only they they'll be any good for is hatching chicks.

Incandescent bulbs are quite efficient little heaters. They suck at making light though.

[jbarnhart]

Regarding traffic lights -- it's simple economics. The initial cost of LEDs is higher, but they save a lot of electricity. Red and green lights get a lot of use in traffic lights and burn a lot of watts. Amber gets very little use and contributes very little to energy savings. They also last a lot longer than the red and green incandescent lights because of the light use.

[darelldd]

Originally posted by jbarnhart@Feb 24 2006, 12:32 AM
Regarding traffic lights -- it's simple economics.  The initial cost of LEDs is higher, but they save a lot of electricity.  Red and green lights get a lot of use in traffic lights and burn a lot of watts.  Amber gets very little use and contributes very little to energy savings.  They also last a lot longer than the red and green incandescent lights because of the light use.

[snapback]215775[/snapback]

Quite true! And nobody really responds to the yellow light anyway.

I've heard that the lifetime cost savings are split almost equally between reduced energy consumption and reduced labor to replace burned-out incandescent bulbs (not to mention the safety aspect of same).

[ceric]

LEDs can emit light in all directions. It is called a surface-mount LEDs. They are just not used in automobile yet. Read this link for more technical info.
http://www.fiber-optics.info/articles/LEDs.htm

I also attach a technical HP app-note.
Very good read on this subject.
At 65mph, the faster response time of LEDs (200ms = 0.2sec than regular light bulbs) give you an early response distance of 19 feet. In worse conditions, the difference is even larger. That distance significantly cut down rear-end collision. That is the main reason LEDs are being used as brake light.