Headlamps

[wh500special 2,055]

I apologize if I seemed rude...

I didn't read it that way. So no apology needed!

We ran into some heating issues with LED's at work and it really caught me by surprise since we all "knew" how much PR has been given to them as being our salvation from incandescnat heat lamps.

One of our EE's bought a handful of LED "pucks" that were 8 or 9 watters to use for general lighting in one of our products. Long story short, we were all surprised to see the warnings given in the instructions that the lamps must be mounted to a metal chassis or heatsinked with finned sinks so they didn't overheat.

Sure enough, plug 'em in and they get incredibly hot unless solidly affixed to something that can draw heat from them. It was just counterintuitive.

Thus started the interest in them. None of us ever gave them any thought up to that point. Since they were intended for a tent and we had no structure to heat sink them on, we had to go with fluorescent which ends up being the most energy efficient alternative anyway for general lighting applications.

I keep waiting for the UV LED's that will work for fluorescent lamps. It's coming, and THAT will be a huge advancement for lighting efficiency.

Somewhere on this computer I saved some links to articles about designing heat sinks for LED's and where they do and don't make sense. If I find them I'll send 'em your way.

Steve

[Sarge 3,462]

Well, as long as we're learning here...what about the little LED strobe/clearance marker lights ? I'm curious to what their amp draw would be and how they can attain a low wattage draw with the associated firing voltage? Thought about an amber one for the rear of the plow tractor for safety.

Sarge

[MikesRJ 552]

This strobe: http://order.waytekwire.com/productdetail2...LIGHT%20YELLOW/ only draws 0.15 amps. The lights internal capacitance (power storage) is what fires the lights.

Kind of like filling a bucket with a garden hose, then dumping the bucket all at once. The flow of water (current) is consistent and doesn't change over time, and how fast you fill (how much current), regulates the period of the fill the bucket and it dumps (flash).

If you have a particular light in mind, post a link to it.

[Sarge 3,462]

Somewhere I've seen some clearance size lights that have either a blinking LED array or strobe, now nowhere to be found , .

The ones I'm looking for are the same size/type as the rear tail light on my C-series.

Sarge

[MikesRJ 552]

I've seen strobing turn signals (similar to ">>>>" ) where they strobe with arrows. In fact I think they have them on the Super-Bright site.

UPDATE: http://www.hyper-lights.com/index.php?cPath=22_27 Like these? (only 0.4-0.8 Amps too!)

None of the following applies when using the LED lights above:

Keep in mind that all of the LED lights can be flashed using a standard LED flasher unit just like a cars turn signals. Simple to do really, the flasher unit goes in-line with the power (12-13.5 vDC) to the lights and can be wired like the graphic below.

The graphic shows an incandescent light, but the LED circuit is identical except the LED and Flasher parts replace the incandescent lights and incandescent flasher unit.

1. The circuit shows the tractor battery power feeding the ignition switch.

2. The ignition switch feeds 12v power to both the headlight and the center contact of the "flasher switch".

3. With the Flasher switch in the "OFF" position (as shown), power is fed to the lights directly, and the tail lights remain constantly "on".

4. Flick the switch, and power is routed through the switch to the flasher unit; from the flasher unit to the LED's; and the LED's will flash at the designed rate of the flasher unit (normally 60-120 flashes per minute for turn signals).

[Sarge 3,462]

Bingo! That's exactly what I had in mind, thanks !

Kudos on the diagram as well, forgot about wiring them for standard/flash display.

Sarge

[Save Old Iron 1,563]

...and those of us sitting ringside to this little debate are not only enjoying it, but also learning a whole lot as we go!

[Save Old Iron 1,563]

None of the following applies when using the LED lights above:

Keep in mind that all of the LED lights can be flashed using a standard LED flasher unit just like a cars turn signals. Simple to do really, the flasher unit goes in-line with the power (12-13.5 vDC) to the lights and can be wired like the graphic below.

The graphic shows an incandescent light, but the LED circuit is identical except the LED and Flasher parts replace the incandescent lights and incandescent flasher unit.

Careful here too. Mike had mentioned this but it really needs to be EMPHASIZED - if you are flashing LED's then you need an LED FLASHER device - not an older mechanical flasher.

Not all automotive flashers are applicable to LEDS. The current flow thru some flashers determines their flash rate - as when a single tail light burns out - some flashers will cycle much faster alerting the driver to a failed tail light filament. So using an LED device with this style flasher may not work well or may not work at all due to the significant decrease in current going thru the flasher device.

Just a tip for all the grumpy old men like me who like to play with rusty old tractors. :thumbs:

[MikesRJ 552]

Agreed, What SOI said!

[HankB 16]

Guys,

...

The auto exposure settings of modern cameras are very good at "averaging out" the brightness of a scene to give the best possible exposure in a given circumstance.

...

A valid comparison would be to set your camera on manual exposure and record the brightness of the lamp on a garage door or wall - STANDING BEHIND THE TRACTOR.

or

better yet - place one incandescent bulb in one headlight bucket, an LED in the second bucket and shine both thru the same lens - same tractor battery voltage - same wall - same camera setting - you get the idea.

What he said.

I'll add that I found out quote accidentally that something that throws a shadow will hilight the difference. I replaced one backup light bulb in my truck with the capsule from a higher wattage fog light bulb and backed the truck up to a light colored garage door. While walking between the truck and door, I was struck by how different the shadow looked so I put something centered between the lights to demonstrate this. You can see the results below:

One shadow is easily visible while the other is almost completely washed out by the brighter bulb.

[MikesRJ 552]

That said, and I do agree with you in theory, this test is accurate and useful only when the lights under test are parallel to the projection surface (garage door in this case); the shadow objects (blue pails in this case) are directly between the lights and projection surface; and the shadow objects are at identical distances from the projection surface.

In your picture the buckets are a little different in position away from the door, the left bucket being further away from the door than the right bucket. This condition makes the left shadow larger and more diffused than on the right. Both lights must have the same set of conditions in order to compare apples to apples.

JMHO!

[HankB 16]

That said, and I do agree with you in theory, this test is accurate and useful only when the lights under test are parallel to the projection surface (garage door in this case); the shadow objects (blue pails in this case) are directly between the lights and projection surface; and the shadow objects are at identical distances from the projection surface.

In your picture the buckets are a little different in position away from the door, the left bucket being further away from the door than the right bucket. This condition makes the left shadow larger and more diffused than on the right. Both lights must have the same set of conditions in order to compare apples to apples.

JMHO!

Ignore that barrel behind curtains!

Had I been more energetic, I would have moved it totally out of the frame. The barrel in the middle is centered off the tailgate and the tailgate is pretty close to parallel to the door. If you look carefully, you can see the top edge of the tailgate along the bottom edge of the photo. There is a shadow on either side of the barrel centered in the picture.

Apologies for the confusion.

[kajamo240 3]

That said, and I do agree with you in theory, this test is accurate and useful only when the lights under test are parallel to the projection surface (garage door in this case); the

[HankB 16]

I'll circle the shadows. The one on the right really is subtle.

These are two different incandescent bulbs. The factory bulb (on the right in the picture) is an 18 watt 921 and the replacement is a 27 watt 889 fog light bulb modified to fit.

I hope you can see that now. I need to retake that picture without that extraneous clutter.

[Save Old Iron 1,563]

well done - clean up the clutter and confusion

and now for a little photshop magic, this is safe to do at home boys and girls.

I loaded the photo into an image editor - pressed the decrease brightness setting until the image of the left of the screen just disappeared

the result is the "difference" between the brighter bulb and the dimmer bulb - not really all that much

this is still a flawed experiment but when you subtract one bulb from the other to get an overall difference

this is what's left

also realize the dispersion pattern of these two bulbs may not be the exactly the same and one bulb may "bleed" into the others pattern due to the differences - spot vs flood effect, etc.

update - well I looked a this image on my LCD monitor when I posted it - I could see the residual difference - I now just looked at the same image on my older CRT monitor and see an almost totally black image !! trust me - either way - there is not too much real difference in the brightness on the photo

maybe you have to be there in person to tell. I t might be just one of those things :thumbs: