Thread: $3500 for a pair of spotties What The ?????

I'm running an ALDI winch and have used it in anger a few times with good results. I went from Hella Rallye 2000 lights to Lightforce XGT with halogen bulbs that I got second hand off a Jeep forum (those blokes seem to change their accessories much more frequently than Land Rover owners )
The XGTs are better than the (10 year old ) Rallye 2000s were but not by a staggering degree.
Regards,
Tote

Now these were the ones I was referring to , LED SPOTLIGHT
the add is in the latest Overlander as well, are we sure we are referring to the same lights,Mr Hjelm as there looks like more than 1 parabolic reflector in there !
HELLA RALLYE 4000 LUMINATOR LED SPOTLIGHT METAL 4WD LAMPS | eBay

Hi All,
I'd have to agree with summit. Ive had the rallye 4000's since about 96 and converted them to HID's a few years ago and , like simmit have had them submerged, bashed and vibrated alot and they've never even needed a new bulb yet.
TerryO, I got the same story from the AC tech when I had to replace and over haul my AC system. He claimed that the 4000's reduced airflow by up to 25%. Not sure if there was any science in that number or just 30 yrs experience with AC units.

Originally Posted by Brian Hjelm

Unless you have found a way to repeal the laws of physics, these are far and away the best long range driving lamps available. Remember your Year Twelve Science text books? The maximum output from a light source is achieved by mounting the source at the focal point of a parabolic reflector. The output from a light source increases as the diameter of the reflector is increased.

They are industrial lamps, not automotive and thus have full parabolic reflectors as does the Bosch SL5. They are 250mm and 220 mm diameter. I do not know of any automotive lamps that have full parabolic reflectors or are this diameter. They are normally truncated to limit the distance they protrude from the front of the car.

Check the Hella catalogue for the diagrams of reach and spread.

4000 pencil beam, one lane spread and <700 metres reach.
4000 spread beam, two lane spread at 200 metres and <500 metres reach.
1503 searchlamp, six lanes spread at 300 metres and almost 800 metres reach.

The ideal setup is to have two of them mounted slightly cross-eyed to give an around the corner effect near maximum range. I use 12v 150 watt QH bulbs but there is nothing stopping you fitting an HID conversion if you have a low output alternator.

Define best...

Best "hot spot dot" at their focal point?
Best construction / mount / materials?
Best "usable" beam?
Best value for money?
Best bulb output?

150w means very little without the lumen/watt data...

There are other true Parabolic lights on the market and when it comes to light design for maximum performance there are more ways than "parabola and focal point".

Cibie Super Oscars ? - If they're still in production...

Oscars/super oscars, most all cibies still in production.

Originally Posted by Brian Hjelm

Unless you have found a way to repeal the laws of physics, these are far and away the best long range driving lamps available. Remember your Year Twelve Science text books? The maximum output from a light source is achieved by mounting the source at the focal point of a parabolic reflector. The output from a light source increases as the diameter of the reflector is increased.

Agree, providing all other things being equal, however.

The output of a light is relative to the focal point, depth of the reflector and the light source itself. EG: a large diameter reflector with x mm focal length can have the same captive angle of total light as a smaller reflector with a shorter focal point therefore the same amount of light projected forward.

The light source is relative also, as with different styles of halogen filaments and hid arc lengths there is only a very small portion of the light source at the true focal point. So the rest of the light source forward, backwards and sideways of this theoretical point is actually out of focus which is not projected directly ahead. If it did, the light would look like a laser, not a diverging beam. Therefore a halogen filament will have at least part of its filament passing through the focal point, provided it is mounted centrally. Where as none of a HID arc mounted in a central horizontal position in the reflector is actually at the true focal position because the arc burns in a vertical curve between the arc terminals thereby passing over the top of the theoretical focal point. Therefore the configuration of the light source and the efficacy of the lamp will make a huge difference to output.

Halogen lamps vary from approx 17 lumens per watt to about 40 lumens per watt and HIDs also vary greatly due to manufacturing quality, gas mix, Kelvin and wiring design so it is not as simple as it first appears to make a generalisation about one parameter being all that matters to a lights output.

Originally Posted by Brian Hjelm

They are industrial lamps, not automotive and thus have full parabolic reflectors as does the Bosch SL5. They are 250mm and 220 mm diameter. I do not know of any automotive lamps that have full parabolic reflectors or are this diameter. They are normally truncated to limit the distance they protrude from the front of the car.

Most Auto headlights have some if not all parabolic portions in them and always have been. These headlamps have generally used facetted glass lens to then redirect the light where required.

All driving lights of a “spot” configuration use a parabolic reflector or you would not get a spot. This includes the old style OEM Lucas sealed beams with clear glass lens (Jaguar and others).

In recent times the auto industry has moved on some auto models to “freeform” reflectors to change the direction of some of the light beam instead of using facetted lenses. The other change is to projector type lens to reduce bonnet height, therefore better vehicle aero dynamics.

It is worth noting also that in the absolute sense it would be difficult to find a true parabolic reflector in lighting due to the reflectors being made of materials that have inherent shrinkages and stresses induced during processing (EG: Plastic, spun alloy, castings etc) that once removed the finished product changes to something not exactly the same as the forming tools which may be in themselves perfect parobolas. But they are generally close enough for the purpose.

Originally Posted by Brian Hjelm

Check the Hella catalogue for the diagrams of reach and spread.

4000 pencil beam, one lane spread and <700 metres reach.
4000 spread beam, two lane spread at 200 metres and <500 metres reach.
1503 searchlamp, six lanes spread at 300 metres and almost 800 metres reach.

The ideal setup is to have two of them mounted slightly cross-eyed to give an around the corner effect near maximum range. I use 12v 150 watt QH bulbs but there is nothing stopping you fitting an HID conversion if you have a low output alternator.

Out of curiosity, what P/N are the 12v x 150 watt QH globes you are using?

cheers
Tombie

Brian.... Can you provide the part number for the 150W globes you're using?

Any feedback on my response?

I'm keen to hear your views