LED
Light-Emitting-Diodes

The efficiency of an illuminant is determined by the ratio of accepting energy to yielding luminous flux.
The unit of measurement is lumen per watt (lm/W).

Below are listed some comparative values for common illuminants in the order of their efficiency
(Issue 01.2008)

Illuminant	lm/W
Light bulb	approx. 15 lm/W
Halogen bulb (do-it-yourself store)	approx. 25 lm/W
Cold-beam bulb	approx. 30 lm/W
Halogen bulb HLX	approx. 35 lm/W
White LED (Light-Emitting-Diode) *	approx. 55 lm/W
21/24W Brightstar HID lamp	approx. 60 lm/W
Energy-saving lamp	approx. 65 lm/W
Fluorescent lamp	approx. 80 lm/W
D2 gas discharge lamp ( HID)	approx. 90 lm/W

*The data given above is the actual light emission from a lamp under practical subaquatic conditions/cooling and continuous operation.

The data given by the manufacturers of LEDs (e.g. 100 lm/W) is based on laboratory tests at a maximum temperature of 25°C and is achieved for a fraction of a second. The operation is however actually performed at approx. one third of the maximum power output. If more power is provided to the LED as is the case in practical use, the resulting amount of light per watt (lm/W) actually decreases.

Unfortunately, most manufacturers of underwater lamps simply copy these non-field performance data in their technical data sheets.

Since the beginning of 2008 Hartenberger has incorporated the latest generation of LEDs in our products and these far exceed the efficiency of halogen bulbs even under field conditions. LEDs are being continuously improved and although the research has slowed down to some extent.
LEDs with a performance that match gas discharge bulbs will probably be available in the near future.
We can assure our customers that we will use the most effective and efficient light elements available on the market in our products and combine these with the optimum conditions and monitoring (cooling and electronic controls).

Any energy that is put into a bulb or LED is only partially converted into light, the rest is converted into heat. Therefore the LEDs produced currently only generate slightly less heat than the most efficient halogen bulb. (based on information available in Jan. 2008). The claims of some dealers of LED lights is therefore uncomprehendable to us.
The majority of the heat that is yielded by halogen bulbs is emitted forwards through the reflector. Therefore, the beam is relatively warm. However, the beam of an LED is almost cold. Therefore, the complete heat of the light-producing semiconductor has to be dissipated "backwards" through the printed circuit board / cooling surface.

In order not to destroy a high-power LED it should only be operated for a few seconds without adequate heat-dissipation / cooling.
These circumstances demand an increased constructive effort in order to ensure the necessary heat-dissipation / cooling.

An overload protection prevents excessive overheating of the high-power LED if cooled down badly, and lowers the power consumption.

LEDs do not produce a balanced colour spectrum of light. The red colour is very poorly generated. The colour temperature of white LEDs is approx. 6000K.

Your can find more information and descriptions about our LED modules under LED-Technology (LED-Technics)

HID
High-Intensity-Discharge

The colours spectrum from gas discharge elements (HID - High Intensity Discharge) perform very similar to the LED.
Compared to our high performance HLX halogen bulb, the efficiency is approx 2-3 times better (see the comparison table for standard light elements). We use a 35W gas discharge element common in the auto industry in our Mega D2 lamp. The lamp has a colour temperature of approx. 4600K.

 

 

A 10W gas discharge element common in the medical industry is used in our Switch-Module for Tech-Lights.
The lamp has a colour temperature of approx. 5800K. Your can find more information and descriptions about these products in the relevant sections Mega D2, Tech-Leuchten Wrack maxi HID.

Halogen

Halogen bulbs produce the complete spectrum of colours. The red tones are particularly well produced although a large portion of the energy is converted into infra red (heat) radiation. For this reason, we utilise an aluminium reflector that reflects the heat out through the front of the lamp and thus prevents excessive heat build up and/or possible overheating inside the lamp.

Some manufacturers use so-called cold light reflectors made out of coated glass (common in household low voltage light applications). Unfortunately, this material allows the infra red radiation to pass back through the reflector to the rear of the lamp. The build up of heat creates a danger of overheating immediately behind the reflector and the life expectancy of components is shortened considerably.

In a cold light reflector, the invisible infra red portions of light are not exactly separated from the visible red light portions.
This bundling results in a large part of this visible red light, that is especially desirable under water, being absorbed.

The HLX-Halogen bulbs used in our lamps are filled with xenon gas and are particularly effective in producing light. The bulbs have a life expectancy of approx. 100 hours. The colour temperature is approx. 3400K.
Halogen bulbs are however commonly available on the household/DIY market. These bulbs usually have a comparatively low effectiveness in producing light but therefore have an extended life efficiency of approx. 2000 hours.
One of our 50W HLX-Halogen bulbs, powered with controlled over voltage has an equivalent light emmission to a 100W "DIY Bulb".

Conclusion

What are the advantages of an HID / LED-light?
An LED has an extremely long life span. It is considerably longer than that of a halogen bulb.
The LED is hard to break and very durable.
The cold white (bluish) light of an HID / LED is not as strongly absorbed by the water as the warm white (reddish) light of a halogen bulb. Therefore, underwater an HID / LED light has a greater range.
Due to the individual perception (only in dark environments!), cold white HID / LED light seems to be stronger than warm white halogen light .

What are the disadvantages of an HID / LED-light?
Fairly high costs of the HID / LED and the necessary electronics.
Bad rendition of the red colour.

Conclusion
We recommend the use of an HID / LED-illuminant for night dives in freshwater, for dives in murky and cloudy water and for cave dives.
Despite a rather low power consumption of the LED modules, a sufficient brightness and a considerable longer burn time is achieved.
(siehe Tomatentest)