Light-Test.info

Cree XP-G2

When Petzl introduced NAO they have used the Cree XP-G leds - the best available choice in leds category. LED manufacturers do not pay too much attention to the lighting producers. At the beginning of the year Cree announced reaching 160lm/w and as always, half year later Cree XP-G2 appear on the market. When will they appear in Petzl headlamps? Who knows... When will they appear in my headlamp? As soon as I get the package :).

So, lets talk about a new LED’s and modding of the Petzl NAO.

 

Some theory.

In short, the difference between XP-G and XP-G2 effectiveness is described as 20% more lumens from watt. Does it mean that we will get 20% more light compared to the XP-G2? No.

The first component of better effectiveness is lower forward voltage :

Cree XP-G2 forward voltage

Which means that LED is more effective and the batteries will lasts longer - it will not provide any more light.

The second component is change in led junction temperature for which led has been sorted into bins. Earlier measurement was made for 25°C, now it is 85°C.

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Cree XP-G2 junction temperature

This means that we are getting just 10-13% more light in real use.

The third component has nothing to the with effectiveness. The light distribution angle has been changed from 125° to 115°, which in practice means that using the same optics we will provide better focusing resulting better range.

Modding.

Cree XP-G2 has the same footprint as XP-G so changing it is not mechanically problematic. More problematic is PB-free surface mount soldering and fitting leds on the same plate as driver. This increases the risk of damaging the driver during modding. Novice modder may end up with the components just “sailing away” from the plate.

Petzl NAO driver with the Cree XP-G leds

Petzl NAO - driver, cree xp-g

Petzl NAO driver with XP-G2 leds

Petzl NAO - driver, cree xp-g2

What to expect ?

Gain out of the led change from XP-G to XP-G2 will not be spectacular, 10-12% is hardly visible. From moder’s perspective the most visible will be the change of tint (the producers often use cold leds). We can choose a color we like. In addition, in case of Petzl NAO supposing light increase by 10% and lowering energy use by 10% in Reactive mode, there is a chance of a significant extension of burn time. It is caused by headlight having defined light level, what causes Reactive mode not to increase the amount of light visible to user.

Petzl NAO, manual mode HIGH

Petzl NAO - XP-G2 mod - manual high mode

Petzl NAO, manual mode LOW

Petzl NAO - XP-G2 mod - manual low mode

The increased amount of light and better focusing are visible, but also the change in color. To mod or not to mod? Why not if you want to - Don’t expect spectacular results like while modding i.e. Myo RXP, but if you could also replace battery to Panasonic 3400mAh - then theoretically there is a possibility of extending working time from 5-6 to 9-10 hours on one cell :). This means that it will last the whole night during summer events.

Petzl NAO - Panasonic NCR18650B mod

Anticipating the question - How to distinguish Cree XP-G of the XP-G2?

Cree XP-G2Cree XP-G

On the left Cree XP-G2 on the right Cree XP-G - version 2 has a silver background and on the chip you do not see the characteristic 4 strips, only small dots (only at high magnification ;).