NAO is the latest headlamp from Petzl - which brings together all the technological innovations of the past few years. Cree XP-G LED’s as a light source, 18650 Li-Ion cell as a power source, programming modes and charging via USB. Anything else? New Zephyr carrying system and "Reactive" - the system that automatically adjusts the light to your needs...


Some marketing data (maybe a bit more than some).

The rechargeable NAO headlamp adapts its two high power LEDs instantly and automatically to the lighting needs for greater comfort, fewer manual interventions and longer battery life. NAO is the first Petzl headlamp with REACTIVE LIGHTING technology: a sensor measures and analyzes the ambient light.


Nice, relatively light (instead of 187 catalog it weighs 190g, but it's a small difference) it appears to be a lamp refined in every detail. No edges except for switch - the switch itself is large and very easy to use. "Eye of Sauron" - as some call light sensor, for certain will attract the attention of every customer ;).

Petzl NAO out of the box.

The first thing that strikes my mind is a number of connectors on the power cord – we will see if in the future that will not be a problem.

The new strap system works flawlessly - the only thing that you have to do is to push the lock and tighten / loosen the tie on the back of the head. Headlamp keeps itself on the head very firmly, 4 anchor points on the battery holder greatly enhances its stability during the run.

What you can find inside ?

This time, Petzl does not save on cooling; almost half the space inside the head is filled by aluminum heatsink.

Petzl NAO - heatsink

The internal build itself is quite simple - of course if you are not trying to put everything apart ;). Head protector => heatsink => plastic box with driver and led’s => front cover.

Petzl NAO - main head parts.

In accordance with the trend in recent years - LED's are integrated on the driver board – modding this light won’t be easy.

The brain of this driver is STMicroelectronics STM8L151G2 Ultra-low-power 8-bit MCU with 4 Kbytes Flash, 16 MHz CPU, integrated EEPROM - yes dear user, you have a 16MHz processor on the forehead ;).

If you really want to spend some time on software development you can even make your own ROM. And maybe somebody will have to do so, because in the process of developing current firmware somebody killed the idea of strobe modes - no SOS or usual strobe in NAO. Maybe we should expect some firmware update in near future ? Or maybe, Petzl was the company that introduced the strobe mode in headlamps and now is going to end it?

Power supply

Before the first use, the battery needs to be charged, you must be patient cos it might take a few hours. Here is a bad news for potential users - yes inside the battery pack is 18650 Li-Ion cell, but it is connected with the wire and plug, which prevents the usage of 18650 cells easily available on the market.

Petzl NAO - battery pack.

Petzl NAO - battery

Don't panic, the plug is commonly available Molex 5264-3P with 5263 pins, for less than $1 you can make yourself a spare cell.

Petzl NAO - battery, pcm, ntc

The main problem will be putting inside of this „spare” a 100KOhm NTC thermistor - without that the electronics’ inside the battery pack does not recognize that you are using rechargeable battery and battery indicator does not work.

Petzl NAO - battery pack PCB

Greeting from Petzl’s engineers? :).

Petzl NAO - The early bird

„The early bird gets the worm” - but what does it do inside the headlamp I do not know. Maybe it's the motto over the entrance gate to some factory somewhere in Bulgaria? ;).

Hacking Petzl NAO =:]

So, the headlamp is powered from the single LI-ion cell, but what I have from that when I have a bunch of cells but I cannot use them ? And the 2xAAA alternative is to weak for any normal usage.

Petzl NAO - battery pack inside.

After quick check I noticed that there is no separate circuit for 2xAAA cells - everything is connected.

Petzl NAO - hacking the battery pack

Quick shopping in TME (Digikey for US citizens - or any well-stocked electronic shop) and within 48h I had all the components needed, Molex parts were used only for testing the circuit - finally there was not enough space for the plug. I bought a through-hole mount version of the NTC but you can use a SMD to save some space (it is this black blurred ball - in the final version it has been soldered directly to the board). Some cutting and soldering on the 18650 holder (don't use those from DX - total crap, with voltage drop over 0,5V) and after 1 hour I get the NAO as it should be since the beginning ;).

In the process of modding you have to remove the original socket and terminals for AAA batteries - so this modification is a rather one way ticket - though for the original battery you are getting only 6 months of warranty :P.

Petzl NAO - battery pack hacked

Alternatively, you can always buy a complete battery Petzl ACCU NAO. Although when the list price is $ 58 it is not an attractive option when branded 18650 3100mAh Li-Ion cell costs about $ 10 and the price for a rapid cell charger is also around $ 10.


Energy consumption.

Immediately after connecting the battery the head starts to draw about 4.09 mA of current, but it drops quickly to 0.21 mA, so you can safely leave the headlamp with battery inside for a few weeks.

Mode I-in V-in P-in calculated burn time
Reactive high 101,04 mA 4,05 V 0,41W 20,80 h
Reactive low 86,9 mA 4,06 V 0,35W 24,12 h
High 504,69 mA 3,79 V 1,91W 4,45 h
Low 371,06 mA 4,01 V 1,49W 5,72 h

Measurement of the Reactive mode has been made on the desk at moderate light - just to see how it works, because the headlamp adjusts very quickly to changes in light intensity and everyone will get different results.

As you can see Petzl is very cautious about burn times declarations - High mode is only 1:20 while in the battery there is enough energy burn for 4 hours. This is related with extending the burn time by the software - for example, declared burn time in reactive mode is 4h 40m (depending on usage). Because Petzl restricted itself to use only a single, non-replaceable battery, so they are forced to save a lots of energy in reserve "for later", because the final user won't be too happy when after 4 hours he will be left in the dark.

Something definitely is not ok with the „low” level in the continuous mode, it draws too much current and emits too much light as for declared 88 lumens - maybe I have some bug in my software ;).


The software package is not the smallest one - 68MB + some Adobe AIR updates. The interface itself is based on drag and drop technology so there should be no problems with that.

Petzl NAO - Petzl OS main screen

By default you are getting the Multi-Activities profile:

Petzl NAO - Multi activities profile

Here everybody will be able to choose his/hers favorite settings – In my opinion it will be better to show lumens instead of range, but it is, as it is.

When only the battery is connected, you are getting the information about the charging status.

Petzl NAO - battery charge status

How does it light ?

When you are covering the light sensor with your fingers to see how it works in the shop, it doesn't show you the efficiency of the system in practical conditions. But it Works !. In reactive mode the headlamp instantly changes the amount of light depending on where you turn your gaze. Just raise your head and look in the crown of the tree and the beam of light will follow ;). The usage of two LEDs with different collimator angles allows you to see what you have just under your feet as well as objects that are far away.

My NAO have a pretty nice tint of light, but the manufacturer does not claim to use selected LED’s, so as usual it may depend on the series.

Petzl Nao - HIGH - about 300 lumens.

Petzl NAO - high

Petzl Nao - LOW - it should be about 80 lumens, but in my opinion is 120-130 :].

Petzl NAO - low

Reactive modes, so as much light as the headlamp thinks that it should be enough ;).

Petzl Nao - reactive mode - HIGH.

Petzl Nao - reactive mode - High.

Petzl Nao - reactive mode - LOW.

Petzl Nao - reactive mode - LOW

Pictures made indoor and outdoor do not present the same amount of light, because the headlamp recognizes itself as much light you need. Practically, offered amount of the light in high mode (only one LED was working with a wide optics) was sufficient to illuminate the path to almost 20m ahead, which is enough to run, in low mode you can walk without any problems.

For reference, two headlamps that really have 200 lumens :

Black Diamod ICON 2012 - HIGH

Black Diamod ICON 2012 - HIGH

Princeton Tec Apex 200 – HIGH

Princeton Tec Apex 200 – HIGH


Ideal headlamp, almost – the power supply was unnecessarily complicated, they can follow the Sparks idea to use standard 18650 cells and combine it with reverse polarity protection to make it fool-proof. Then with 2 spare cells in your pocket user will have enough energy for whole weekend or even longer. But they choose the “Petzl’s way”, so now the user have to pay or make it by himself.

The Reactive Lightning system works fine, despite my initial concerns - although we will have to wait a bit to see how it will react in a dense fog, or when stuck in snow. In the manual there is a warning to do not use the headlamp in reactive mode during road biking – the lamp can switch off itself when encountering a car with headlamps on. So there are some risks ;).

Is it worth it ? In my opinion yes, but for sure it is quite expensive headlamp and not for every pocket. I still think that if they will cut reactive system, overcomplicated power supply, and make the NAO into almost normal headlamp powered from 1 or 2 18650 for $100, the competition would not have any chances. Definitely there is a room for RXP 3 on the market - but so far the Petzl NAO will be a class for itself ;)..


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