The Petzl Iko Core Headlamp is a headlamp with an external battery pack, a weight of only 79,9 grams and it produces 500 Lumens according to Petzl. Enjoy the review!
- Weight: 79,9 grams
- Size: 51,5 – 63,6 cm
- Price: € 79,95/ $ 89,95/ £76,49
Petzl is one of those brands that always seems to deliver and in this case with the Petzl Iko Core Headlamp – spoiler alert! – this is not different. Although I do have a few remarks that you should take into consideration if you are planning to buy a new headlamp and have the Petzl Iko Core Headlamp on your hot list. Now let’s get into detail.

Size and weight
The Petzl Iko Core Headlamp weighs on my precise and calibrated scale 79,9 grams. This is the weight for the headlamp with the Core rechargeable battery in it. Petzl claims a weight of 79 grams and the small difference of 0.9 grams is neglectable. The Core battery has a weight of 22,8 grams and the pouch that comes with the Iko Core weighs 4,9 grams. If you think the rechargeable Core battery is heavy, think again. The Petzl also operates on 3 AAA batteries but they have a combined weight of 34,5 grams.
Battery
The Petzl Core rechargeable battery has a capacity of 1250 mAh. To charge it I need a USB-cable and that comes in the package. The charging itself is done directly on to the battery and not with a connection to the headlamp. This is very practical because now I can recharge the battery while using the Petzl Iko Core Headlamp with a second Core battery or with 3 AAA batteries. The battery housing is partly made of plastic and has a rubber cover. Taking this cover off to get access to the battery is with cold hands or gloved up a bit of a fiddly proces.

Headband
The headband of the Petzl Iko Core is a very special one. Petzl named it the AirFit headband and it is not made out of the usual elastic band material but made of rubber and plastic. An elastic drawcord with a toggle is used to adjust the headband to the head. The small lamp unit sits in front of the headband whilst the battery sits on the back, a little bit above the Atlas in my neck.
Due to the special shape of the AirFit system, the headband sits perfect on my head and comfort is super too. It’s very stable not only for outdoor use but also when running. I did a couple of trail runs with the Iko Core and every time I was surprised about the fit and how well it stayed in one place. Three remarks on the headband though:

1) it is usable with a beanie but not in combination with a cap;
2) the adjustable range ranges from 51,5 cm to 63,6 cm which is a bit limited for smaller head circumferences or large head circumferences;
3) it does not fit with the climbing helmets I own.
Headlamp
The headlamp is a pretty clever one too. It is a very small unit that has a pivoting point on the headband. Because of this it is very easy to tilt it up- or downwards. The pivot gives enough resistance to prevent the lamp unit from changing position when being active. 7 LEDs house in two rows in the lamp unit: a row of three and beneath that one a row of 4.

Button
To switch the headlamp on and off and to change the light modes, the Petzl has a button that – unlike a lot of other headlamps that I own – is situated on the bottom of the lamp unit. The button is orange and made from a rough rubber material that provides good grip to the thumb even when wet. The button is hidden between two little hills so that when I reposition the unit, I don’t accidentally press the button. With bare hands the button is very usable but gloved up it is quite a small button and not very practical. The Hestra Ergo Grip Active Gloves I reviewed earlier work fine tough. Thick winter gloves? Unusable!

Lighting modes
The Petzl Iko Core Headlamp has three lighting modes: Maximum burntime, Standard and Maximum Power. Petzl claims that in the Maximum burntime position (the top row) the Iko Core produces 6 lumens, has a range of 10 meters and a burntime of 100 hours. For the Standard burntime (all LEDs) they claim 100 lumen, 45 meters and 9 hours burntime with 2 h 30 min reserve. In the Maximum Power (all LEDS) position the Iko Core has a power output of 500 lumen, a beam that goes up to 100 meters and burntime of 2 h 30 min and a 4 h 30 min reserve. In Standard and Maximum Power the Petzl automatically switches to the reserve mode to save the battery and extend battery time. This has proven to be very handy!

What the Petzl does not have is a red LED for reading maps when navigating at night or reading a book in my tent. This is a bit stupid. Something that I could not get accustomed to is the fact that when in a lightmode pressing the button results in turning the headlamp off and not going into the next light mode. Getting from Standard tot Maximum Power means pressing the button four times.
The white light of the Petzl Iko Core is not ideal for reading a map. The Petzl Iko Core should have a red LED for reading!
One more important thing: The reserve mode is NOT switching back to the Maximum burntime mode but to a mode that I can just see around me and still continue the hike. In numbers: 0.25 Lux at 4 meters. Yes Lux! Now let’s talk about lumens and Lux.
Lumens versus…
So, in Maximum Power Petzl claims 500 lumen. About Lumens there is a lot to tell. Lumens is a method of measuring how much light is emitted by the light source. The good thing about Petzl is that they are absolutely clear on how they measured it: they test conform the ANSI-FL1 Standard. This standard dates back to 2009 and the amount of lumen a light produces is tested in a sphere.
Because Petzl tests with this standard I – as a consumer – can compare the Iko Core to other headlamps that have been tested with the same standard. But…. The ANSI-FL1 Standard does not say that much about real outdoor life. Lumen is just a way of expressing how much light – the light intensity – the lamp produces. And that is the whole point with Lumens, it is not that important. Important is the usability in real life. Now let’s talk about Lux.
…Lux
Lux is – like Lumen – a way of expressing an amount of light but with Lux we talk about the amount of light that reaches a certain spot. So this is actually the useful amount of light for your eyes and the visibility. In the past I did quite a lot of testing on headlamps for the magazine I used to work for. We tested headlamps by measuring the Lumens and the amount of Lux that reaches a certain spot in the R&D laboratory of Philips car lighting. In this laboratory we not only measured the amount of Lumen and Lux but also the lighting pattern. After we did this several times, we made our own lab in the basement of the office. You might understand that since I left the magazine I don’t have this possibility anymore so now I do almost the same, but outdoors.
Field lab
For every lamp that I review I measure the amount of light in the different lighting modes that reaches a black square at 5 meters, 10 meters and 20 meters. Five meters is the point that I believe is a good distance while running or just looking around your camp. The other two are more important when speeds get higher or when you need the lamp also for exploring the area around you. With a simple Lux-meter I figured out that the 500 Lumens is measured at almost 1 meter distance. Although this is not 100% correct scientifically, I better say that at 1 meter I measured 500 Lux. For the Petzl Iko Core Headlamp in the different lighting modes I measured in a very dark forest the following values:
- Maximum burntime: Max: 5 Lux at 5 meter, 0 Lux at 10 meter and 0 Lux at 20 meter.
- Standard burntime: 10.4 Lux at 5 meter, 2.1 Lux at 10 meter and 0.04 Lux at 20 meter.
- Maximum Power: 30.9 Lux at 5 meter, 7.1 Lux at 10 meter and 1.8 Lux at 20 meter.

For so far the numbers, what does this mean on the trail or around the campsite?
Beam patterns in real life
I have tested the Petzl Iko Core Headlamp sind late june and of course in that periode the sun went down pretty late so the headlamp was mainly used at night when nature called. The last couple of months I used is when running, hiking and around my campsite. I have used it with clear nights full of stars and in the pouring rain. One thing that I love is the beam pattern in Standard and Maximum Power.
The beam pattern of the Petzl Iko Core gives good visibility in front of me… …but also enlightens low hanging branches.
The reason for this is the fact that the 3 LEDs in the top row provide a nice circular beam that goes from the trail in front of me to quite high above my head so I can see the trail and low hanging branches. The 4 LEDs on the second row provide a smaller round beam in the distance so I can see further away what is ahead of me.
I used the Standard position the most: nice balance of light and battery life. I only needed the Maximum Power for trickier parts of the trail and when trail running. The Maximum Burntime position… I think it is good enough around camp and walking on trails. The 0.25 Lux of the Reserve mode is comparable to hiking with moon and no clouds. We all know that when our eyes are adapted to the dark, a full moon is fine for good visibility.

The Petzl Iko Core beam in Standard burntime mode. The Petzl Iko Core beam in Maximum Power mode.
Pouch = Bonus
What can I write about the pouch of a headlamp? Well, quite a lot. I already mentioned the weight that is less than 5 grams but the neat extra bonus of the pouch is that it doubles as a diffuser. Put it over the Iko Core Headlamp and I have a nice lamp to put in my Helinox Table One or hang in the top of the tent, like the Hilleberg Anaris I reviewed earlier. And it works as a softbox lamp for photography too. So… Pouch = Bonus

Battery life in practice
I already mentioned the battery life that Petzl claims for the Iko Core headlamp. And to be honest: I don’t have much to add. I checked the numbers on the Maximum Power several times and Petzl’s numbers are almost spot on. With a measured average of 2 h 22 min burning time in full blast and then the unit switched to the reserve mode, the Iko kept on burning for an average of 4 h and 36 min. I like this. I like this a lot! What I don’t like is the charging time: it took me with the computer on average 3 h 35 min.
One small suggestion from my side. When you buy the Petzl Iko Core Headlamp, buy an extra spare Core battery with it. The reason is not that I think everybody should buy rechargeable batteries but it is the small print in the Petzl manual and also on the packaging. With 3 AAA batteries the Petzl does NOT produce 500 lumens but only 350 lumens.
Waterproof
Like most headlamps that are not used for diving or caving, the Petzl Iko Core Headlamp is rated at IPX4. IPX4 means it is only protected from splashing water from any direction. So it is not waterproof. I have been using the Petzl Iko Core Headlamp in the pouring rain a lot and I guarantee that rain does not affect the Petzl. If you need a 100% waterproof headlamp, buy an IPX8 rated one.
Verdict
The Petzl Iko Core Headlamp is a headlamp that I like in more than one way. The most important is the beampattern and the amount of usable light in Standard en Maximum Power mode. Also, the round beampattern is perfect for hiking and trail running. The energie Reserve mode provides enough ‘moon’ light to continue hiking. I do miss a red LED for reading maps when navigating at night. The weight of 79,9 grams is fine, the pouch that doubles as a diffuser is a nice bonus and the comfort of the very special AirFit headband is super. Be aware that the adjustability of the headband from 51,5 cm to 63,6 cm is a bit limited.
The on/off button could be a bit bigger so it becomes more practical when wearing winter gloves. I also would like to get into the next light mode when I press the button and not switch the Ico Core of. The Petzl Iko Core Headlamp has proven to be IPX4 water resistant and sturdy; after 4 months it still looks new, almost. The price of € 79,95/$ 89,95/ £76,49 is not cheap but money well spent if you buy one. I rate the Petzl Iko Core Headlamp at 8,1 out of 10 points.
Information: www.petzl.com