LED Lenser SEO5 Review

As the nights draw in, it’s time to dig out the trusty head torches so we can still make the most of the trails. Over the years I’ve gathered a rather healthy collection, but the most recent addition has become my turn to light. Through the Trail Running Team I was supplied with the new SEO 5 from LED Lenser, I’ve now used it on countless training runs, and races including the Lakeland 50, UTMB-TDS and the Dusk til’ Dawn, without complaint.

seo5-grey-img2When I’m picking a head torch for running, I’m looking for something that is light, bright and reliable, it most also be comfortable to wear, as it’s going to spend up 10 hours on the head during longer races. It must also be simple to use, and if battery changing is required, that needs to be straight forward.

The SEO5 is a compact single unit head torch, in that the light also houses the batteries, so that the whole unit sits on the front of the head. Despite this it still feels well balanced and is compact enough to go largely unnoticed. Weighing in at a little under 105 grams the SEO5 still manages to kick out 180 lumens on full power and dim’s down to 20 lumens to extend battery life from 7 hours up to 25 hours.

The light beam is focusable by simply twisting the front housing, allowing you to zoom the light from a wide arch to a narrow spot which reaches a claimed 120 metres. It can also be tilted down to aim it closer to your feet for technical sections or map reading. I’ve found the ratchet system very secure, with no slipping unlike some “droopy” alternatives.

In use, I’ve found the SEO5 to be an almost perfect light. The high beam, is very good, with a nice clear white light which picks out details in technical terrain with ease. Low beam is sufficient for running on fire roads, and good paths or simple map reading. A quick press of the button scrolls between high beam, low beam and strobe, making for a no fuse approach to selecting your light output. A long press will switch between the red and light LED. Whilst the power button is relatively small I have had no issues switching light output when wearing gloves. I still find this light comfortable and easy to wear after 10 hours of running. The twisting focus is excellent, I tend to run with it set to flood mood most of the time, but being able to quickly twist it to spot for navigating or more technical ground is very handy.


Battery change is a breeze, once you’ve done it once or twice. I had to do it mid race during the night section of the TDS and once during the Dusk ’til Dawn. It can be done in the dark, but like everything is easier if you have a back up light to assist. I don’t consider this a problem as all races require you to carry a back up light anyway. I tape my batteries together, so it’s a simple matter of flicking the old ones out and pushing the new ones in. This makes battery changing with cold fingers less of a problem, means polarity is already sorted and you don’t lose loose batteries in the bottom of your pack.

So what’s not to like..? The battery life is on the short side, 7 hours at max output means in longer races that go into or through the night you will need a battery change. Comparing it to my Petzl Myo which kicks out only 140 lumina but lasts 53 hours, it’s a substantial difference. However the Myo weighs almost twice as much, is more expensive and uses heavier AA’s. Besides a spare set of batteries only weigh 35g. My white headband is starting to look a little grubby, but this is removable and washable, I’m just to lazy to do it. There is no safety switch, so the potential for the light to be knocked on in your bag when routing for other kit, the SEO5 is not alone in this and most head torches suffer in this regard.

LED Lenser SEO5 Features:

  • Weight 105g
  • Output 180 lumens
  • Flashing mode
  • Adjustable beam
  • 3 AAA batteries
  • Red light
  • Battery life 7-25 hours
  • Adjustable angle
  • IPX4 Waterproof
  • Washable headband
  • Carabiner
  • Price RRP £49.99


on “LED Lenser SEO5 Review
15 Comments on “LED Lenser SEO5 Review
  1. I have one of these lights. I am sure that I did not receive any operating instructions with it. While I am fishing at night with it a red flashing light comes on periodically which is most annoying when you are trying to tie a hook on or put bait on. what is this flashing red light for and can it be turned off ?

    • Hello Ian, Sorry for taking a while to respond… It sounds like the low battery warning. I would try a fresh set of batteries and see if it goes away.

      • Thanks for your help Reuben…..and yes you are correct, a new set of batteries has done the trick. My wife suggested this at the beginning , ( as she continually reminds me ! ) but because the light was still reasonably strong I discounted that theory . Also , I figured the flashing red light must have another purpose , in line with the feature of the flashing white light that can be set. The original batteries didn’t last very long at all , probably because they had been sitting in the shop for sometime before being purchased.

  2. “There is no safety switch, so the potential for the light to be knocked on in your bag when routing for other kit, the SEO5 is not alone in this and most head torches suffer in this regard.”

    This is incorrect, the SEO5 does have a safety switch, when you turn your light on, if you hold for 2 seconds it turns to red light but if you continue to hold for another 3 seconds, you have put it into safety mode.

    If you try and switch it on, just a few red blinks will appear as you will need to hold down the button for 5 full seconds before the safety switches off and the light comes on.

  3. Hi Ian, just in case you hadn’t figured it out yet (I know this is an old post), press and hold the light switch to activate the travel lock. Light will come on immediately, keep holding, after 5 seconds or so will switch to red light mode, keep holding, after another pause red light flickers and goes out. Now when you try to switch on the unit it just flickers the red lights a few times and remains off. This avoids the problem of the headlamp accidentally turning on in a pack. To activate properly now you’ll need to press and hold the on/off switch for some time. This will return it to normal operating mode.

  4. Problems with SEO5 LED Anyone had issues with LED not staying on? Fresh batteries but led will not stay on.
    Sensor issues?? (Can’t find company contact info) Have to say this is the best LED headlamp I have owned and
    really really miss it!! If anyone has repair info please forward.

    • Yes, I am having the exact same problem. I turn on the lamp and after a few seconds it switches off. It is only a few months old and it’s really annoying. Worked perfectly for a while, until I began to play around with the different settings. If you’ve found a workaround I’d love to hear about it!

  5. no, this is a different issue, and I have exactly the same problem. I turn the headlamp on normally, it works for 15 – 20 sec, then it switches off. Annoying and (if using as bike headlamp) dangerous! Anyone figure this out??

  6. Yip same problem…a few seconds and it turns off. Very annoying when you are riding a bike at night! Anyone out there can help on this issue

    • There appear to be some faulty units floating around. I contacted the company about the issue and they promptly replied that it appeared to be a defective product. Told me to contact the distributor in my country, who replaced the SEO5 without any fuss whatsoever. The new one has been working like a charm since.

      • It doesn’t matter how good a product is overall, there is always a risk of a small number of defective products. It’s how a company handles the faulty stock that is important, so I’m pleased to see here that LED Lenser looked after you. I have several Led Lenser products and I’m very pleased with them all.

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