Flickering/PWM in new Fenix HL55

Well folks after the nitecore HC90 switch issue i decided to give another chinese brand light a try

Turns out that a fresh out if the box Fenix HL55 has a quite noticeable flicker on low, you can see it in the video below

This is with Fenix 3400 mAH bats, and Nitecore 3400 mAh bats, all new, same issue

And yes i did clean the contacts and threads

Does anyonr elses HL55 have this issue?

Im fairly new to these Chinese made Fenix and Nitecore lamps ... I uually own petzls which dont have these problems

Are these issues somethig folks here just expect and tolerate with these brands ?????

This is two brand new out of the box headlamps from these chinese manufacturers with issues!!

I have not spent much time in eco mode but I checked it out after seeing you mention this. Yes, my unit has a slight flicker to it in this ultra low mode. The other modes... low, med, high and turbo are all rock solid. For my use I spend most of my time in low and high so it's not much of an issue for me.

Thanks for the update

its actually eco mode this happens in, im not used to the fenix terminology yet!

Interesting... I noticed the same exact thing happen to my new Fenix TK09. It'll flicker just like that in the low/eco mode, and in medium and high mode that flicker goes away, just as you and Crotulus are experiencing. I've also noticed that the PWM is especially noisy (loud ringing), more so than any of my other fenix lights by far.

I tried cleaning the contacts with rubbing alcohol, but to no avail, I still get that flickering in the low mode. I'm not sure wether or not it's an "issue", or perhaps I am just more sensitive to PWM. Regardless, this is one of the reasons why I prefer CC over PWM.

I contacted the fenix distributer and the said fenix wasnt aware of the issue and that this shouldnt be happening with the light

Ill post up with my experience of Fenix CS and the resolution once it gets resolved ... And if the new light they send me has any similar issues

For reading at night it definately and issue .... Its like trying to read with a slowly strobing/flickering light

thanks folks

Yes it's certainly an annoying effect. I emailed Fenix a few days ago about the occasional flickering, and they insisted I send the light in for warranty service. I decided to pass on that, as I don't really use my TK09 much anyways. I am sure they'll want you to send your HL55 in as well. I can see how it'd make reading difficult.

I really had high hopes in this headlamp but started getting a bad feeling when I saw that 900 lumens burst mode: another victim to high-lumen advertising!
I was disappointed to see that the lowest mode was 10 lumen and there was no red LED... now the flickering problem. Too bad because it's pretty light and it has an IPX8 rating!

I recently received my HL55vn and hadn't noticed this. But admittedly my use on low has been minimal and when walking, so any minor flickering wouldn't have been noticable. Anyhow, I just tested the light on low standing about 3' from a wall and it does flicker a little. So I decided to test it with some reading in the dark. While the flickering is noticable if you are looking for it, it really isn't noticable if you aren't looking for it - i.e absorbed in your book. 20 minutes of reading didn't bother me at all. This is now my primary backpacking light and I don't know why anyone thinks this minor flickering (only on low) would be a deal breaker. Is the light perfect? No. And while I have beaucoup lights in my collection, including many customs, I don't think any of them are perfect. This light has 5 (if you count Boost mode) well spaced modes, is lighter than my other 18650 based headlamp and disipates heat extremly well, which is very important on my vn modified model on high and boost. I also like the fact I'm able to use this light without the top headstrap and it doesn't move around. I'm keeping mine and wouldn't hesitate to recommend it to others. If there was only one change I could make it would be to increase boost mode timing to either 1 or 2 minutes. But even 30 seconds is lots of time to look around before the light returns to whatever mode it was in when you entered boost.

I'm not certain this "flicker" is a manifestation of PWM. It doesn't seem regular enough for that. But it may be some other artifact of regulation or the driver used. It'll be interesting to see what fenix has to say. I'm sorry this is so irritating to some folks. It seems incredibly minor to me. As I said, I didn't even notice it until I read this thread. And unless I concentrate on looking for it, I don't notice it now. Did I say I really like this light?

I noticed the issue right away

thr fenix dsitributer indicated that fenix isnt aware of the issue, also its possible that all of the fenix HL55 have this issue as they tested a new one in stock and it flickers on eco

Whether you consider it an issue is up to you, there are some folks who are much more sensitive to PWM/flickering than others here

What astounds me is that this is happening on fenix lights which are generally considered quality lamps here

it doesnt happen on any of my petzls, even the budget priced ones

it seems that some folks here "cheerlead" some light without mentioning their drawbacks or quirks

these issues should be documented and then the purchaser can make the decision as to whether or not its acceptable .... Rather than having the issue hidden or being put down for pointing it out

I have a VN version comeing I'll let you know what its like.

Hmm at least if PWM then it would not be an issue but that fenix say it is not meant to do it is a worry, just hope it won't lead to further issues with anyone's lights and maby there will be a simple fix, I doubt I'll use eco node much though so dksent bother me.

I'll take a bit of flickering over switch issues!

Does anyone know if the HL55 ever steps down from High to a lower output?

I suspect it does but it doesn't the runtime on High would be excellent. Definitely worth considering for that alone despite the 10-lumen low - at least after Fenix fix the flickering issues!

High is not really that high, so no step down I think as he at sinking is excellent, only step down on turbo.

I guess I won't know till it gets here but I see no mention of a second step down, but it doesn't need one...

Thanks a lot. Even if heat-sinking is good, 420 lumens for 3 hours 45 minutes would be a very good runtime even on a 3400 mAh 18650 cell. I am not saying it's impossible but I think is unlikely! I could be wrong of course.

Yes you could be right!

But also bear in mind that's FL1? So it will only be doing 10% output at that time, so when you factor in the dropped output it can proberly do it, and again heat will be less so I doubt there is a second stepdown, but I am possibly wrong, won't know till mine gets here.

Guess we will find out soon enough though.

Labrador72 said:

Does anyone know if the HL55 ever steps down from High to a lower output?

I suspect it does but it doesn't the runtime on High would be excellent. Definitely worth considering for that alone despite the 10-lumen low - at least after Fenix fix the flickering issues!

Click to expand...

It only steps down once the cell is depleted to the point it can no longer keep the High output going. The only timed step down is the 30s Burst output.

The runtime graph in my forthcoming review will show this.

I'm still waiting on feedback from Fenix regarding the flickering issue, and have stopped work on the review until they update me.


CyclingSalmon14 is correct in that the full runtime on High does include stepped down output which is due to the cell no longer being able to maintain the previous output level.

subwoofer said:

It only steps down once the cell is depleted to the point it can no longer keep the High output going. The only timed step down is the 30s Burst output.

The runtime graph in my forthcoming review will show this.

I'm still waiting on feedback from Fenix regarding the flickering issue, and have stopped work on the review until they update me.


CyclingSalmon14 is correct in that the full runtime on High does include stepped down output which is due to the cell no longer being able to maintain the previous output level.

Click to expand...

is it possible to get a preview of the runtime graph on high, or if you could let us know how long it stays ~400 lumens before stepping down?

also does anyone here have a HL55 that does NOT flicker on eco?

im debating whether to keep this headlamp, and would really like to know if its a design or QC problem ... basically are there ones out there that dont have this issue

My order from vinh just shipped today expect to have it in 4-8days but up to 14 depends on shipping method. No tracking unfortantly, I'll let you know if I have flicker, either way it dosent bother me much though, but like you I want comment from fenix and closure on the issue, Ie should we be concerned for any problems that may develop due to this.

bearbreeder said:

also does anyone here have a HL55 that does NOT flicker on eco?

Click to expand...

That's a good question. I saw even in the German flashlight forum they reported a slight flickering on the Eco mode. It may be a QC issue but it seems to be across several batches.
http://www.taschenlampen-forum.de/fenix/36050-review-fenix-hl-55-kopflampe-900-lumen.html/

Judging by a naked eye and camera I would say that the light output it is rather unstable in eco mode than it is flicker effect.

Fenix HL55


Armytek Wizard Pro - Firefly 1, 0.4 lm


You can compare with Rayfall H1L

subwoofer said:

It only steps down once the cell is depleted to the point it can no longer keep the High output going. The only timed step down is the 30s Burst output.

The runtime graph in my forthcoming review will show this.

I'm still waiting on feedback from Fenix regarding the flickering issue, and have stopped work on the review until they update me.


CyclingSalmon14 is correct in that the full runtime on High does include stepped down output which is due to the cell no longer being able to maintain the previous output level.

Click to expand...

Thank you for the info Subwoofer, looking forward to your review as always.
For the time being I pulled the trigger on a HC50 (your review is also to be blamed in part :thumbsup but may get the HL55 too at some point if overall feedback is good.