# Chinese Led headlamp High EM radiation ?



## Doh13 (May 2, 2015)

Forgive me if this has been discussed before ,my internet connection is too slow at the moment to search. 

I bought a Chinese led headlamp that takes 18650 batteries it also makes a high pitched noise on medium brightness I noticed after wearing it for awhile (with a hat on) that my forehead felt a bit painful where the lamp was sitting, almost like my forehead was "burnt" but there is no red marks, that feeling lasted about 3 weeks or more so it wasn't from being too tight etc. . 
I was thinking maybe the Led lamp got hot and burnt my head but I put the led headlamp on again at a later date making sure that it would not touch my skin or get hot and now I have the same burning sensation on my forehead and I know for sure that it never got too hot to burn me. I knew something wasn't quite right so i did some research and found that some cheap led headlamps may have crappy power supplies that put out a lot of EM radiation (especially on the medium brightness setting) I think that the EM radiation from this led lamp May have caused this to happen to my forehead!

I found this video as well.. https://www.youtube.com/watch?v=15d-3enuc2k
My question is did I get a dose of electromagnetic radiation to cause my forehead to burn or am i just being paranoid thoughts?


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## Rat (May 2, 2015)

Hi
What brand is it or is it a cheap Chinese one like in the video ?
I have just tested my Spark modified headlamp and it only put out 0.5 milligauss but did spike to 5.0mG when turning off.
I will test my Nitecore tomorrow.


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## RetroTechie (May 2, 2015)

Welcome to CPF, Doh13! 

Before you go chasing EM radiation ghosts, :tinfoil: I'd suspect a *chemical* issue first. The Chinese are known for not caring too much about consumer safety, and therefore it's not uncommon that nasty chemicals are used/found in products. Especially cheaply produced stuff.

I once bought a toiletry bag. Nothing special, a few sheets of black canvas, pockets & zippers. A short while after I got home, I noticed a nasty smell in the room. Went on a search, and what'ya know? Smell came of that newly bought bag (especially after I took off the plastic wrapper!). It kept spreading that smell for like 6-7 weeks after. I suspect some nasty volatile chemical was used in the production of that bag's material, nicely kept with the bag by its plastic packaging.

Now imagine something similar with your headlight, with the light's body & headband nicely between your forehead, and a device to heat things up. 

As a quick test, I'd try the following:



Remove flashlight & battery holder (if separate) from its headband. 
Isolate the side of both headlamp & battery holder that faces your head, using a sheet of material that definitely doesn't allow volatile chemicals to pass _through_ it. Aluminium foil comes to mind... 
Attach both to a headband that you've used before, had for years, and/or rig something up using plain cotton, sweatbands, a few handkerchiefs or such. 
Use this contraption for a while at such a power level, that you're _sure_ the heat on your forehead isn't an issue. 

Probably one of 2 things will happen:

a) Same issue as before. In this case maybe your head is more sensitive to heat than you thought. Or that EM radiation issue might be worth investigating further.
b) Issue disappears. In which case you could rule out heat, EM radiation, and continue tests to determine whether battery holder, flashlight casing/finish, or the headband itself/connecting materials are to blame.

What material is the flashlight body? And please tell us what exact product we're talking about.


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## PhotonWrangler (May 2, 2015)

I agree with RetroTechie. Is there any nickel in the case? You might be allergic to nickel and not know it.


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## SemiMan (May 2, 2015)

Your internet connection is too slow to search ... huh? ... but you could post in just the right section?

Paranoid ... is what I am leaning towards.

To the people saying chemical, not the op said he tried again without it touching his skin.

I am leaning towards psychosomatic.

While there may be EMI, the energy and frequency range on a headlight will be quite limited.


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## PhotonWrangler (May 2, 2015)

I've been in the presence of some pretty high EMI fields many times and felt absolutely nothing.


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## Doh13 (May 2, 2015)

The headlamp is the same as this :

http://www.ebay.ca/itm/12W-CREE-XML...423?pt=LH_DefaultDomain_0&hash=item566d717887

I did not have it touching my actual head when it made my forehead feel "burnt" both times and i do not believe it was too tight.. even if it were too tight i shouldn't have this feeling on my forehead for over 3 weeks and then have it happen again the next time i use it. 
When i used the headlamp last night i had it on medium for about 10 minutes when I got annoyed by the humming/wining noise it was making i put it back to bright which doesn't wine. The part of the lamp that would touch my bare head would have been plastic the actual lamp is suspended and held on by 2 screws but im pretty sure it wasn't to do with being too hot or allergy to the material because i had a toque on and the lamp was over top of the toque so it never even touched my head. I am hoping i am just being paranoid. i could do more testing by putting it on my arm or leg for about 15 minutes and see if the same sensation stays with me but im not sure if i want to do that .


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## Doh13 (May 2, 2015)

SemiMan said:


> Your internet connection is too slow to search ... huh? ... but you could post in just the right section?
> 
> well my home internet is a 1.5 Mbps connection and its usually 0.35 Mbps which is equal to dialup and gets rather annoying after a fashion, I can search things but i was all searched out at the time i posted this it wasnt an excuse.. i just did not want to waste half the day seeing if this subject has been talked about on the forum lol.


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## Doh13 (May 2, 2015)

SemiMan said:


> I am leaning towards psychosomatic.
> 
> While there may be EMI, the energy and frequency range on a headlight will be quite limited.



All I know is that after using the headlamp in question my forehead feels like its been mildly "burnt" without actually having red marks or tell tale signs of burns which causes mild pain in my forehead for a very long time after use. I would compare the pain to a sunburn.. I did not even realise these lamps put out Em radiation before last night when i was searching google as to why this might be happening to me.


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## RetroTechie (May 2, 2015)

12W? Seems like a lot of power for a headlamp... Btw you can be sure that "up to 2800lm" claim is BS, more like ~900-1000lm (?) if that 12W is accurate, driver is efficient, LED is well cooled, and a genuine Cree XM-L from T6 bin as specified (note that's a lot of if's).

Perhaps it's a heat issue after all? You don't _necessarily_ need a high temperature for your skin to suffer burn-like effects, if the exposure is continuous & prolonged. That the lamp is free-hanging helps, but the plastic holder may still get hot, and still transfer enough heat to your forehead. Especially considering the thin layer of skin you have there. :sweat:

What batteries (brand, mAh) do you have in there, and how long do they run @ full power?


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## Doh13 (May 2, 2015)

RetroTechie said:


> 12W? Seems like a lot of power for a headlamp... Btw you can be sure that "up to 2800lm" claim is BS, more like ~900-1000lm (?) if that 12W is accurate, driver is efficient, LED is well cooled, and a genuine Cree XM-L from T6 bin as specified (note that's a lot of if's).
> 
> Perhaps it's a heat issue after all? You don't _necessarily_ need a high temperature for your skin to suffer burn-like effects, if the exposure is continuous & prolonged. That the lamp is free-hanging helps, but the plastic holder may still get hot, and still transfer enough heat to your forehead. Especially considering the thin layer of skin you have there. :sweat:
> 
> What batteries (brand, mAh) do you have in there, and how long do they run @ full power?



I agree most of the specs are likely BS and I realized that may be the case when I purchased it but I do know that it is very bright and i can see very good with it on compared to a normal flashlight . I have never compared it to other high quality led headlamps though. The plastic part that would be touching my bare head does not seem to get hot and if i remember correctly each time it "burnt" my forehead i was using the lamp on medium brightness and also had a hat on so the lamp was not touching my bare skin. I am using some green samsung 18650 Batteries that came from a Laptop battery i dissembled. I am only using one battery in the lamp which holds 2 because i don't think that they have protection built into the battery so charging 2 batts with the built in charger might get risky.


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## SemiMan (May 3, 2015)

Doh13 said:


> SemiMan said:
> 
> 
> > Your internet connection is too slow to search ... huh? ... but you could post in just the right section?
> ...


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## D6859 (May 3, 2015)

Maybe it's that the pressure (and little addition to heat) on your forehead that made your skin sweat. Swet combined with the chemicals might cause your forehead feel burnt. What was the shape of the "burnt" area like? 

Btw, my headlamps all send out EM radiations. Mainly light and heat radiation (infrared light)


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## Doh13 (May 3, 2015)

SemiMan said:


> Doh13 said:
> 
> 
> > But you are able to search and view YouTube videos ....
> ...


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## Doh13 (May 3, 2015)

D6859 said:


> Maybe it's that the pressure (and little addition to heat) on your forehead that made your skin sweat. Swet combined with the chemicals might cause your forehead feel burnt. What was the shape of the "burnt" area like?
> 
> Btw, my headlamps all send out EM radiations. Mainly light and heat radiation (infrared light)



There is no red marks or actual burn marks on my forehead and as i stated before it wasnt touching my skin i had a hat on each time this has happened. It just feels like a bad sunburn I still feel it now actually and I haven't had the headlamp on since the evening before my OP.


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## Doh13 (May 3, 2015)

i was thinking maybe it could have been too tight on my head but i never had the lamp that tight on my head.. plus even if there was pain from it being too tight it shouldn't last for weeks. also wearing a hat while having the lamp on should rule out allergies. All i know is something is odd about this headlamp and when i use it my head has a weird lingering burning sensation I dont think it will be going on my head again. Maybe ill give it to a friend without telling them what happened to me and then see if they complain of the same issue =) .


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## PhotonWrangler (May 3, 2015)

Could you be allergic to something in the fabric of the hat?


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## Doh13 (May 3, 2015)

PhotonWrangler said:


> Could you be allergic to something in the fabric of the hat?



No i do not believe its allergies to the hat because I wear the hat all of the time with no ill effects whatever causes the pain in my forehead after using the lamp on medium power ( the setting with the wining noise) seems to be caused by the headlamp itself. I have ruled out allergies, the head Lamp being too tight on my head ,being burnt from possible hot surfaces (the part that would touch my forehead does not get hot and was not touching my forehead with the hat on). I guess i will not be able to explain why this happens if it isn't caused by em radiation i have ruled out everything else.I do know i could let someone else use it and see if the same type of thing happens to them but if there were something harmful coming from the lamp i dont think i would want to test it on another person .


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## PhotonWrangler (May 4, 2015)

Ok, thanks. Just trying to turn over every rock.


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## copiertech (Aug 11, 2015)

You have maybe irradiated your brain. Psycosis will be followed with a painful slow death.
One of the first symptoms is hallucinating that you have found an internet forum dedicated to flashlight geeks.


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## mattheww50 (Aug 11, 2015)

The EMI field have to get very high to be especially dangerous. These days an MRI usually involves a 3T magnet. IIRC that is about 1 million times the field measured in one of the previous posts.
The fields produced by a switching type supplies are many orders of magnitude smaller than the Superconducting magnets used in MRI machined, and there are very few switchers that operate above about 25kHz, and most are a lot lower. Basically it is almost impossible to radiate appreciable energy from a switching supply used in an LED light. There just isn't a lot to begin with, and the wave length is so long compared to the circuit dimensions that radiating significant EMI is nearly impossible. That means the only measurable effects are likely 'near field', the near field effect of 5 milligauss on anything except a compass are essentially nil.


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## KeepingItLight (Aug 11, 2015)

The whining sound you describe on medium (but not on high) might be inductor whine caused by PWM. If that is right, your headaches could be caused by a the flicker of PWM.

Do you know about PWM? Do you have a sensitivity to it?


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## m4a1usr (Aug 14, 2015)

KeepingItLight said:


> The whining sound you describe on medium (but not on high) might be inductor whine caused by PWM. If that is right, your headaches could be caused by a the flicker of PWM.
> 
> Do you know about PWM? Do you have a sensitivity to it?



I was thinking the same thing. To the OP (Doh13) I would suggest googling " Psychoacoustics" and do some research. There might be some form of physiological reactance due to acoustic coupling. And in particular you might have a sensitivity with this effect. Bottom line is your headlamp might not be one you want to continue to use.


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