Significant 4XAA Battery short in Fenix headlamp

TheMediocrePirate

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I woke up early last week to catch a flight to Washington state for a quick mountaineering expedition up to the top of Mt. Ranier. In my final preparations before leaving the house, I put in 4 brand new duracell AAs in my Fenix HP25 which I've had it for a while. So far it's been reliable, and has only seen occasional use on the odd night time search & rescue call at the rescue squad. After swapping out the batteries, I tested it to see if everything was in order, and tossed it into my carry on alongside of my heavier Arc'teryx jackets and didn't think anything of it. About six hours later, I reached into my backpack to get out a snack and was baffled to feel the interior of my bag feel VERY warm. I quickly found that the battery pack of my headlamp was very hot, and saw that the outside was starting to melt and deform. I opened the battery compartment to find all the cells had started to char and were too hot to the touch. Having no other options, I dumped out the cells on the floor where they remained too hot to touch for a further 10 or so minutes.

I am EXTREMELY happy that I found this issue when I did. Had I not discovered this issue, I would have walked onto my flight 30 minutes later with an active fire hazard on a packed commercial flight. Thankfully, I didn't have to have that conversation with Airline staff/the TSA, and the rest of my items including my main outer-layers needed to climb Rainier came out unscathed. I also had packed my trusty Black Diamond Ion as a backup, so I didn't have to learn how to climb by braille. Upon getting back home last Friday, I put in new cells, and despite deformed springs that no longer really contact the batteries, the light still turns on. I however did not leave the batteries in long enough to find out if they got warm.

Has this ever happened to anyone else? Anyone have any speculation as to what might have caused this issue? Unfortunately I'm still waiting to hear back from Fenix despite having sent 2x emails and one voice mail over the course of the last week. Duracell responded within an hour, and has been extremely helpful and willing to help figure out the cause.

20180805_085225 by Nico, on Flickr

20180805_084726 by Nico, on Flickr

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archimedes

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... moved to Smoke & Fire - Hot Cells & Close Calls ...

Thank you for your report above and, especially, including photos
 

Gauss163

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Yes, such meltdowns have happened to many others, e.g. from Amazon reviews

proton32060 said:
1.0 out of 5 stars, Lasts about a Year, By proton32060 on October 22, 2015, Color: Yellow, Verified Purchase

These are very nice headlamps however you should be aware they will only last about a year with occasional use.

I have three of them and two have failed in about a year. They don't burnout but instead form a dead short somewhere in the headlamp unit. This occurred on two of the ones I own.

At some point you go to turn them on and they work for a second and blink off. You check the batteries and they are either EXTREMELY hot or dead. If you put new batteries in because the others were dead then they get extremely hot.

It is a real shame because these are really nice units- extremely bright and easy to use.
My guess is either the switch they use or the dimmer circuit can't take the current the batteries put through it. It works for a while and finally fries forming the dead short.
At that point the unit is gone- there is no way to repair it.

Compared to most headlamps this is a very expensive unit and in my opinion should last a lot longer and be more well made.

With what these cost it should be made much better quality than this.

If you are going to spend this much it might be better to spend a little more and get the Magnus Atlas with a Lifetime Warranty.

The Fenix is going to break sooner or later depending on how much you use it
Better to buy something they will replace instead of throwing your expensive headlamp in the garbage.

And in a comment on the above review:

bowlingballhead said:
Same exact thing just happened to mine. Bought new in July 2016 and just got the dead battery/new hot batteries failure. LAME, cause I really liked the headlamp. Now have to wade through a see of headlamps to find a new one. Should have read your review, lol.

And another Amazon reviewer wrote

Hacksaw said:
I do believe the one I purchased may have been defective as the buttons didn't want to work some of the time and it randomly stopped working one night and when I opened the battery compartment, some of the springs were red hot and the batteries were sparking.

And another
update -- the unit spontaneously failed; when switching it on, it clearly had developed a dead short, with the batteries getting HOT and the smell of burning insulation. No idea what happened, and the unit had been used and stored with care.

and another
I work as a contracted mechanic at night and use this light every night at work and at first the light worked flawlessly but 8 months in the springs in the battery pack to hold the batteries against the positive contacts have compressed to the point where they no longer hold the batteries firm. The light would operate sporadically and one night the battery pack got too hot to touch and burned up.
I recommend that you report dangerous products like this to the CPSC = Consumer Products Safety Commission via the website SaferProducts.gov. It's quick and easy and may end up saving someone's life.
 
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TheMediocrePirate

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... moved to Smoke & Fire - Hot Cells & Close Calls ...

Thank you for your report above and, especially, including photos
Sorry for starting this thread in the wrong place! I appreciate you finding a better home for it!

Yes, such meltdowns have happened to many others, e.g. from Amazon reviews...
Thanks for digging those up! It really starts to sound like it's quite the issue with that model. I politely brought up that fact to the Fenix service guy who finally responded to my e-mail(s), and he was very insistent it couldn't possibly be the light but rather "something called Thermal Runaway...". To me it just seems like too much of a coincidence this "rare occurrence" seems to happen so often in the same fashion, and in the same product.
 
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pc_light

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..."something called Thermal Runaway...". To me it just seems like too much of a coincidence this "rare occurrence" seems to happen so often in the same fashion, and in the same product.
Glad you caught it in time and that no further damage resulted. +1 about reporting the light to CPSC to establish a record, in case it's a design flaw rather than random accident. I'd also check out battery holder and wiring for possible shorts (i.e., "thermal runaway".)
 

MikeSalt

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Since Fenix are proving to be so unhelpful, I would allow Duracell to examine the light and produce a technical report on the failure reason, then go back to Fenix with that report.
 

LittleBill

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i have never used alkaline in my hp10's fenix doesn't even recommend them, i have 2 headlamps both have over 500+ hours on them, 0 issue with eneloops, my opinion is the light got turned on turbo or something and overheated the cells.

stop using alkaline.
 

Gauss163

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^^^ But we don't know if the reviewers were using alkalines. If - as surmised - the electronics shorted the cells then the meltdown may be worse using cells like NiMH with higher current capability (depending on quality, i.e. design of venting, etc).

Worth mention is that Fenix ships the HP25 with alkalines ("Pairdeer" brand) - see the first photo, and their manual says that alkalines are "usable" but recommends NiMh (2nd photo).

qBzIp.png

N0KPE.png
 

TheMediocrePirate

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...my opinion is the light got turned on turbo or something and overheated the cells...

The way the light is designed, you have to angle the head out in order to depress the buttons. All though the light wasn't on when I pulled it out of my bag, while unlikely, it is still a possibility.
 

Monocrom

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I have to agree with MikeSalt. Duracell is willing to work with you, while Fenix is dragging its feet here.
 
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