Fenix TK40 Corrosion with Duracell Batteries

I've hardly had time to try out my two week old Fenix TK40. Last night I took it outside and it wouldn't turn on. This is why:




























The batteries were all in the correct position. The flashlight worked fine for short duration tests over a week, then was put on the nightstand and was untouched for a second week.

Is it worth trying to fix?

Overall I'm disappointed in the quality of the Fenix and probably won't buy there products again. They are not in the same class as Surefires. Not even close.

I've never had a problem with Duracells, but after doing a search on them see some people have had leak problems the last few years, so I guess quality control has dropped.

I would blame that more on the Alkaline Batteries more than I would the flashlight, this is just another reason I dont buy many lights that run on AA batteries. Id send those pictures to Duracell and see what they say, doesnt seem right that they leaked, maybe the flashlight is drawing to much current for the batteries to handle the heat.

Try hydrogen peroxide from any pharmacy. I use it all the time to wash off battery leakage. it works great most of the times

Fenix lights are of high quality. None of my four have had any problems They don't break if not used for a month.

The batteries cannot provide high current, possibly resulting to leaking. This is why rechargeables are highly recommended with the TK40.

Try cleaning some of the corrosion, and see if the light works.
If it does'nt, contact the store which you bought it from, see if they will fix or replace it.

copper tops...they are more prone to leaking than any of Duracells other variants :shakehead

To my understanding its an improperly designed seal towards the head end that gives a bit when pressure is applied from the top and MnO2 paste somehow [by stratification?] flows out and crystallizes as it drys.
I've taken apart alkalines and when they say paste then mean paste...how does it go from paste to something that flows out easily through a small hole still remains a mystery to me

That is more than likely not the lights fault. I have had alkaline batteries leak in other lights I own. Last year I had two Energizers destroy a Streamlight AA light. Streamlights warranty covered it, but it was a low priced light and was not worth the trouble of returning. Your TK40 is worth fixing! If cleaning it does not resolve the problem, you should see if the Fenix warranty covers it. Duracell may also pay for the damage done to your light. I would also buy some good NIMH batteries for your light. They will cost you more initially, but will save you tons of money in the long run. I have also never heard of NIMH AA's leaking or exploding. I only keep alkalines in my low end lights now, and will only use them in my good ones in emergencies.


Mike

Upgrade to rechargeables and say goodbye to this sort of damage and hello to better performance!

this is definitely alkaline battery problem. I had similar problem in a regular cheapo light. The alkaline corroded the contacts.

+1 on it's a battery problem.
could it be the flashlight was left on low mode accidentally?
did you loosen the head to prevent the parasitic drain?
from experience, I've stop using duracell copper top and energizer alkaline as both tend to leak (even leave it by itself on top of wooden bookshelf). I've also got into the habit of checking these gadgets that i have alkalines in once a week.
i believe the light should be fine after some cleaning work.
you should consider switching to LSD rechargeable... :thumbsup:

Using crap cells in an expensive light...

What exactly did you think was going to happen??

TangoFoxtrot said:

Overall I'm disappointed in the quality of the Fenix and probably won't buy there products again. They are not in the same class as Surefires. Not even close.

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I gotta say that's an odd conclusion to come to when it is clearly a alkaline battery failure that ocurred.

It's funny you use this to compare to Surefire - yes they are quality lights but I can't think of a Surefire that runs on alkalines, thus this result would never happen in a Surefire.

Fenix gave you the option of using cheap alkalines, you got a bad one and it leaked. Probably a good indication you should switch to NiMH and never have this problem again, and also get better performance out of the light.

I'm not going to about the quality of the Fenix TK40, it has been well established in numerous threads here. I understand your unhappiness at finding the condition of your light, but I feel your blame may be a bit misplaced. Cheap battery in expensive light = a risk of getting what you paid for (in the battery.)

Hmmm, just say the batteries are not at fault.
How in the world would the corrosion occur?...what's the basis behind the blame?

I would agree that it is the batteries. My fathter had a Nitecore D20 with a coppertop that blew out and chared the inside of the light and the pressure blew out the lens. So these batteries do have failures with no fault to the light. With the current draw the heat build up and the pressure it doesn't really surprise me that there is a battery failure. BUt in a community that helps each other out and advises when there is a problem this is the first I've heard of this issue on this light. So either no one is using alky's or there are very few problems and this is just a freak accident. Fenix is a very good company I loved my TK40 except for the size. Also duracell warranties there batteries don't they. I think they will replace whatever there batteries destroy if the company you bought the light from does not.

strinq said:

Hmmm, just say the batteries are not at fault.
How in the world would the corrosion occur?...what's the basis behind the blame?

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The OP did not say whether all 8 coppertops were new when he put them in the light - if they weren't that could be the problem, that and the fact that they are alkalines. Whether using 4 cells or 8 in this light, they all need to be as balanced as possible, i.e. new from the same package, etc. Also best to avoid alkalines entirely unless there is no choice.

This light uses 8 AA batteries, in two parallel banks of four. Whenever you have more than one cell in a series, there is a chance of reverse charging as the energy gets fully drained, especially if one of the cells has significantly less capacity than the others. The more cells in series, the higher the risk of reverse charging. Any battery may have problems from reverse charging, but an alkaline is most likely to leak under these conditions.

Also, this being an 8 cell light, there is always the chance of inserting a cell backwards, again resulting in reverse charging.

One of the cells could have been dropped, compromising its seal, making it more likely to leak. Or just defective in some other way.

What probably happened here is that one of the coppertops was either highly depleted compared to the others, or possibly damaged or defective in some way, and the light was not locked out when put away. With the small parasitic drain and unbalanced cells, this resulted in the leak.

The TK40 is not a load it and forget it kind of light; you need to be aware of using good quality balanced cells, and locking out the light when put away. Also avoid alkalines

A lifetime of advertising meets gravity

Good luck with the repair

You lucky you can still pull the batteries out of the light, my Duracell batteries stuck in my M@g light that don't come out.

I use Energizer Ultra Lithiums. No problem so far. I love my TK40.

I don't know where you're located, but this comes from the Duracell website: Duracell Battery Guarantee

If you're not completely satisfied with a DURACELL Product,

All DURACELL Batteries are guaranteed against defects in material and workmanship. Should any device be damaged by these batteries due to such defect, Duracell will repair or replace it (at Duracell's option) if it is sent with the batteries, postage prepaid to:

Duracell
Berkshire Corporate Park
Bethel, CT, 06801 U.S.A.
Att: Consumer Dept.

Those pics are hard to look at... anyway, I just bought 8 eneloops coming my way soon... but still saving for a TK40, no way am going to put alkies in there or any of my lights.

Well I say it's definitely Fenix that is faulty, i can buy that piece of crap from you, is 50$ ok? :naughty: