# Fenix TK40 Corrosion with Duracell Batteries



## TangoFoxtrot (Jul 6, 2009)

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.


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## FlashlightsNgear.com (Jul 6, 2009)

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.


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## alpg88 (Jul 6, 2009)

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


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## rockz4532 (Jul 6, 2009)

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.


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## Illum (Jul 6, 2009)

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


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## mikekoz (Jul 6, 2009)

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


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## Yucca Patrol (Jul 6, 2009)

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


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## picard (Jul 6, 2009)

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


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## rookiedaddy (Jul 6, 2009)

+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:


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## Marduke (Jul 6, 2009)

Using crap cells in an expensive light...

What exactly did you think was going to happen??


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## jahxman (Jul 6, 2009)

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.


 
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.)


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## strinq (Jul 6, 2009)

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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## Viper715 (Jul 6, 2009)

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.


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## jahxman (Jul 6, 2009)

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?


 
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


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## thedeske (Jul 6, 2009)

A lifetime of advertising meets gravity 

Good luck with the repair


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## glockboy (Jul 6, 2009)

You lucky you can still pull the batteries out of the light, my Duracell batteries stuck in my [email protected] light that don't come out.


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## recDNA (Jul 6, 2009)

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


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## deKatt (Jul 6, 2009)

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.


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## 1anrm (Jul 6, 2009)

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.


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## Egsise (Jul 6, 2009)

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


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## Kiessling (Jul 6, 2009)

Given the fact that we know about the problems of alkaline batteries, putting 2x4 in a series arrangement with high draw is a desigbn flaw, or, at least advertising the use of alkaline batteries in such a set-up is, I think. 

There's the same reverse charging problem with lithiums. They just don't leak. They explode 

bernie


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## TangoFoxtrot (Jul 6, 2009)

They were brand new batteries right out of the box. They were the only batteries I had on hand and I wanted to test it since it just arrived. I put them in carefully and correctly. I briefly tested the light every couple of days for a week then got too busy to get back to it for another week and then this. I looked at rechargeables locally but they want $10 a cell so haven't picked any up yet. 

The Fenix is too lightly built in my opinion. I was disappointed the moment I picked it up. My Surefire lights are made of thicker metal and have a positive solid feel of quality when I click the switch. The Fenix feels cheap. I had also ordered a PD30 and it feels cheap too. I don't think it will last years like my Surefire already has. Even a $20 2-cell Maglite looks and feels more solid and better made than the flemsy TK40. I won't be buying anything made by Fenix again based on build quailty, even if the Duracell batteries were at fault.


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## woodrow (Jul 6, 2009)

recDNA said:


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


 


Kiessling said:


> Given the fact that we know about the problems of alkaline batteries, putting 2x4 in a series arrangement with high draw is a desigbn flaw, or, at least advertising the use of alkaline batteries in such a set-up is, I think.
> 
> There's the same reverse charging problem with lithiums. They just don't leak. They explode
> 
> bernie


 
Wow, I was going to buy another tk40 and stock it with lithium AA's. Small chance of explosion though..... On the bright side--- it would make for a really cool cpf thread! " My TK40 Exploded....lots of pics!" would most likely get thousands of hits...




lol


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## recDNA (Jul 6, 2009)

Kiessling said:


> Given the fact that we know about the problems of alkaline batteries, putting 2x4 in a series arrangement with high draw is a desigbn flaw, or, at least advertising the use of alkaline batteries in such a set-up is, I think.
> 
> There's the same reverse charging problem with lithiums. They just don't leak. They explode
> 
> bernie


 
Even ordinary non-rechargeable Lithiums? If so I'll switch to Duraloops when these wear down.


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## TangoFoxtrot (Jul 6, 2009)

There is also corrosion in the front cap. Is this anything to be concerned about?




















That's about the best I can do with my cheapo camera.


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## jahxman (Jul 6, 2009)

You should probably get Duracell to replace your light for you; you can probably clean most of that up but why not just get the thing replaced? Duracell has a warranty that should cover - although I don't know what they'll say when you tell them how much the light costs....



TangoFoxtrot said:


> The Fenix is too lightly built in my opinion. I was disappointed the moment I picked it up.... The Fenix feels cheap. Even a $20 2-cell Maglite looks and feels more solid and better made than the flemsy TK40. I won't be buying anything made by Fenix again based on build quailty.


 
Well, it is clear your mind is made up, however have you seen this thread? 

:https://www.candlepowerforums.com/threads/233856

In it the TK40 withstands some pretty horrific abuse and keeps working fine... If nothing else it might give you pleasure to see a reviled Fenix abused in such a way. :sick2:


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## Bushman5 (Jul 6, 2009)

not the lights fault in any way shape or form. Contact DURACELL and ask for replacement batteries and money for damages to your light. They WILL pay you for any damages caused by their batteries. 

I left coppertops in a maglite and they leaked. Got a free maglite and a box of C cells from Duracell.

By the way, TK40 = ONE TOUGH LIGHT............. please read here: https://www.candlepowerforums.com/threads/233856


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## kwkarth (Jul 6, 2009)

TangoFoxtrot said:


> They were brand new batteries right out of the box. They were the only batteries I had on hand and I wanted to test it since it just arrived. I put them in carefully and correctly. I briefly tested the light every couple of days for a week then got too busy to get back to it for another week and then this. I looked at rechargeables locally but they want $10 a cell so haven't picked any up yet.
> 
> The Fenix is too lightly built in my opinion. I was disappointed the moment I picked it up. My Surefire lights are made of thicker metal and have a positive solid feel of quality when I click the switch. The Fenix feels cheap. I had also ordered a PD30 and it feels cheap too. I don't think it will last years like my Surefire already has. Even a $20 2-cell Maglite looks and feels more solid and better made than the flemsy TK40. I won't be buying anything made by Fenix again based on build quailty, even if the Duracell batteries were at fault.



You are certainly free to do as you wish, but in all fairness to fair and balanced reporting, check out this thread about the TK40 durability;

https://www.candlepowerforums.com/threads/233856

Cheers,
k


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## AusKipper (Jul 6, 2009)

TangoFoxtrot said:


> The Fenix is too lightly built in my opinion. I was disappointed the moment I picked it up.



Umm, so was I, untill I saw this thread:
https://www.candlepowerforums.com/threads/233856

It was run over with a car, boiled, towed down a road and dropped repeatedly without failing. There is nothing wrong with the build quality of most Fenix lights in my opinion. I challenge you to find a surefire built as heavily as the Fenix TK20 

Batteries can leak and destroy both cheap torches, and expensive torches. The torch is not at fault. (they can also leak and destroy anything else, including clocks, cameras, GPS's etc etc of course..). If rechargeable are $10 a piece in your area I suggest you order some in from somewhere...

Anyway, good luck with cleaning out your torch. If you cant fix it Duracell should replace it.

Hopefully you learn from your mistake and immediately go and order a whole stack of Eneloops and replace every alkaline you own with them.


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## mendhammarsh (Jul 6, 2009)

I recently had a brand new Duracell single cell alkaline battery leak. The expiration date on the battery is Mar 2015. I was fortunate that I inspected the flashlight before any damage was done. Perhaps there is a quality control issue with this batch.

You must contact Duracell and make them aware of your issue.

Good Luck.


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## dano (Jul 6, 2009)

AusKipper said:


> Umm, so was I, untill I saw this thread:
> https://www.candlepowerforums.com/threads/233856
> 
> It was run over with a car, boiled, towed down a road and dropped repeatedly without failing. There is nothing wrong with the build quality of most Fenix lights in my opinion. I challenge you to find a surefire built as heavily as the Fenix TK20



What do I get if I have a SF that's as "heavy" as a TK20?

Seriously, though, doesn't the TK40 have a decent amount of parasitic drain when off? A high enough drain will kill the alkalines and eventually cause leakage.

I'd also suggest contacting Duracell: http://www.duracell.com/company/contact.asp?id=58&

-dan


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## John_Galt (Jul 6, 2009)

Another reason I never use my LD20 on turbo (ok, so not for more than a minute or two at a time ). I have not had a chance to convince my parents of the need to purchase Eneloops, or even Energizer lithium AA's. 
This light is not crap, it just was not designed to use Alkaline AA's on Turbo mode. Drawing that much current through a type of cell chemistry that is notorious for leaking, unable to handle that high a current, etc. is just an accident waiting to happen. You waited, it happened. 
Send a message to Duracell, with pics of the damage, and go and buy yourself a set of Eneloops. Won't happen again.


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## Lightcrazycanuck (Jul 6, 2009)

John_Galt said:


> Another reason I never use my LD20 on turbo (ok, so not for more than a minute or two at a time ). I have not had a chance to convince my parents of the need to purchase Eneloops, or even Energizer lithium AA's.
> This light is not crap, it just was not designed to use Alkaline AA's on Turbo mode. Drawing that much current through a type of cell chemistry that is notorious for leaking, unable to handle that high a current, etc. is just an accident waiting to happen. You waited, it happened.
> Send a message to Duracell, with pics of the damage, and go and buy yourself a set of Eneloops. Won't happen again.


 
+1

Could not have said it better myself.:twothumbs:twothumbs:twothumbs


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## AusKipper (Jul 6, 2009)

dano said:


> What do I get if I have a SF that's as "heavy" as a TK20?



Some Brownie points?? 

BTW when I said heavy, I meant thickness of the battery wall, I in no way meant either overall quality or overall weight.

I am by no means stating Fenix's are of a Higher quality than Surefire, before I start that war 

And yes, there are some small quality issues with Fenix, as with any make, such as the battery drain in the TK40, non-anodised threads, and it seems the QC on their tail clicker (for the TK10/11/20-series clickie) MAY be lacking a touch.

But still, overall, definitely good lights in my opinion.


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## jirik_cz (Jul 7, 2009)

dano said:


> Seriously, though, doesn't the TK40 have a decent amount of parasitic drain when off? A high enough drain will kill the alkalines and eventually cause leakage.
> -dan



The parasitic drain is around 0,4mA. That definitely should not cause the leakage.


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## strinq (Jul 7, 2009)

You know what, I would actually love to see a surefire go through the same tests that the TK40 went through. 

The whole 'fact' that a lot of people complain that it's too light and that the body is too thin etc and at the same time the TK40 can withstand all that abuse actually shows how fantastic the engineering and design was.

To be able to be light AND bloody strong. 
If surefires have to be thick and heavy to withstand the same abuse then in reality the fenix is better no?


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## mikekoz (Jul 7, 2009)

I thought the TK40 body was kind of thin at first, but when I read about the torture test, all thoughts of the light being fragile went out the window! Besides, some folks are saying that the light is too heavy with the batteries in it as it is. If they made the body as thick as some of their other lights, it would be the BA40...Boat Anchor 40!!!

Mike


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## Outdoors Fanatic (Jul 7, 2009)

Parasitic drain + Alkaline cells = *FAIL!*

That's why I only use CR123s or quality Li-Ions. I've had many expensive electronic devices completely ruined by alkaline batteries, today I avoid them like the plague.


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## MrGman (Jul 7, 2009)

I think where one lives and relative levels of humidity plays a big part into that as well. Since no one keeps track of such things, hard to quantify. But in general I concur. I don't put Alkaline in important things that I want to work when I need them to work. G.


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## kwkarth (Jul 7, 2009)

Outdoors Fanatic said:


> Parasitic drain + Alkaline cells = *FAIL!*
> 
> That's why I only use CR123s or quality Li-Ions. I've had many expensive electronic devices completely ruined by alkaline batteries, today I avoid them like the plague.



I think I'm becoming a believer. About two months ago, I was going through some of my lights, just to inventory them, clan them up, etc. and two oldies had been completely ruined by alkies. Fortunately it was only a couple of Maglights (5D & 3D) and an old 2AA cheapie. I fiddled for a couple weeks trying to clean them up, and finally tossed them.


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## kwkarth (Jul 7, 2009)

strinq said:


> You know what, I would actually love to see a surefire go through the same tests that the TK40 went through.
> 
> The whole 'fact' that a lot of people complain that it's too light and that the body is too thin etc and at the same time the TK40 can withstand all that abuse actually shows how fantastic the engineering and design was.
> 
> ...



I used to be a die hard Surefire supporter, but somewhere along the way their pace of innovation seems to have stalled out while they've been overtaken and left in the dust by a bunch of upstarts. I used to not even look at non Surefire lights. I've got quite a few of their incandescents and several of their early led lights, but eventually it made no sense to keep buying old technology at 3x the price of its worth.

Surefire! GYAT! We need you back!


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## HKJ (Jul 7, 2009)

Outdoors Fanatic said:


> Parasitic drain + Alkaline cells = *FAIL!*



Not really, there exist a lot of equipment that put a small drain on alkaline cells, sometimes they leak, but mostly they do not.


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## Outdoors Fanatic (Jul 7, 2009)

HKJ said:


> Not really, there exist a lot of equipment that put a small drain on alkaline cells, sometimes they leak, but mostly they do not.


Obviously your mileage may vary, but in my personal experience, everytime I left alkaline cells (all brands, all sizes, no exceptions) in my gear they leaked like a SOB. I don't want nor need to have to deal with this crap in my life again. It's a choice I gladly made. It's Lithium or li-ion all the way to me. I don't even buy gears that don't take them.


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## HKJ (Jul 7, 2009)

Outdoors Fanatic said:


> Obviously your mileage may vary, but in my personal experience, everytime I left alkaline cells (all brands, all sizes, no exceptions) in my gear they leaked like a SOB. I don't want nor need to have to deal with this crap in my life again. It's a choice I gladly made. It's Lithium or li-ion all the way to me. I don't even buy gears that don't take them.



I did not object to the fact that alkaline cells leak, but to you statement that a small drain makes them leak. If that was the case you would not have a leak in a maglite, but lots of leaks in thermometers, watches etc..
The cases where I have seen leaks has been in equipment without any drain.


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## Illum (Jul 7, 2009)

mikekoz said:


> If they made the body as thick as some of their other lights, it would be the BA40...Boat Anchor 40!!!
> 
> Mike



your thinking what I'm thinking?
DM51's https://www.candlepowerforums.com/threads/177787

really though, with a bit of knowledge in structural engineering you can form a piece of aluminum thin enough to be dented by your finger into something that can take several times the weight exerting on it...


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## strinq (Jul 7, 2009)

Outdoors Fanatic said:


> Obviously your mileage may vary, but in my personal experience, everytime I left alkaline cells (all brands, all sizes, no exceptions) in my gear they leaked like a SOB.


 
Wow. Everytime? That must really suck.
I've only had 1 or is it 2? cells that ever leaked on every electronic equipment i've used, lights, remote controls etc etc.
Still think that it's still a not bad source of energy. But if I have the choice, I wouldn't risk it in really expensive equipment.


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## Rexlion (Jul 7, 2009)

Definitely a Duracell failure and not a Fenix failure! I'm sure Duracell will take care of it for you. 

I had some Energizer alkalines leak after being in my programmable thermostat for about 4-5 years, so I sent the thing to Energizer and they sent me replacement money to buy another thermostat... although they did point out that I was supposed to replace batts more often than that. See, if a battery company is this good about warranteeing their product, you have nothing to worry about.

I feel the same as an earlier poster: if you really don't want the light or the hassle of dealing with this, PM me and I'll be happy to pay you to send it to me. We'll both be happy.


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## Outdoors Fanatic (Jul 7, 2009)

strinq said:


> Wow. Everytime? That must really suck.
> I've only had 1 or is it 2? cells that ever leaked on every electronic equipment i've used, lights, remote controls etc etc.
> Still think that it's still a not bad source of energy. But if I have the choice, I wouldn't risk it in really expensive equipment.


Yes, everytime! 

Here is a list of some of my equipment that got trashed by alkaline cells: 

- R/C Radio Control transmitters and speed controls
- GPS and Beacon locator devices
- 2-Way Radios
- Portable Water Purifiers
- Flashlights
- Digital Cameras

I've already lost more that 3k in damage due to this crappy chemistry. So don't even ask me if I think it's not a bad source of energy...


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## Marduke (Jul 7, 2009)

I think you are confused. It is indeed a poor chemistry, but not for the reason you mentioned. The drain in the TK40 is not nearly high enough to cause death in the timeframe provided.

Low drain is actually the only practical use for alkaline.


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## Outdoors Fanatic (Jul 7, 2009)

Marduke said:


> I think you are confused. It is indeed a poor chemistry, but not for the reason you mentioned. The drain in the TK40 is not nearly high enough to cause death in the timeframe provided.
> 
> Low drain is actually the only practical use for alkaline.


All those things destroyed by alkies were all low-drainage devices... So not practical or safe for those either.


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## Marduke (Jul 7, 2009)

Well when you run them all the way dead...

And those devices are fairly high drain electronics.


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## kramer5150 (Jul 7, 2009)

I've said it before and it definitely needs repeating....

*DO NOT USE ALKALINES IN ANY LIGHT YOU INTEND TO KEEP.*

If you do, do not store the light/item loaded for any duration of time. Immediately remove the cell after use. I have hand BRAND NEW kirkland AA (Duracell rebrand) sitting on top of my keyboard leak. Heres my list of lost/irrecoverable items that AA alkalines killed:

-$185 Airtronics transmitter for my RC-Cars
-$172 denon Home theater remote (that was the price to replace it with an identical OEM)
-Various portable walkman cassette players and CD players ($100 approximate $$ spent for these items)
-Various kid toys, usually under $20 each.

I have learned the hard (IE expensive) way, its LSD NiMH for me for everything.

This is an enthusiast forum, members invest HUGE $$$ in this hobby... to openly recommend or suggest Alkalines in any CPF-worthy light is doing the member a disservice.


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## kramer5150 (Jul 7, 2009)

Furthermore...
Duracell and energizer offer a 100% $$$ back guarantee. They will refund you the full $$ amount for any product their batteries destroy. This is the financial equivalent of an open statement "We already know our products are failure prone and destructive.... use/purchase at your own risk."

This is not the fault of Fenix, their products are top-notch.... its the Alkaline chemistry that failed. (although I think Fenix is making a HUGE mistake marketing this light as Alkaline compatible).

A Surefire would also suffer the same fate. SF chooses not to make a AA light... and I think this is the reason. It would be a costly endeavor to offer a lifetime part replacement warranty on anything that accepts alkaline cells.

the TK40 is probably one of the most over-built designs I have ever seen/held...
https://www.candlepowerforums.com/threads/233856


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## NeonLights (Jul 7, 2009)

IMO it is partly the light's fault and partly the batteries fault, it could be also said it is partly the manufacturer's fault and the end-user's fault. Over the past 20 year or so, I've lost many Maglites filled with alkalines to battery leakeage, Duracell, Energizer, Rayovac, and one or two of the cheapie brands have all leaked and welded themselves in my Mags, essentially destroying them. IIRC I've lost a couple other metal-bodied flashlights to leaking alkalines as well, although I don't recall ever losing a plastic bodies flashlight to leaking alkalines.

Maybe someone more knowledgeable about the physics of it all can chime in, but there seems to be something about alkaline batteries and metal bodied flashlights that is always a bad combination in the long run, and occasionally in the short term as well. Case in point, I opened up a drawer in my garage I had forgotten about for 4-5 years. It had three alkaline powered flashlights in it, two were plastic bodied, one was a Maglite. All the alkaline batteries were well past their expiration date, and quite possibly from the same batch of batteries, but the only flashlight that had leaking batteries (and was destroyed) was the Mag. The other two lit up even though the batteries were years past their expiration date and hadn't been turned on in at least 4-5 years. 

The majority of the fault probably lies with the battery manufacturer because the batteries were very fresh and had only been in use for a couple of weeks, but IME alkalines and any metal-bodied flashlights are a potentially bad combination unless the batteries are checked and/or replaced very frequently. It typically isn't a question of if the alkaline batteries will leak in a metal flashlight, but when. 

This (and the user interface) is one of the things holding me back from buying a Fenix TK40, the battery issue. Lithiums are too expensive to feed the thing, and buying and maintaining 8 matched NiMH batts is more than I want to mess with, and feeding it 8 alkalines is too risky, in case I leave it somewhere for any length of time.


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## Marduke (Jul 7, 2009)

It's not that metal body lights are more likely to cause a leak, the acid just makes a bigger mess when it corrodes the aluminum.


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## NeonLights (Jul 7, 2009)

Marduke said:


> It's not that metal body lights are more likely to cause a leak, the acid just makes a bigger mess when it corrodes the aluminum.


I guess it is just very strange/coincidental then, that I can't recall ever having had a plastic flashlight have leaking alkalines (and I've had quite a few plastic/nylon flashlights), yet I've lost many metal bodied flashlights to leaking alkalines.


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## MrGman (Jul 7, 2009)

NeonLights said:


> I guess it is just very strange/coincidental then, that I can't recall ever having had a plastic flashlight have leaking alkalines (and I've had quite a few plastic/nylon flashlights), yet I've lost many metal bodied flashlights to leaking alkalines.


 

I had a plastic flashlight where the batteries leaked and corroded the spring terminals to the batteries on the deep end. I had a motordrive to a camera that was a plastic housing and the batteries started leaking in there as well. 

Alkaline is by its very name a caustic material that doesn't like to stay in its container. Give it half a chance and your in Corrosion City, an ugly place for sure.


----------



## kramer5150 (Jul 7, 2009)

NeonLights said:


> I guess it is just very strange/coincidental then, that I can't recall ever having had a plastic flashlight have leaking alkalines (and I've had quite a few plastic/nylon flashlights), yet I've lost many metal bodied flashlights to leaking alkalines.



my Denon remote and my daughters Disney princess light were both plastic bodied. The cells corroded the contact springs. Alkaline is an equal opportunity destroyer... give it a chance and it will puke its ghastly guts all over anything in its path, regardless of material.


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## MorePower (Jul 7, 2009)

Marduke said:


> It's not that metal body lights are more likely to cause a leak, the acid just makes a bigger mess when it corrodes the aluminum.



It's not acid, it's base (potassium hydroxide).


----------



## bob4apple (Jul 7, 2009)

> Duracell and energizer offer a 100% $$$ back guarantee. They will refund you the full $$ amount for any product their batteries destroy. This is the financial equivalent of an open statement "We already know our products are failure prone and destructive.... use/purchase at your own risk."



*EXACTLY CORRECT*
Duracell batteries destroyed a remote control of mine and had to pay up. Now that there are NIMH eneloops and others like them, it's just plain dumb to use alkalines for *anything*!


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## recDNA (Jul 7, 2009)

NeonLights said:


> IMO it is partly the light's fault and partly the batteries fault, it could be also said it is partly the manufacturer's fault and the end-user's fault. Over the past 20 year or so, I've lost many Maglites filled with alkalines to battery leakeage, Duracell, Energizer, Rayovac, and one or two of the cheapie brands have all leaked and welded themselves in my Mags, essentially destroying them. IIRC I've lost a couple other metal-bodied flashlights to leaking alkalines as well, although I don't recall ever losing a plastic bodies flashlight to leaking alkalines.
> 
> Maybe someone more knowledgeable about the physics of it all can chime in, but there seems to be something about alkaline batteries and metal bodied flashlights that is always a bad combination in the long run, and occasionally in the short term as well. Case in point, I opened up a drawer in my garage I had forgotten about for 4-5 years. It had three alkaline powered flashlights in it, two were plastic bodied, one was a Maglite. All the alkaline batteries were well past their expiration date, and quite possibly from the same batch of batteries, but the only flashlight that had leaking batteries (and was destroyed) was the Mag. The other two lit up even though the batteries were years past their expiration date and hadn't been turned on in at least 4-5 years.
> 
> ...


 
It takes about 5 minutes to get used to the UI on a TK40. I prefer a bezel ring with a stop at turbo (no 360) but only so I can set the mode before I turn the flashlight on. I'm not crazy about loose bezel vs. tight bezel either. I like a tight flashlight with a bezel the switches between modes. I've never seen one designed the way I would like it along with a forward clicky.


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## Kwanon13 (Jul 7, 2009)

There have been issues with this light. Do a search for "tk40 returns". I remembered 4-Sevens mentioning being busy handling these returns while trying to launch his new line.


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## marc123 (Jul 8, 2009)

Kwanon13 said:


> There have been issues with this light. Do a search for "tk40 returns". I remembered 4-Sevens mentioning being busy handling these returns while trying to launch his new line.


 
I read what 4sevens said but I have not seen the negative posts on this forum to back it up. I think it must be the average Joe buying the TK40 with no idea about using the right cells and putting mixed alkaline cells in with different brands and different capacity and levels of charge? Any thoughts? 

I just ordered a TK40....


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## cujet (Jul 8, 2009)

At the show last weekend the Fenix dealer told me that the 40 draws power all the time. So, according to him, you must unscrew the tailcap a bit, when storing the light. 

So, if true, the original post may have been correct, the light could be at fault by draining the batteries fully, thereby promoting a leak or two.


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## kwkarth (Jul 8, 2009)

cujet said:


> At the show last weekend the Fenix dealer told me that the 40 draws power all the time. So, according to him, you must unscrew the tailcap a bit, when storing the light.
> 
> So, if true, the original post may have been correct, the light could be at fault by draining the batteries fully, thereby promoting a leak or two.



Like me, it sounds like that dealer knew just enough to be dangerous.

What a pickle... While it's a great idea to be able to offer a high performance torch that uses a ubiquitous power source such as AA cells, :twothumbs it's a real shame that those cells aren't up to the challenge...:mecry:We have two problems here. We have a flashaholic level performing torch, now attracting the average Joe because it uses a power source that "Joe" feels comfortable with, but really, understands little about.

In the hands of a savy and conscientious user, the TK40 will most likely be trouble free, but in the hands of the average user, it's trouble waiting to happen. 

Fenix should publish a statement saying that although the TK40 is capable of running on alkaline batteries, the use of them is not recommended, and if indeed, the flashlight is damaged by the use of any chemistry other than lithium, nicad, or nickel metal hydride, or by improper (backwards) insertion of any cell, regardless of chemistry, the seller cannot accept any responsibility for damage. Another paragraph should be added with discussion about the dangers of using unbalanced / unmatched cells.

Secondly, Fenix should design and release a battery tube using a more appropriate power source such as 123 cells and their rechargeable ilk. This new battery tube should become the primary tube sold with the light and the AA tube should be an extra cost option packaged with the above disclaimers. 

Maybe they could re-package the AA version light with Eneloops, or lithium primaries.

Anyway, kudos to Fenix for designing a light for everyman, but condolences for the fact that it can use the ubiquitous Alkaline AA.

I have one on order from 4Sevens...


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## recDNA (Jul 8, 2009)

cujet said:


> At the show last weekend the Fenix dealer told me that the 40 draws power all the time. So, according to him, you must unscrew the tailcap a bit, when storing the light.
> 
> So, if true, the original post may have been correct, the light could be at fault by draining the batteries fully, thereby promoting a leak or two.


 
From what I've been told it is better to unscrew the head...and not enough power is being drained to excuse the battery leakage. I threw away a 3 D cell Maglite before joining this forum because the alkalines in it burst and I couldn't get them out. Now I know I should have sent the flashlight to Duracell but I didn't know that when I threw it away! My point is that alkalines sometimes spring leaks regardless of what you put them in. The TK40 is too expensive to risk it....but in an emergency I would use alkalines in a heartbeat and be glad of their ready availability. You can scramble to the local drugstore and hope they have some "camera" batteries left! 

I know some of you store dozens of CR123's for such emergencies but I don't. I carry two (Energizer Ultra Lithiums)in my car and my wife's car and 4 in the fridge...then it's AAA all the way (one set of 8 Ultra Lithiums for the TK40 then it's on to alkalines). I also have more Maglites than I care to admit with a big stock of D cells.


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## recDNA (Jul 8, 2009)

"Anyway, kudos to Fenix for designing a light for everyman, but condolences for the fact that it can use the ubiquitous Alkaline AA.

I have one on order from 4Sevens..."

LOL

I think you'll like it. It's my fav. I'm used to a 2 D cell sized Maglite and so it's just the right size for me.


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## alpg88 (Jul 8, 2009)

idk if parasitic draw couses alkies to leak than my aa maglite with iq switch (it too draws power all ther time, little red light in the switch always blinks) should be leaking all the time, yet it never did. yet.


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## thedeske (Jul 8, 2009)

kwkarth said:


> Fenix should publish a statement saying that although the TK40 is capable of running on alkaline batteries, the use of them is not recommended, and if indeed, the flashlight is damaged by the use of any chemistry other than lithium, nicad, or nickel metal hydride, or by improper (backwards) insertion of any cell, regardless of chemistry, the seller cannot accept any responsibility for damage. Another paragraph should be added with discussion about the dangers of using unbalanced / unmatched cells.



They do warn several times about leakage on page 5 of the manual but the language is loose. Unbalanced/unmatched is there in the form of 'State Of Charge'

16 NIMH and a charger required to operate? That wouldn't get past the sales department


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## kwkarth (Jul 8, 2009)

thedeske said:


> They do warn several times about leakage on page 5 of the manual but the language is loose. Unbalanced/unmatched is there in the form of 'State Of Charge'



Well, that proves "it." 

One can never underestimate the proclivity of the buying public to;


Ignore any written or spoken instructions.
Ignore any written or spoken warnings
Manage to "do" exactly the wrong thing with respect to safe and proper operation of the purchased product.
Place blame for items 1-3 above directly upon the shoulders of the manufacturer/seller of the product.


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## tebore (Jul 8, 2009)

NeonLights said:


> I guess it is just very strange/coincidental then, that I can't recall ever having had a plastic flashlight have leaking alkalines (and I've had quite a few plastic/nylon flashlights), yet I've lost many metal bodied flashlights to leaking alkalines.



I lost a lot of toys as a kid and now as an adult to leaking alkaline batteries. They were all plastic.


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## jirik_cz (Jul 8, 2009)

cujet said:


> At the show last weekend the Fenix dealer told me that the 40 draws power all the time. So, according to him, you must unscrew the tailcap a bit, when storing the light.
> 
> So, if true, the original post may have been correct, the light could be at fault by draining the batteries fully, thereby promoting a leak or two.



The parasitic drain is 0,4mA only. So it will take more than 1 year to completely drain the batteries...


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## nickanto (Jul 8, 2009)

I just ordered a TK40 and 8 Enloops, do I have to worry about this combination at all? Do I need to unscrew anything while I store the light? I'm new to these high dollar lights. I've got a couple of rechargeable Streamlights, but that's about it. This will be my first high dollar LED light.


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## flasherByNight (Jul 8, 2009)

Well since noone else has said it yet....

 I'll send you 8 duracells coppertops in exchange! (I'll throw in 2 extra with free shipping) :naughty:


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## Illum (Jul 8, 2009)

nickanto said:


> I just ordered a TK40 and 8 Enloops, do I have to worry about this combination at all? Do I need to unscrew anything while I store the light? I'm new to these high dollar lights. I've got a couple of rechargeable Streamlights, but that's about it. This will be my first high dollar LED light.



watch for cell polarity!

Since the TK40 is dealing with 8 cells in 4s2p [or a pair of 4 cells in series] configuration an incorrectly loaded battery would result in an imbalance of voltage potential between the two strings. The string with the cells loaded correctly will reverse charge the string with one or more battery thats loaded incorrectly and may cause an explosion. This will occur regardless of whether the cell holder is inserted into the light or whether or not the light is on.

A recent incident of this occurred with lithium LiFeS2 Energizer "L91" cells


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## HKJ (Jul 8, 2009)

nickanto said:


> Do I need to unscrew anything while I store the light?



This depends on how much you use the light, it will drain the batteries in about a year. I.e. if you recharge the batteries every 6 month, you do not need to unscrew anything. But if you wish to store the light for longer, it is a very good idea to unscrew or even take the batteries out.


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## kramer5150 (Jul 8, 2009)

cujet said:


> At the show last weekend the Fenix dealer told me that the 40 draws power all the time. So, according to him, you must unscrew the tailcap a bit, when storing the light.
> 
> So, if true, the original post may have been correct, the light could be at fault by draining the batteries fully, thereby promoting a leak or two.



Curious...have studies been done to conclude that low level parasidic type drain (in and of itself) increases the odds of Alkaline leaks in electronic devices? Obviously draining a cell past its capacity will increase those odds... but what about slow drains within the cells capacity?

Not trying to be confrontational or defensive of Fenix.... they _HAD _to know what they were getting into with an 8x cell count.


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## nickanto (Jul 8, 2009)

HKJ said:


> This depends on how much you use the light, it will drain the batteries in about a year. I.e. if you recharge the batteries every 6 month, you do not need to unscrew anything. But if you wish to store the light for longer, it is a very good idea to unscrew or even take the batteries out.




Cool, I'll be using it weekly and probably charging every 2-4 weeks, so I guess I won't have any issues????


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## waddup (Jul 8, 2009)

nickanto said:


> Cool, I'll be using it weekly and probably charging every 2-4 weeks, so I guess I won't have any issues????


unless you run it empty every time you use it


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## jirik_cz (Jul 8, 2009)

kramer5150 said:


> Curious...have studies been done to conclude that low level parasidic type drain (in and of itself) increases the odds of Alkaline leaks in electronic devices? Obviously draining a cell past its capacity will increase those odds... but what about slow drains within the cells capacity?



Alkaline cells are mainly used in clocks, remotes and many other applications with a constant small drain... They should be designed for this kind of usage


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## Illum (Jul 8, 2009)

jirik_cz said:


> Alkaline cells are mainly used in clocks, remotes and many other applications with a constant small drain... They should be designed for this kind of usage



carbon zinc was initially designed for Überlow drains over a long distance time...hence very little of them leaked sitting in clocks or thermometers. But very often do they leak in flashlights. 

alkalines are good for loads up to 200ma and preferrably pulsed loads, like a remote control or a fire alarm. 

Anything higher I'd consider NiMH, LiCoO2, LiFeS2, etc


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## MrGman (Jul 8, 2009)

Although its been mentioned briefly as unbalanced or unmatched cells, this really needs to be brought out more. This is really a bad thing to have 8 cells in series and run them down. The chances that all 8 are matched in their output capacity is much lower than just having 2 or 3. The chances that after some initial high drain followed by steady state low drain the first cell to discharge then starts to reverse charge by 7 other cells still making forward voltage rather than all 8 cells maintaining forward voltage is too high. Its too much of a risk to expect 8 cells in series to discharge and not have one go to a reverse voltage condition before they are all substantially discharged. This is more of a risk for damaging this particular device than 400uA of steady state draw of its own. 

I don't know if any one has bothered to run tests on Alkalines to show how much disparity there is in them since you can't recharge them after a full life load test but I am sure they can't all have the same capacity. Some will drop voltage sooner than others under the same load current. 

We don't know from the OP if all the cells were new and fresh together, from the same package of eight. They could have all been "new" but from 4 different packages of 2 or 2 different packages of 4 for instance, and they could have been different lot/date code units, where one package was older than the other and even that would make a difference.

So even though I would simply blame Alkaline batteries in general I would say some fault has to go to a design that puts 8 batteries in series to help set up this type of condition in the first place. I might do this with 8 Nicads or 8 NiMH, I wouldn't do this with 8 alkalines and I know I would not put 8 Lithium whatevers in series in any device either. 

Although this flashlight has a robust mechanical design, Its electrical design in that it can take 8 Alkaline batteries and put them in series is a weakness, since it obviously can allow this type of situation to happen and this is a first failure. We will never know for sure if it was simply battery leakage or 1 or 2 cells started to reverse charge and therefore rupture because of that, but the likelyhood of the latter goes up with the multiplication of battery number.

A wall clock with 1 AA or 1 C cell battery or other applications that use only 1 Alkaline battery rarely ever fail and that should tell you something right there. G.


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## kwkarth (Jul 8, 2009)

MrGman said:


> Although its been mentioned briefly as unbalanced or unmatched cells, this really needs to be brought out more. This is really a bad thing to have 8 cells in series and run them down. The chances that all 8 are matched in their output capacity is much lower than just having 2 or 3. The chances that after some initial high drain followed by steady state low drain the first cell to discharge then starts to reverse charge by 7 other cells still making forward voltage rather than all 8 cells maintaining forward voltage is too high. Its too much of a risk to expect 8 cells in series to discharge and not have one go to a reverse voltage condition before they are all substantially discharged. This is more of a risk for damaging this particular device than 400uA of steady state draw of its own.
> 
> I don't know if any one has bothered to run tests on Alkalines to show how much disparity there is in them since you can't recharge them after a full life load test but I am sure they can't all have the same capacity. Some will drop voltage sooner than others under the same load current.
> 
> ...



All 8 cells are not in series with one another.

they are wired in 2 groups of 4, so you actually have 2 groups of 4 cells in series...2 banks of 6v in parallel with one another. Not quite as bad as 8 in series


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## AusKipper (Jul 8, 2009)

kwkarth said:


> One can never underestimate the proclivity of the buying public to;
> 
> 
> Ignore any written or spoken instructions.
> ...



Lol, I dont think I have EVER read the instructions for ANYTHING before trying to figure it out myself first. MAYBE if I get stuck on something I will go look at the instructions...


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## Illum (Jul 8, 2009)

AusKipper said:


> Lol, I dont think I have EVER read the instructions for ANYTHING before trying to figure it out myself first. MAYBE if I get stuck on something I will go look at the instructions...



in that case don't jeer the company or believe certain aspects of the warranty is still in service towards your advantage:candle:

lol... series imbalance is alright as voltages per cell often runs with a measure of deviancy whether it be batch differences or temperature in storage. Stuffing them in pairs will effectively balance the strings as long as the voltage differential is no greater than a percentage of the voltage from one cell. 0.2V difference is a heck of alot better than 1.2V difference:wave:

Perhaps no one here is ready for a 10xAA driven HID just yet...


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## MrGman (Jul 8, 2009)

kwkarth said:


> All 8 cells are not in series with one another.
> 
> they are wired in 2 groups of 4, so you actually have 2 groups of 4 cells in series...2 banks of 6v in parallel with one another. Not quite as bad as 8 in series


 

That is good to know, I stand corrected. That does make it a level better but still not impervious to having a reverse charging cell or 2.


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## MorePower (Jul 8, 2009)

MrGman said:


> I don't know if any one has bothered to run tests on Alkalines to show how much disparity there is in them since you can't recharge them after a full life load test but I am sure they can't all have the same capacity. Some will drop voltage sooner than others under the same load current.



AA alkaline cells from the same batch *should be* within 1% of each other with regard to capacity.

However, it's hard to *guarantee* that when manufacturing them at a rate of tens of thousands per hour.


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## recDNA (Jul 9, 2009)

AusKipper said:


> Lol, I dont think I have EVER read the instructions for ANYTHING before trying to figure it out myself first. MAYBE if I get stuck on something I will go look at the instructions...


 
In your defense...if a product has a reasonably high probability of bursting into flame because you insert a battery backwards I think it is the responsibility of the manufacturer to post a warning in every ad. The advertising dept. may not like it but the cost of ensuing litigation will be far greater than losses in sales.

I mean if a even ladder has a warning label not to fall off...


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## Marduke (Jul 9, 2009)

If someone improperly uses a device causing an incident, they fully deserve the Darwin Award they just earned for it.


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## Egsise (Jul 9, 2009)

recDNA said:


> I mean if a even ladder has a warning label not to fall off...


God bless US and A. :huh:


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## kwkarth (Jul 9, 2009)

It never ceases to amaze.... People today just don't want to accept the consequences of their actions. How did we breed such a society?
:thinking:


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## John_Galt (Jul 9, 2009)

I'd like to think it was the whole, every child is special and excellent, "heres youre gold star for breathing today, sonny" type of in breeding. Also, I was painting a house on top of a 16' ladder today, and I didn't read any of the warning labels. But I'm still here... 
Weird


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## kwkarth (Jul 9, 2009)

John_Galt said:


> I'd like to think it was the whole, every child is special and excellent, "heres youre gold star for breathing today, sonny" type of in breeding. Also, I was painting a house on top of a 16' ladder today, and I didn't read any of the warning labels. But I'm still here...
> Weird



Glad you're still here, and I bet if you'd fallen off the ladder, you wouldn't have tried to sue the ladder manufacturer.


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## AusKipper (Jul 9, 2009)

recDNA said:


> In your defense...if a product has a reasonably high probability of bursting into flame because you insert a battery backwards I think it is the responsibility of the manufacturer to post a warning in every ad. The advertising dept. may not like it but the cost of ensuing litigation will be far greater than losses in sales.
> 
> I mean if a even ladder has a warning label not to fall off...



Thats ok, i dont really need a defence. I have never busted anything by not reading the manual, most things are pretty common sence, particuly something as simple as a torch... insert battery, turn on.

I mean, if the thing was going to detonate a small nuclear device if I did insert a battery in back-to front then I would expect a warning in big letters... but otherwise I dont think its neccessary.

The only time I look at a manual for a torch was for my TK40, but that was because I couldnt figure out how to make it change modes... not because I couldnt put in the batteries


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## AusKipper (Jul 9, 2009)

kwkarth said:


> It never ceases to amaze.... People today just don't wan't to accept the consequences of their actions. How did we breed such a society?
> :thinking:



Well, first America has a fairly large and intrusive government compared to what it had originally, telling people exactly what they can and cant do for public safety. So as a result, "some" people assume that, so long as they are not breaking any laws... nothing could not possibly go wrong.. IE sure its pouring rain, the road is slippery, and the inside of my windscreen is dirty, but the speed limit is 100 (kmh) so I can do that safely.. and if i crash i'll jump up and down and blame the gov for setting the speed limit too high.

USA isnt so bad at this, but the UK is a complete nanny state...

Second problem, more in the USA than other countries, is all the ridiculous litigation people get away with, like suing people for cutting yourself on the broken glass when your robbing a house... etc etc.


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## ColoradoStoneman (Jul 9, 2009)

TangoFoxtrot said:


> The Fenix is too lightly built in my opinion. I was disappointed the moment I picked it up. My Surefire lights are made of thicker metal and have a positive solid feel of quality when I click the switch. The Fenix feels cheap. I had also ordered a PD30 and it feels cheap too. I don't think it will last years like my Surefire already has. Even a $20 2-cell Maglite looks and feels more solid and better made than the flemsy TK40. I won't be buying anything made by Fenix again based on build quailty, even if the Duracell batteries were at fault.


 
First of all, I have a couple Surefires. My 6PD with the LF HO-09 and 2 IMR 16340's is a nice little incan torch. It is well made, as everyone knows.

As for Fenix, they are great lights. I have an PD20, PD30, LD01, and a TK11. My wife has a LD10 and a TK20 (eneloop only - no alkalines).

I can't find any fault with any of them, other then not using a LOP reflector on the TK11. The Cree donut is pretty bad on that one, so I find that I prefer the Jet-III M over the TK-11. I see no reason why my Fenix lights would not give good long term service just like a Surefire.

As for the TK40, I don't think the idea of using 8 AA's was a good one. For that class light, I have a Jet M1X. Two 18650's and you are set. Carrying a couple 18650 spares, and charging is much easier then 8 AA cells.

Build quality aside, Surefire has some catch up with LED lights. The LX2 Lumamax looks like a fine light. But $200? It has one fixed low setting, and won't take an 18650? If it's any brighter then my Jet-III M, I would be suprised. On top of that, the Jet-III has an 18650 in it, and I can set low to any level I want. All for $85, and it has a quality build.

Beyond that, I don't know what "feels flimsy" means. Not to start a war, but making blanket statements on how inferior Fenix lights are, will get a rebuttle.

Nothing wrong with spending some extra money for a Surefire if you want, but there are other lights that are plenty rugged, and don't require a second mortgage.


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## tebore (Jul 9, 2009)

Good old USA. 

That's why we have instructions on peanut packets.


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## AusKipper (Jul 10, 2009)

tebore said:


> That's why we have instructions on peanut packets.



Getting way off topic now, but you gotta laugh when packets of peanuts have written on them in fine print "may contain traces of peanuts or other nuts"

I would hope my pack of peanuts would contain more than traces of them...


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## marc123 (Jul 10, 2009)

Just got my TK40. I have had a few torches over my years which I have used for my work as a police officer. These incluse the standard issue Mags and then my own including Fenix, Nitecore, Surefire etc. I have to say I am very impressed with this light. I am running Eneloops and I think that is a must. I don't think there is any more issue with them than running one or two 18650's. Really, when you are dealing with 630 lumens either way you cannot expect a simple answer. If you want the lumens then you have to do the work. If this means making sure 8 Eneloops are charged evenly then so be it. If it means using 2 x 18650's with the precautions about charging etc then so be it. Don't expect this performance from idiot proof lights. I can't say anything bad about the light, it is amazing. The 18650's have just as many drawbacks and I don't think going with the AA's was a bad isea as long as you don't use alkalines. This is my opinion only, feel free to flame me if you like.


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## mikekoz (Jul 10, 2009)

marc123 said:


> Just got my TK40. I have had a few torches over my years which I have used for my work as a police officer. These incluse the standard issue Mags and then my own including Fenix, Nitecore, Surefire etc. I have to say I am very impressed with this light. I am running Eneloops and I think that is a must. I don't think there is any more issue with them than running one or two 18650's. Really, when you are dealing with 630 lumens either way you cannot expect a simple answer. If you want the lumens then you have to do the work. If this means making sure 8 Eneloops are charged evenly then so be it. If it means using 2 x 18650's with the precautions about charging etc then so be it. Don't expect this performance from idiot proof lights. I can't say anything bad about the light, it is amazing. The 18650's have just as many drawbacks and I don't think going with the AA's was a bad isea as long as you don't use alkalines. This is my opinion only, feel free to flame me if you like.


 

I will agree with you. At least when alkalines malfunction, they do not turn your light into a pipebomb and possibly cause a fire. :sick2:. But you are correct, all batteries can have problems. I think the TK40 is an amazing light, and it is also different. There are a million 18650 lights out there, but right now, this is the only AA megalight. I never had any thoughts of putting alkalines in mine, but that was mainly for cost reasons. The idea that they would leak, however, was in the back of my mind. Only use rechargeables in this light folks....it is safer and more cost effective, and you will bet much better performance from it!!:twothumbs


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## adrianmariano (Jul 10, 2009)

Illum said:


> carbon zinc was initially designed for Überlow drains over a long distance time...hence very little of them leaked sitting in clocks or thermometers. But very often do they leak in flashlights.
> 
> alkalines are good for loads up to 200ma and preferrably pulsed loads, like a remote control or a fire alarm.
> 
> Anything higher I'd consider NiMH, LiCoO2, LiFeS2, etc



Actually I had alkalines leak in my wall clock. I had them leak in my ($100) kitchen scale. (I was able to clean those up.) Alkalines killed two streamlights (one with plastic body). I sent those back to streamlight for repair...but if I'd realized I could hit the battery maker instead I would have tried that. I've had them leak in storage in the refrigerator. I lost an Underwater Kinetics light too, and I think at least two maglites. As soon as I learned about low self discharge NiMH I eliminated all alkalines from my house, at least as much as I could. I still have 9V batteries in the smoke alarms and I think my multimeter and an IR thermometer. Any good alternatives for these yet? And I have one light that uses AAAA cells, which I keep unloaded in a plastic bag with the light.


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## Illum (Jul 10, 2009)

:huh2:

I am grateful for not seen any of those incidents you have described...



> Good old USA.
> 
> That's why we have instructions on peanut packets.



yep, while being as simple as possible in its contents, I'm guessing its for easier reading and probably because I had them on an international airline
"open package, eat nuts"


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## lolzertank (Jul 10, 2009)

adrianmariano said:


> Actually I had alkalines leak in my wall clock. I had them leak in my ($100) kitchen scale. (I was able to clean those up.) Alkalines killed two streamlights (one with plastic body). I sent those back to streamlight for repair...but if I'd realized I could hit the battery maker instead I would have tried that. I've had them leak in storage in the refrigerator. I lost an Underwater Kinetics light too, and I think at least two maglites. As soon as I learned about low self discharge NiMH I eliminated all alkalines from my house, at least as much as I could. I still have 9V batteries in the smoke alarms and I think my multimeter and an IR thermometer. Any good alternatives for these yet? And I have one light that uses AAAA cells, which I keep unloaded in a plastic bag with the light.



For 9V batteries, there's NiMH rechargeables, though I don't think they're LSD. There's also the Ultralife lithium primaries. I think there's also 9V Li ion batteries too. I've never heard of an AAAA rechargable. Oh, and in case you didn't know, you can get AAAA cells from some alkaline 9V batteries.


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## adrianmariano (Jul 10, 2009)

lolzertank said:


> For 9V batteries, there's NiMH rechargeables, though I don't think they're LSD. There's also the Ultralife lithium primaries. I think there's also 9V Li ion batteries too. I've never heard of an AAAA rechargable. Oh, and in case you didn't know, you can get AAAA cells from some alkaline 9V batteries.



Took a quick look. The NiMH rechargeables seem to have pathetic capacity, like 200-300 mAh. Doesn't seem suitable for smoke alarms and rarely used multimeters, etc. The Ultralife lithium primaries have 1200 mAh for comparison. I saw that Thomas Distributing was selling one low self discharge battery made by Tysonic (??). I might consider switching to the ultralife ones, though. 

I had heard about the AAAA inside 9 V, but the light is a streamlight stylus that I hardly ever need, so I haven't been going through the batteries. It's good to know, though, because the AAAA are impossible to find and insanely expensive.


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## bansuri (Jul 19, 2009)

Well, if there's one thing this site is good for it's convincing me to spend more money. That's not a BAD thing considering the cost of 8 eneloops are 1/3 the cost of the lights they'll be powering.






I have NiMH in most, but not all of my lights. Correction, I NOW have NiMH in all lights except the old 2xD LED Mag. Gonna load that up with some eneloops in d-cell adapters. It's just a kitchen cabinet light now. 
I've been good about keeping NiMH AAA's in my fancy Logitech remote but they do their slow death thing so I'm grabbing some eneloops for that also.
Thanks all for sharing your tales of woe, it's not like I don't have my own, but it's so easy to get complacent regarding batteries. You'll have a "dry" spell and everything's cool, then BAM a device goes from being awesome to just another corroded piece of junk.
Plastic, metal, alkalines do not discriminate. 
Also, the TK40 looks awesome, I read the torture test and put that light in my unofficial queue, but that's a hell of a lot of batteries. Is the idea of a couple/few big fat D-cell NiMH 10,000mAh batteries wrong? 8 points of failure seems high to me, although being able to run on 4 if/when a cell fails is a bonus.

Thanks again for all of your contributions and opinions.


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## IMSabbel (Jul 19, 2009)

bansuri said:


> Well, if there's one thing this site is good for it's convincing me to spend more money. That's not a BAD thing considering the cost of 8 eneloops are 1/3 the cost of the lights they'll be powering.



I just took a look, 8 eneloops are less than 20€ on amazon. 
I am sure other places will have them still lower.

How much is a tk40 again?


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## John_Galt (Jul 19, 2009)

kwkarth said:


> Glad you're still here, and I bet if you'd fallen off the ladder, you wouldn't have tried to sue the ladder manufacturer.



Well, actually, since writing this, I have fallen off of that ladder. It's one of those (it's not actually a little giant, as they sell on tv, but it's the same thing) little giant type ladders. Well, anyway, I had it folded up like a big "W", so I could scrape the underside of the eaves of this house I'm painting. I was sitting on the middle section, leaning back, and I stepped forward to reach further down the side of the house, but I stepped on one of the unsupported outer sections. Needless to say, I went tipping forward, big arc thru the air, landed on my hands and knees.:laughing: But it was all my fault (see, all is not lost in America, their is still one teenager who understands that actions have consequences, and am able to deal with them), so I'm not suing. Besides, with my luck, the company that manufactured the ladder would be out of business, due to the economy, and lawsuits...

Here's what I tell all of my friends... "If you're going to be stupid, you gotta be tough..."


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## thedeske (Jul 19, 2009)

Even with long experience, I still purchased more alkaline love until this year. I wonder how many frozen, melted openings I needed to 'Get The Point'

Never underestimate the power of Brand Recognition and it's advertising. The 3 sustained & 4 short notes in the adds probably crossed my ears 1000 plus times.


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## bansuri (Jul 19, 2009)

IMSabbel said:


> How much is a tk40 again?



It's about $150 - $160, maybe cheaper from china sites but I'm cautious buying "better" lights from them based on a single bad experience trying to do just that on my first Fenix. Since then I've been buying from 4Sevens and EliteLED and couldn't be happier.
Anyway, my 1/3 fraction was based on a set of 8 eneloops compared to any of my flashlights in the $60 range, LD10, D10, LF3XT. Sorry I wasn't clear in my original post.

For _me_ it no longer makes any sense keeping an alkaline in a flashlight of that, or really _ANY_ value. The quality of the above mentioned lights and even my cheaper DX lights is high enough that I don't think the day will ever come that they won't be useful to some degree so I'm not gonna sabotage them with alkalines.

It looks like the TK40 is a hit and has proven there is a market for a Fenix large form factor- high output light but this thread has, at least for now, convinced me to wait and see what follows up this model.


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## nickanto (Jul 19, 2009)

Can someone reccomend a good charger for my Eneloops? Right now I have a charger that came with some Energizer NIMH batteries that I bought for a digital camera. Would that charger be alright or do I need a better one if I want to get the full performance out of my batteries?


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## jahxman (Jul 19, 2009)

nickanto said:


> Can someone reccomend a good charger for my Eneloops? Right now I have a charger that came with some Energizer NIMH batteries that I bought for a digital camera. Would that charger be alright or do I need a better one if I want to get the full performance out of my batteries?


 
I have a LaCrosse BC-700 which is very good at keeping NiMH batteries conditioned and healthy.


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## zgundam (Jul 19, 2009)

nickanto said:


> Can someone reccomend a good charger for my Eneloops? Right now I have a charger that came with some Energizer NIMH batteries that I bought for a digital camera. Would that charger be alright or do I need a better one if I want to get the full performance out of my batteries?



If you want a quality NiMH charger go for the Maha C9000... picked one up along with 8 Maha 2700mah rechargeables for my TK40 and I'm mighty impressed with the build-quality / usefulness of it :twothumbs

The only reason why I picked up a TK40 was to prepare for the inevitable Zombie Apocalypse. Ability to use Alkalines for such a high lumen output torch is a plus since it might be hard to find power to recharge rechargeables....


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## thedeske (Jul 19, 2009)

zgundam said:


> Ability to use Alkalines for such a high lumen output torch is a plus since it might be hard to find power to recharge rechargeables....



Or you can get the DC cable for your car.


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## mavwong (Aug 13, 2009)

Well, said. This is exactly what I have been thinking when I read the TS problem. 

In case your explanation is not layman enough, I'll try my best again here.

Primaries cells voltage are not guarentee to be exact, and when you put 2 sets of 4-in-series and parreller them, the slightly higher voltage set will "charge" the other slightly lower sets. And because they are Primaries, these reverse charge can't bring up the voltage of the lower set. Instead, it may damage it and cause voltage drop even more and create larger voltage diffrence.

This situation will made worst if just one of the cell is a lemon or having lower voltage out put. Imaging it's L91 litium, if one gone bad before you knew it, sound like a time boom to me.

Before anyone panic. Solution is simple. When you use Alk or Litium prim cell (that is, non rechargable), put in only 4 cell. (if you are bad luck, you still might get cell leak, that's the part and pacel of prim cell)

Want more capacity, get eneloop.






MrGman said:


> Although its been mentioned briefly as unbalanced or unmatched cells, this really needs to be brought out more. This is really a bad thing to have 8 cells in series and run them down. The chances that all 8 are matched in their output capacity is much lower than just having 2 or 3. The chances that after some initial high drain followed by steady state low drain the first cell to discharge then starts to reverse charge by 7 other cells still making forward voltage rather than all 8 cells maintaining forward voltage is too high. Its too much of a risk to expect 8 cells in series to discharge and not have one go to a reverse voltage condition before they are all substantially discharged. This is more of a risk for damaging this particular device than 400uA of steady state draw of its own.
> 
> I don't know if any one has bothered to run tests on Alkalines to show how much disparity there is in them since you can't recharge them after a full life load test but I am sure they can't all have the same capacity. Some will drop voltage sooner than others under the same load current.
> 
> ...


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## dwminer (Aug 15, 2009)

mavwong said:


> Well, said. This is exactly what I have been thinking when I read the TS problem.
> 
> In case your explanation is not layman enough, I'll try my best again here.
> 
> ...


 

*Finally someone understands what's going on. Thanks for the explanation.*
*Dave*


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## Locoboy5150 (Jan 5, 2010)

TangoFoxtrot said:


> The Fenix is too lightly built in my opinion. I was disappointed the moment I picked it up. My Surefire lights are made of thicker metal and have a positive solid feel of quality when I click the switch. The Fenix feels cheap.



Yeah, go by subjective feel and not actual tests:

https://www.candlepowerforums.com/threads/233856

Darn that crummy TK40 build quality! Pure garbage! :laughing:

Give me that kind of crummy product quality any day.

Oh well, what can you do? :shrug:


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## berry580 (Jan 5, 2010)

TangoFoxtrot said:


> 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?
> 
> ...


Clearly you're not sure what you're talking about.
It's the batteries that leaked right? Not the flashlight.

Try using NiMH AAs in the TK-40 and chances are you'd be exponentially happier with this light. Using alkaline batteries on high drainage devices (e.g. TK-40) is not the best choice.


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## Geban (Jan 8, 2010)

NeonLights said:


> This (and the user interface) is one of the things holding me back from buying a Fenix TK40, the battery issue. Lithiums are too expensive to feed the thing, and buying and maintaining 8 matched NiMH batts is more than I want to mess with, and feeding it 8 alkalines is too risky, in case I leave it somewhere for any length of time.


If you had a Ferrari, would you run it on anyting but premium fuel and not service it at a Ferrari authorized garage? 
I wouldn´t.

I guess it´s the same with flashlights, if you buy an expensive flashlight you probably want to run it on the best batterys possible.
IMO If you can´t afford expensive batterys, don´t get that expensive flashlight.


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## LittleBill (Jan 8, 2010)

Geban said:


> If you had a Ferrari, would you run it on anyting but premium fuel and not service it at a Ferrari authorized garage?
> I wouldn´t.
> 
> I guess it´s the same with flashlights, if you buy an expensive flashlight you probably want to run it on the best batterys possible.
> IMO If you can´t afford expensive batterys, don´t get that expensive flashlight.




not only that but at 8 batterys per use, why in the world would you use alkalines? man i love running my flashlights. its one of the reasons i got away from cr123(did not know of rc123 at the time) because everytime i turned on the light i was thinking how much it cost me.

yea the initial cost is a bit much, but now i don't care how long it runs, that makes it priceless

i have no idea how anyone can blame a flashlight for a battery leakage. thats just insane


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## Moonshadow (Jan 8, 2010)

> i have no idea how anyone can blame a flashlight for a battery leakage. thats just insane


Try reading post 114 again. It's the unusual design of the light, with two banks of 4 cells in parallel, that appears to be creating the conditions that make the batteries more prone to leakage.


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## Hacken (Jan 8, 2010)

FlashlightsNgear.com said:


> *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.



my mag 3AA LED flashlight had corrosions inside of it too because of Alkaline batteries. just like FlashlightsNgear.com said.. there is a reason why i don't buy or use AA flashlights anymore.


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## Outdoors Fanatic (Jan 8, 2010)

Geban said:


> If you had a Ferrari, would you run it on anyting but premium fuel and not service it at a Ferrari authorized garage?
> I wouldn´t.
> 
> I guess it´s the same with flashlights, if you buy an expensive flashlight you probably want to run it on the best batterys possible.
> IMO If you can´t afford expensive batterys, don´t get that expensive flashlight.


 
I completely disagree! 

TK40s perhaps biggest selling point, is the fact that it is the first high-end high-powered Quad-Die flashlight which could be powered by cheap, easy to find, piece of crap alkalines. 
So with that said, imagine if Ferrari said: "The new Ferrari Napoli is the 1st V-12 engine Ferrari compatible with multi-fuel types--including cheap unfiltered lead gas". And a customer had his car ruined because he used lead gas, would you blame him or the manufacturer?
:thinking:

It is a design flaw, don't try to sugar coat it. Either a product is compatible with a given power source or it isn't, period.


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## LeifUK (Jan 8, 2010)

Outdoors Fanatic said:


> I completely disagree!
> 
> TK40s perhaps biggest selling point, is the fact that it is the first high-end high-powered Quad-Die flashlight which could be powered by cheap, easy to find, piece of crap alkalines.
> So with that said, imagine if Ferrari said: "The new Ferrari Napoli is the 1st V-12 engine Ferrari compatible with multi-fuel types--including cheap unfiltered lead gas". And a customer had his car ruined because he used lead gas, would you blame him or the manufacturer?
> ...



It is compatible. This is true of any consumer product that uses AA cells inline. It is true of the Mini Maglite, for example. That is why the instructions say to remove the cells if you do not use the product for an extended period of time. 

Decent quality NiMH cells and a decent charger do not cost much. Using the UK as a guide (I come from UK-land), 8 decent LSD NiMH cells + 1 decent charger = £25 online, 8 decent alkaline cells ~ £5. So it won't take long for NiMH to work out much cheaper. (I use ~4 cells per week in my 2*AA torch.) And NiMH gives better performance. What's more, I bet you use AA cells in other products. I use them in my GPS receiver, and my Nikon flash. So that charger is used for cells in other products too! And if you area bunny hugger, you must be on cloud nine as NiMH means less waste, less toxins in the environment, less materials mined, less land despoiled.


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## Ragiska (Jan 8, 2010)

Outdoors Fanatic said:


> I completely disagree!
> 
> TK40s perhaps biggest selling point, is the fact that it is the first high-end high-powered Quad-Die flashlight which could be powered by cheap, easy to find, piece of crap alkalines.
> So with that said, imagine if Ferrari said: "The new Ferrari Napoli is the 1st V-12 engine Ferrari compatible with multi-fuel types--including cheap unfiltered lead gas". And a customer had his car ruined because he used lead gas, would you blame him or the manufacturer?
> ...



so, do you use foreign generic, substandard, explosion prone cr123 cells in your cr123 lights? if you were to do so and one exploded from being mismatched out of the package in a 2-cell light, it would be the light's fault and not the crap cells? because a light should be able to use ANY cell for the designated power source no matter how crappy it is, correct? seriously, use some common sense. i know you are anti-AA everything, but WOW!!


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## Geban (Jan 8, 2010)

Outdoors Fanatic said:


> I completely disagree!
> 
> TK40s perhaps biggest selling point, is the fact that it is the first high-end high-powered Quad-Die flashlight which could be powered by cheap, easy to find, piece of crap alkalines.
> So with that said, imagine if Ferrari said: "The new Ferrari Napoli is the 1st V-12 engine Ferrari compatible with multi-fuel types--including cheap unfiltered lead gas". And a customer had his car ruined because he used lead gas, would you blame him or the manufacturer?
> ...


Yes, it´s true that in case of "emergency" it will run on crap alcalines, an also it´s true that any, and I stress ANY Ferrari can run on cheap fuel in case of emergency. (Guess that´s a design flaw to?)

But with both the flashligt and the Ferrari I wouldn´t go flat out with cheap fuel or batteries.
That´s just dumb. :shakehead


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## se4g4e (Jan 8, 2010)

Hacken said:


> my mag 3AA LED flashlight had corrosions inside of it too because of Alkaline batteries. just like FlashlightsNgear.com said.. there is a reason why i don't buy or use AA flashlights anymore.


Absolutely, it's the flashlight's fault those alkaline batteries leaked <insert facepalm here>.


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## thedeske (Jan 8, 2010)

se4g4e said:


> Absolutely, it's the flashlight's fault those alkaline batteries leaked <insert facepalm here>.



darn copper top propaganda gets me every time - it took 2 frozen mags and a melting remote for things to sink in


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## Ozgeardo (Jan 9, 2010)

Just to put in my 2 cent worth, I have had issues with "counterfeit" Duracells. They were excellent visually identical batts bought from a supposedly repudiable smaller trader at retail price.  
They were so good a copy that I sent them back to the manufacturer believing that they were genuine. (reasonably good customer service too may I note in helping me and providing details plus supplying some genuine batts at no charge)
I seldom use primary Alkaline nowadays but I have never had any more "leakages" since using Duracells purchased from a Major Retail Chain store who I believe would not make bulk purchase from other than genuine suppliers.

Taking on board what has been said about the battery configuration of 8 cells contributing to the problem, this may well be an issue but I have never had this issue when using genuine quality cells.


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## Swedpat (Jan 9, 2010)

Just a question: is it risk for alkalines to leak long time before last date?


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## Geban (Jan 10, 2010)

Swedpat said:


> Just a question: is it risk for alkalines to leak long time before last date?


Jupp, det finns risk för det. 

Yes, if you don´t store them properly they might leak.
Personaly I keep my alkalines in the fridge.


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## mfm (Jan 10, 2010)

Geban said:


> Jupp, det finns risk för det.
> 
> Yes, if you don´t store them properly they might leak.
> Personaly I keep my alkalines in the fridge.



"Refridgerated storage is neither necessary nor recommended".

In any case, they may leak no matter what you do.


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