# Batteries for Fenix TK 75



## SeamusORiley (Dec 1, 2012)

I am new to quality flashlights and have not used a battery other than AA. 

I just ordered the new Fenix TK 75 after having experienced the Fenix model that uses AA batteries. The new order does not come
with batteries, so I will need the "18650" batteries (4) and a charger. 

*Can someone recommend battery/charger combo that will work well with this? I fear damaging the flashlight. 

Also, for other electronics, I use Eneloops AA and the XXX AA's as well, and find them to be terrific. Will these power up a quality Flashlight that calls for 18650 batteries? Safe to use?

I am still researching answers here and have been, so if it is that I simply haven't found the right newbie thread, I apologize. 

Thank you for your time.


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## xed888 (Dec 1, 2012)

SeamusORiley said:


> I am new to quality flashlights and have not used a battery other than AA.
> 
> I just ordered the new Fenix TK 75 after having experienced the Fenix model that uses AA batteries. The new order does not come
> with batteries, so I will need the "18650" batteries (4) and a charger.
> ...



why dont you just buy the entire kit? Fenix has chargers and 18650s and they would be best for you. if i recall correctly,t hey arent expensive either


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## SeamusORiley (Dec 1, 2012)

There was no kit offered otherwise I would have... thanks.


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## xed888 (Dec 1, 2012)

Might help if you mentioned where you're located.


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## lwknight (Dec 1, 2012)

The 18650 batteries are unique and cannot replace any AA.
A flashlight that requires 18650s will only work with 18650s unless its stated that it will also use cr123s.


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## SeamusORiley (Dec 1, 2012)

xed888, I am in the US and ordered from LA Police Gear. It was the only online place I found that had not sold out the initial run. 

For the past few weeks, I have been reading the forum and learning. I have never used anything but a AA or AAA battery. 

lknight, is there a 4 battery (18650) and charger set that you recommend?

thank you.


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## SeamusORiley (Dec 1, 2012)

thanks...also, if there are some good resources for learning, I am glad to read up any good links. This is a huge forum, and I have been reading for weeks but still are sifting through things.


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## neutralwhite (Dec 1, 2012)

for my fenix PD32 im using Fenix's own 18650's and there charger.
18650 'ARB L2' and 'ARE C1' charger. 
works very well, and its all fenix. 
no issues. 

thanks.


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## lwknight (Dec 1, 2012)

You can get the Sysmax I4 intellicharger but charging 4 cells takes double charging 2 cells time.
If you have 12 hours to wait then go for it. Otherwise you might want 2 chargers of either 4 or 2 cell capacity.
I have the Ultrafire wf139 and the sysmax I4. If I'm in a hurry I charge 2 in each otherwise just put all 4 in the I4.
BTW: the I4 is about $25.00 U.S. and the wf139 is around $20.

There are lots of chargers out there. The Pila is also highly recommended but still to charge 4 cells quickly you need 2 chargers.


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## SeamusORiley (Dec 1, 2012)

Thanks to both for replying. I will see to find out if batteries/charger is being sold with the TK 75.


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## SeamusORiley (Dec 3, 2012)

update: I found a different online dealer that is selling the TK 75 with batteries and a charger together, and was able to cancel my original order. This is a major purchase for me and felt more comfortable buying where the batteries and charger were also Fenix. 
Being careful of reputations, do posters generally share experiences with online stores? thanks again for the help, and the patience.


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## cheaperrooter (Dec 4, 2012)

*FENIX TK75 question*

I am totally upset now. I had my hopes pinned on getting a couple of TK75's for myself. But being a survivalist, my ONLY criteria is disposable batteries, which I stock several hundred of. I naturally ASSUMED it would take 8 - 123a, as the other Fenix's I have (PD31,32 and E50).

Just read their manual and it says NO!!!! Will only work in the low light level with 8 123a's. I DON'T UNDERSTAND THIS. IT'S STUPID TO ME. I know 18650 (think thats right) have more energy, buit why does it shut down with 123a???? I use them for camping and hiking, I don't exactly have outlets in the woods to recharge my flashlight with!!!!

I am not well versed ebough to understand WHY they will not work? Please explain to it me, as I if I was as I am, dumb and stupid in this area. Thanks, Louie


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## SeamusORiley (Dec 4, 2012)

*Re: FENIX TK75 question*

kind of a bummer. The TK 41 really is a nice flashlight and the 860 lumen is strong power. I am blown away by the ads for the new TK 75 and am excited about 2600 lumen lasting for 2 hours. This would light up my entire backyard ice rink and allow for solid visibility all winter. (rural) 
With my regular batteries, I use the Eneloops and have everything in the house running by them (except a need for higher powered XX models) and I have back ups, charged to go, when anything goes down. (what a battery nerd!) I learned early in life that dads need batteries and once I learned that Eneloops do not lose their power in storage, or do not drain out so quickly, I fell in love with them. Before Eneloop, I have had terrible performance from rechargeable batteries and eventually gave up using them.


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## TEEJ (Dec 4, 2012)

*Re: FENIX TK75 question*



cheaperrooter said:


> I am totally upset now. I had my hopes pinned on getting a couple of TK75's for myself. But being a survivalist, my ONLY criteria is disposable batteries, which I stock several hundred of. I naturally ASSUMED it would take 8 - 123a, as the other Fenix's I have (PD31,32 and E50).
> 
> Just read their manual and it says NO!!!! Will only work in the low light level with 8 123a's. I DON'T UNDERSTAND THIS. IT'S STUPID TO ME. I know 18650 (think thats right) have more energy, buit why does it shut down with 123a???? I use them for camping and hiking, I don't exactly have outlets in the woods to recharge my flashlight with!!!!
> 
> I am not well versed ebough to understand WHY they will not work? Please explain to it me, as I if I was as I am, dumb and stupid in this area. Thanks, Louie





Its about the voltage, and the ability to support a high FLOW RATE. The little 123's can't handle the load.

Each cell, 18650, or rechargeable 123, is rated at 3.7 v. The disposable 123's are rated at 3 v...and have lower capacity for *high current* devices. (Powerful lights)

So, using 8 CR123's just won't supply enough POWER to make the light work at full power...the way 4 18650's could power it...so it goes into limp modes to give you at least a little light.

My answer to being in the boonies with no power lines and receptacles, etc...is a simple foldable solar charger. (Cottonpickers) - Kicks *** compared to other solar chargers. 



So, when you get a more powerful light, it takes more power to run it. Your old disposables are too weak for the job, and you'd need to step up your power game to compensate.

The folding charger can pack like a thin notebook, but opens to a decent size, and can come with outlets for cells, phones, laptops or smart phones, etc. I have two battery boxes on mine, so it has massive storage capacity with little weight (18650 powered boxes)

Several hundred 123's to carry around can be replaced by a few 18650s. 

If the light takes 4 18650's....lets say you got 3400 mah versions....that means that the 3400 mah of the 18650 is going to last over twice as long as the 1500 mah a decent CR123 might have, and in the case of THIS light, even if they HAD the juice to run it...TWO 1500 CR123's (In series) would last LESS THAN half as long as one 18650.

So if you ran the light on full power for say 2 hrs a night, you could have those cells ready to go the next night. You could carry 8 18650's...and rotate them to cover rainy/cloudy weather, albeit with dual battery boxes, I could charge those 4 cells w/o needing any sunlight anyway.


Even if the 123's COULD handle the load...you'd need ~20 of them a night for the same nightly run time....based on a 1500 mah per CR123 rating.

If you were out for a week....that's *140* 123's you packed with you. (How many hundreds of these wee critters DO you have stock piled?)

Even at $1 per CR123, that's ~ *$140 bucks *in cells for the week.

So, the 18650 simply makes more sense from a financial standpoint...and from a physics standpoint. The REASON the light is so bright is that it takes advantage of the chemistry offered by the 18650. If it could take a lesser source, it would not be ABLE to be as bright, etc.










In short...its easier to carry the gear to run the light on 18650's than a pile of feeble old fashioned throw away CR123's. Also, you can run out of disposable 123's, say if things go south and you have to extend your stay so to speak...but you won't run out of rechargeable power.

If you need to, bring a back up light running on all the 123's you want.



Its one reason I carry a Klarus XT11. I can load CR123's, RCR123's, and 18650 power sources...its adaptable.


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## TEEJ (Dec 4, 2012)

*Re: FENIX TK75 question*



SeamusORiley said:


> kind of a bummer. The TK 41 really is a nice flashlight and the 860 lumen is strong power. I am blown away by the ads for the new TK 75 and am excited about 2600 lumen lasting for 2 hours. This would light up my entire backyard ice rink and allow for solid visibility all winter. (rural)
> With my regular batteries, I use the Eneloops and have everything in the house running by them (except a need for higher powered XX models) and I have back ups, charged to go, when anything goes down. (what a battery nerd!) I learned early in life that dads need batteries and once I learned that Eneloops do not lose their power in storage, or do not drain out so quickly, I fell in love with them. Before Eneloop, I have had terrible performance from rechargeable batteries and eventually gave up using them.



LOL

I have a ton of enloops and rechargeable nimh C and D cells I use for stuff that would have taken alkalines, but have more power and reliability with nimh's. I just look now for things that take 18650's, etc, so I get MORE power than possible for the same sized light with mere nimhs.


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## cheaperrooter (Dec 5, 2012)

*Re: FENIX TK75 question*

"Its about the voltage, and the ability to support a high FLOW RATE. The little 123's can't handle the load."

Thanks for an in depth reply explaining it to me. Though I disagree with you over the 123a versus rechargable stuff in general, ie survival and such, you did give me some more info to chew on a while (solar). And your explanation was one I could UNDERSTAND for once....well done. Still, I wish they would have just given the option for regular batteries of any type. In general, I just do not like any product, flashlights or not, not can ONLY RUN ON RECHARGABLES. From a susvival standpoint, that's just not good business :thumbsdow


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## TEEJ (Dec 5, 2012)

*Re: FENIX TK75 question*



cheaperrooter said:


> "Its about the voltage, and the ability to support a high FLOW RATE. The little 123's can't handle the load."
> 
> Thanks for an in depth reply explaining it to me. Though I disagree with you over the 123a versus rechargable stuff in general, ie survival and such, you did give me some more info to chew on a while (solar). And your explanation was one I could UNDERSTAND for once....well done. Still, I wish they would have just given the option for regular batteries of any type. In general, I just do not like any product, flashlights or not, not can ONLY RUN ON RECHARGABLES. From a susvival standpoint, that's just not good business :thumbsdow



If you think a little longer about it, disposables are not a good business, as, being a survivalist, you must have considered how LONG you might have to survive.

If you have to go even one month, you'd need close to 600 123's...and when they were gone...you'd have NOTHING but darkness.

What if you needed to survive for a YEAR? You will carry almost SEVEN THOUSAND disposable CR123's into the boonies with you? Really? 

If on foot, that's a LOT of extra luggage...and even if you have a truck, that's a lot of space/weight to lug around - Reducing mobility and increasing your profile, etc.



If you have to go a month with the 18650's and solar...well, it doesn't matter...you can. The 18650's have been lasting around 5-10 YEARS with normal care.

But, to the point in this thread at least...You could simply use a dimmer heavier light and carry hundreds of extra pounds of batteries for it....and forget that you COULD HAVE HAD a brighter, more compact light and ~ a pound of accessories...

..so that you can maintain your desired dependance upon non-renewable energy sources.




So, sure, if a light you like the performance/features of can take multiple energy sources, sure...options are great. But for survival (Despite much dogma to the contrary), renewable energy makes as much sense as hunting/gathering vs just bringing a lot of bottled water and canned goods, etc.

There's a place for both certainly...as it does give more adaptability...but renewables extend your time horizon where disposables have a finite horizon.

My personal view is that non-renewables are going to be useful when you are running for daylight and don't want to mess with anything but making distance between you and whatever is making you need to get away.

If you have a jar of pbutter you don't need to stop and kill dinner.

If needing to be away for a year....that's too much pbutter. Bring a few jars to get you by when needed, but start eating what's available when you can.


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## cheaperrooter (Dec 5, 2012)

*Re: FENIX TK75 question*

"What if you needed to survive for a YEAR? You will carry almost SEVEN THOUSAND disposable CR123's into the boonies with you? Really?"

Well, come on now, thats pushing the spectrum way tooooooo far to male a point. I am not running my light 24/7 in TURBO mode.....LOL. I have a PD31 that can do low light for 200 hours. In survivalist mode, low light is all you would use for the MOST part. So seeing as how there are roughly 12 hours of night per 24 hours, that gives me 1/2 month of usage, which equals 4 batteries per month or 48 batteries per year. Thats hardly thousands of batteries...(smiles humbly)


Plus, there are OTHER things I own which take 123a that DO NOT TAKE the 18650. As a survivalist, you try to get all your gadgets to run off of same battery if possible. Seeing as how I have about 300 123a's, I am good for a couple years. And al of them don't weigh that much. After that I will steal or come across someone elses 18650 (what's your address???LOL) 

Also, you are assuming that this solar (it may) will charge OTHER things as well, as I would hate to carry around a solar panel for that AND 15 other gadgets I own. Solar is ALWAYS an option for ANY survivalist, but again, just not my style, never has been. To each their own.

Question is where does it end? Solar charging fo this, for that, next thing you know I'm loaded up with solar gear for all my supplies... Me, myself and I, I'll just keep my 1000 or so stock of batteries in tact and go from there.


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## SeamusORiley (Dec 7, 2012)

*Re: FENIX TK75 question*



cheaperrooter said:


> I am totally upset now. I had my hopes pinned on getting a couple of TK75's for myself. But being a survivalist, my ONLY criteria is disposable batteries, which I stock several hundred of. I naturally ASSUMED it would take 8 - 123a, as the other Fenix's I have (PD31,32 and E50).
> 
> Just read their manual and it says NO!!!! Will only work in the low light level with 8 123a's. I DON'T UNDERSTAND THIS. IT'S STUPID TO ME. I know 18650 (think thats right) have more energy, buit why does it shut down with 123a???? I use them for camping and hiking, I don't exactly have outlets in the woods to recharge my flashlight with!!!!
> 
> I am not well versed ebough to understand WHY they will not work? Please explain to it me, as I if I was as I am, dumb and stupid in this area. Thanks, Louie



Did you decide on the TK75? 

It is some serious lighting, even if it means the battery must be rechargeable.


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## SeamusORiley (Dec 13, 2012)

*Re: FENIX TK75 question*

I received mine and it is something special. I bought a 2nd charger with a second set of batteries. Buying the Fenix charger and Fenix batteries was considerably more money, however. I thought it might be best as it is the recommendation from the flashlight's enclosed literature.


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## KILLER_K (Apr 17, 2013)

*Fenix TK75 battery suggestions*

Finally bought one of these Fenix TK75 led lights after reading up on them. Should make a good hunting light for me. Was wondering what the best batteries to get for this unit. Would also like to get a break down on the run time along with best mahs for this light. Unless there is a better light for the price. But it seems this is the best all around light for this price range. Hopefully I posted this in the right place.


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## kj2 (Apr 17, 2013)

*Re: Fenix TK75 battery suggestions*

I would go for the 3400mah Eagletac batteries.


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## KILLER_K (Apr 17, 2013)

*Re: Fenix TK75 battery suggestions*

Thanks for the suggestion. Looking at these on Amazon. They seem to be roughly around the $18.00 mark for each one. Going to do some price digging.



kj2 said:


> I would go for the 3400mah Eagletac batteries.


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## Lou Minescence (Apr 17, 2013)

*Fenix TK75 battery suggestions*

Fenix 2600 mah batteries are supposed to be good for high drain. HKJ has an 18650 battery review in the batteries section showing battery tests and applications. If you run the TK 75 on high a lot you might want to consider the Fenix battery. Either Eagletac or Fenix will be fine.


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## Rexlion (Apr 18, 2013)

*Re: Fenix TK75 battery suggestions*

I am reluctant to run multiple LiIon cells in a light. IMRs for me. I'll gladly trade some runtime for extra safety.


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## KILLER_K (Apr 18, 2013)

*Re: Fenix TK75 battery suggestions*

Could you please post the reasons why also? I was under the impression, the batteries and light would prevent this from happening. I like to have all the information in front of me while reading. I'm going to do a mini-review of this light. So all the information and help can be used on my end. Thanks



Rexlion said:


> I am reluctant to run multiple LiIon cells in a light. IMRs for me. I'll gladly trade some runtime for extra safety.


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## alpg88 (Apr 18, 2013)

*Re: Fenix TK75 battery suggestions*

panasonic are good cells, they even have hybrid imr, good for 10A, but capacity is low 2200mah


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## alpg88 (Apr 18, 2013)

*Re: Fenix TK75 battery suggestions*



KILLER_K said:


> Could you please post the reasons why also?



i'd like to hear that too, i use li ion in many multicell lights, as long as they are protected, good quality, you have nothing to fear, even trustfire never gave me any issue, i mostly use tenergy 2600, very good cells imo, not sure, however, how they perform at 3-4A draw, i don't pull more than 2A out of them


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## KILLER_K (Apr 19, 2013)

*Re: Fenix TK75 battery suggestions*

Also a good charger also. Need one of those as well. Might as well get a good charger along with some good batteries. Any suggestions on the charger? I would like one that will cover mostly everything, without breaking the bank.


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## Rexlion (Apr 19, 2013)

*Re: Fenix TK75 battery suggestions*

Protection circuits limit over-voltage charging and over-discharge. They do not protect against thermal runaway. A protected LiIon (by that I mean ICR, the most common type) can still vent with flames. 

You're talking about running multiple 18650s in series, right? What if one cell is not charged to the same level as the others? It may be user error, charger malfunction, or cell malfunction, the reason doesn't matter, but it can happen. If it does happen, you get energy from the higher-voltage cells suddenly flowing into (and trying to charge) the lower-voltage cell. Suddenly a ton of heat is generated. And maybe, POW.

IMR cells possess superior thermal stability. Also they are capable of safely handling much faster discharge rates. As I understand it, they are inherently safer chemistry, to the point where protection circuits are neither needed nor used.

I'm pretty sure I have read some folks' posts on this forum in the past about having their protected LiIon cells vent in a charger, scorching the surrounding area. Protection circuits can fail. But I can't recall ever hearing of an IMR doing this.


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## KILLER_K (Apr 21, 2013)

*Re: Fenix TK75 battery suggestions*

Thanks *Rexlion* for the post and information. I've narrowed it down to these 3 battery choices so far.
1) *Panasonic NCR18650B*
2) *Fenix ARB-L2 *
3) *EagleTac 3400mAh*

As far as a charger goes, not really sure. The Fenix charger or the Nitecore i4 was all I seen on Amazon.


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## kj2 (Apr 21, 2013)

*Re: Fenix TK75 battery suggestions*



KILLER_K said:


> Thanks *Rexlion* for the post and information. I've narrowed it down to these 3 battery choices so far.
> 1) *Panasonic NCR18650B*
> 2) *Fenix ARB-L2 *
> 3) *EagleTac 3400mAh*
> ...



Eagletac is using the Panasonic NCR18650B cell 
http://lygte-info.dk/review/batteries2012/EagleTac 18650 3400mAh (White-green) UK.html


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## herosemblem (Apr 21, 2013)

*Re: Fenix TK75 battery suggestions*



Rexlion said:


> I am reluctant to run multiple LiIon cells in a light. IMRs for me. I'll gladly trade some runtime for extra safety.



I was under the impression that IMRs were less safe than protected cells. I guess I have much learning to do...


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## alpg88 (Apr 21, 2013)

*Re: Fenix TK75 battery suggestions*



herosemblem said:


> I was under the impression that IMRs were less safe than protected cells. I guess I have much learning to do...



they are, if you short them (or it happens in a light for some reason) there is no pcb to brake the circuit, unlike protected cells, imr are capable of 10A normally and on sc can do more, they can heat things up quite a lot. they safety comes from the fact that they don't vent as lico do, that is true, however chances of exploding of good quality protected cells, are so small, that it really isn't a factor. how often have you heard laptops blow up due to batteries??? as long as they are protected, and you don't physically damage them, you'll be fine. just look at number of ppl using non imr protected cells on this forum alone.


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## herosemblem (Apr 22, 2013)

*Re: Fenix TK75 battery suggestions*

In my TK75, I use protected Samsung 3000 mah cells. 
You mentioned that IMRs dont vent like Lico cells. Well, what about li-ion cells? Or, is Lico and Li-ion the same thing?
I am wondering the safety advantages of IMR vs a protected Li-ion. Thanks!


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## alpg88 (Apr 22, 2013)

*Re: Fenix TK75 battery suggestions*

yes, li ion (none imr) = lico in this context . 

read smoke and fire section, you will have all the answers you are looking for, you'll see what happens in real world, not just on paper.

you use protected none irm cells, how is it working for you so far??? any smoke and fire????


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## herosemblem (Apr 22, 2013)

*Re: Fenix TK75 battery suggestions*

I currently use protected 18650, protected 14500 and protected rcr123. So far, no problems. 
Then again, I have not used these batteries to the point that they are so low that the light either dims or failsto turn on altogether. 

My assumption is that the protection circuits in quality protected li ion cells will discourage anything bad from happening, for example: allowing my tk75's protected 18650s to discharge to dangerously low levels. Id love to spend more hours reading at batteryuniversity, but hopefully someone can inform me here.

Of course people always advise us to use our DMM tool to measure the voltage, but I cannot get my harbor freight DMM to display a number Ivan understand, no matter which setting I flip the switch to.


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## Punchinello (Jul 22, 2013)

*Re: Fenix TK75 battery suggestions*



Lou Minescence said:


> Fenix 2600 mah batteries are supposed to be good for high drain. HKJ has an 18650 battery review in the batteries section showing battery tests and applications. If you run the TK 75 on high a lot you might want to consider the Fenix battery. Either Eagletac or Fenix will be fine.



When I asked the Fenix Store about the availability of 3400 MaH batteries, they replied: "We don't sell 3400 mah batteries since they don't effectively operate a Fenix flashlight. Fenix is designed for optimal performance with a 2800 mah battery. If you use a 3400 battery, the runtime is greatly shortened."

I would think that a greater capacity battery should run longer, but I'm no battery expert.

Can anyone enlighten me?


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## alpg88 (Jul 22, 2013)

*Re: Fenix TK75 battery suggestions*



Punchinello said:


> When I asked the Fenix Store about the availability of 3400 MaH batteries, they replied: "We don't sell 3400 mah batteries since they don't effectively operate a Fenix flashlight. Fenix is designed for optimal performance with a 2800 mah battery. If you use a 3400 battery, the runtime is greatly shortened."
> 
> I would think that a greater capacity battery should run longer, but I'm no battery expert.
> 
> Can anyone enlighten me?



lol, they want you to buy their cells. 

there is no way 3400 will have sorter runtime than 2800. 

this nonsence alone would be enough for me to never buy anything from those guys.


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## beamshots (Jul 23, 2013)

*Re: Fenix TK75 battery suggestions*

Nitecore NL188 3100mah (Panasonic cells Inside)at FASTTECH is 15$. http://www.fasttech.com/products/14...ore-nl188-37v-3100mah-18650-protected-recharg This is very good battery and price is ''cheap''.


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## walterwitt (Jul 24, 2013)

*Re: Fenix TK75 battery suggestions*



beamshots said:


> Nitecore NL188 3100mah (Panasonic cells Inside)at FASTTECH is 15$. http://www.fasttech.com/products/14...ore-nl188-37v-3100mah-18650-protected-recharg This is very good battery and price is ''cheap''.


Yeah... Or you could get 2 of the same cells with protection for cheaper if you don't mind it not saying nightcore on it http://www.fasttech.com/products/14...onic-ncr18650a-37v-3100mah-18650-rechargeable


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## walterwitt (Jul 24, 2013)

*Re: Fenix TK75 battery suggestions*



Rexlion said:


> Protection circuits limit over-voltage charging and over-discharge. They do not protect against thermal runaway. A protected LiIon (by that I mean ICR, the most common type) can still vent with flames.
> 
> You're talking about running multiple 18650s in series, right? What if one cell is not charged to the same level as the others? It may be user error, charger malfunction, or cell malfunction, the reason doesn't matter, but it can happen. If it does happen, you get energy from the higher-voltage cells suddenly flowing into (and trying to charge) the lower-voltage cell. Suddenly a ton of heat is generated. And maybe, POW.


I pretty sure it wouldn't work like that. All batteries can only be charged by current flowing through them backwards. Unless they were inserted the wrong way, the current in all the batteries would be flowing in the way that makes them drain. the only thing bat I see happening in this situation is the lower charged cell being over drained before the thing using it switched itself off. But even then, most protected batteries have a low voltage cutoff so it would stop the current before it drained too far. Even if they were in parallel which would cause a higher charged battery to charge a low one the protection circuit would trip if the current got to high.

Now you are correct that if there is a problem with the cell, or it's being over stressed, it can overheat and go boom.


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## Norm (Jul 24, 2013)

*Re: Fenix TK75 battery suggestions*



walterwitt said:


> Yeah... Or you could get 2 of the same cells with protection for cheaper if you don't mind it not saying nightcore on it http://www.fasttech.com/products/14...onic-ncr18650a-37v-3100mah-18650-rechargeable



Your comparing unprotected with protected, apples and oranges. One price is for two unprotected cells, the other is for one protected cell.

Norm


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## Punchinello (Jul 24, 2013)

*Re: Fenix TK75 battery suggestions*

Slightly off-topic, but I'd like to take advantage of the brain-power here. I plan on buying a Fenix TK-75, but I'm receiving conflicting advice on the best battery to use with it. 

Some say go for capacity and get 3400 mAh cells. But those who seem to know more about battery construction and chemistry say that 3100's and 3400's will not deliver the highest voltage for as long as a 2600 mAh cell; that there's a voltage vs. capacity trade-off, especially when running a TK75 at it's highest, most power hungry mode, rather than at medium or lower modes.

When I asked the Fenix Store about the availability of 3400 mAh batteries, they replied: "We don't sell 3400 mah batteries since they don't effectively operate a Fenix flashlight. Fenix is designed for optimal performance with a 2800 mah battery. If you use a 3400 battery, the runtime is greatly shortened."

Can anyone enlighten me?


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## HKJ (Jul 24, 2013)

*Re: Fenix TK75 battery suggestions*

It depends on the driver in the light.

In this chart I have included a 2600mAh and 3100mAh battery:







Anything above the yellow line will have constant brightness, below the yellow line brightness will vary with battery voltage.


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## Punchinello (Jul 25, 2013)

*Re: Fenix TK75 battery suggestions*

Thanks, HKJ. It doesn't look like I'd get significantly more out of a 3100 than a 2600, and with a 2600, I'd be able to use the highest brightness longer.


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## Punchinello (Jul 26, 2013)

*Re: Fenix TK75 battery suggestions*

I want to buy a TK75 and four Fenix ARBL2 2600 mAh batteries. Does anyone know a source that gives the best CPF or any other discount? I can't find any coupon codes on here. 

Many thanks.


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## AerialExplorer (Apr 21, 2016)

Hi there, 

Just bought TK75 2600 and now looking batteries for my flashlight, i have never used 18650 batteries, could you kindly 
recommend which batteries and charger will be better for my flashlight?

what do you think about this batteries and charger , will they work well with this?

XTAR VC4 
Protected Panasonic NCR18650B 3400mah Li-ion Battery PCB 

Thank you


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## NoNotAgain (Apr 21, 2016)

The Xtar charger is a good charger. 

The Panasonic 18650 B cell is also a good battery, but is being displaced by the Sanyo/Panasonic GA battery. The GA has more capacity which yields longer run times, but not much over the B. 

Where the GA shines is that they're rated for a higher amperage than the B battery. 

Being new to lithium batteries, it's not a bad thing to use protected batteries. 

Mountain Electronics sells a protected version of the GA battery for about the same price as the generic Panasonic B cell. 

The protected B is selling for $9.65 verses $9.95 for the GA.


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## MidnightDistortions (Apr 23, 2016)

cheaperrooter said:


> I am totally upset now. I had my hopes pinned on getting a couple of TK75's for myself. But being a survivalist, my ONLY criteria is disposable batteries, which I stock several hundred of. I naturally ASSUMED it would take 8 - 123a, as the other Fenix's I have (PD31,32 and E50).
> 
> Just read their manual and it says NO!!!! Will only work in the low light level with 8 123a's. I DON'T UNDERSTAND THIS. IT'S STUPID TO ME. I know 18650 (think thats right) have more energy, buit why does it shut down with 123a???? I use them for camping and hiking, I don't exactly have outlets in the woods to recharge my flashlight with!!!!
> 
> I am not well versed ebough to understand WHY they will not work? Please explain to it me, as I if I was as I am, dumb and stupid in this area. Thanks, Louie





SeamusORiley said:


> kind of a bummer. The TK 41 really is a nice flashlight and the 860 lumen is strong power. I am blown away by the ads for the new TK 75 and am excited about 2600 lumen lasting for 2 hours. This would light up my entire backyard ice rink and allow for solid visibility all winter. (rural)
> With my regular batteries, I use the Eneloops and have everything in the house running by them (except a need for higher powered XX models) and I have back ups, charged to go, when anything goes down. (what a battery nerd!) I learned early in life that dads need batteries and once I learned that Eneloops do not lose their power in storage, or do not drain out so quickly, I fell in love with them. Before Eneloop, I have had terrible performance from rechargeable batteries and eventually gave up using them.



You can also get the Nitecore EA81. Only provides half the lumens and takes 8 AA batteries. As for recharging batteries, it's easier to recharge with solar. The TK75 is definitely still good and i'd still buy one even though it only works best on li-ion. I still prefer to use Eneloops/NiMH for my flashlight needs but pretty soon i'm going to be able to play around with li-ion (safely of course) once i get all the AA/AAA flashlights i could ever want. There's a few C or D flashlights i want to get but again once all that is out of the way (including finding a new place) it'll be time to explore li-ion.


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## AerialExplorer (Apr 25, 2016)

NoNotAgain said:


> The Xtar charger is a good charger.
> 
> The Panasonic 18650 B cell is also a good battery, but is being displaced by the Sanyo/Panasonic GA battery. The GA has more capacity which yields longer run times, but not much over the B.
> 
> ...



Thank you for reply

Which one is better option from this two:

Panasonic NCR18650B 18650 3400mAh 3.7v Protected Button Top Batteries
http://www.ebay.com/itm/282015016933?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT


Sanyo NCR18650GA 3500 mAh Li-ion Rechargeable Button Top Protected Battery
http://www.ebay.com/itm/2x-Sanyo-NC...996626?hash=item3abd989512:g:v4QAAOSwzgRWws1G


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## NoNotAgain (Apr 26, 2016)

AerialExplorer said:


> Thank you for reply
> 
> Which one is better option from this two:
> 
> ...



Your Fenix TK75 doesn't require a button topped battery, so flats or button tops work.

Price wise, the 18650 "B" cell is cheaper and on a cost benefit analysis wins. That battery is going to be a tight fit in the battery carrier due to length. They fit, just they're tight.

The 18650 "GA" will run on higher power out puts longer due to being a 10 amp battery. I can't tell if that's the same protection circuit as used on the "B" batteries shown in the ebay listing. 

I've using the GA's in one of the Vinh modified TK75vnKT lights. I'm also using the extended run time kit which added 4 more cells to the mix. I don't use protected batteries. They (the unprotected battery) fit better in the carrier, and I check the voltage before charging, so I've got a good idea how long the light will run before charging.


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