# Protected vs unprotected 18650 batteries ?



## Scarface26 (May 4, 2014)

I'm new to LED flashlights and this forum, but have recently purchased a Fenix PD35 (GREAT, by the way) and have been reading up on batteries. Why would someone choose to purchase an unprotected 18650 battery for use in their flashlights? It seems that a battery with a protection circuit would be a much better choice.


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## gravelmonkey (May 4, 2014)

Scarface26 said:


> I'm new to LED flashlights and this forum, but have recently purchased a Fenix PD35 (GREAT, by the way) and have been reading up on batteries. Why would someone choose to purchase an unprotected 18650 battery for use in their flashlights? It seems that a battery with a protection circuit would be a much better choice.



Unprotected is cheaper and more 'reliable' in the sense that there's less to go wrong. They're also smaller in size so more likely to fit.

Personally, I prefer protected cells; I've harvested a few laptop battery packs but use the cells as backup-backups.

Edit: I should clarify that the above is regarding LiCo Cells. For IMR and LiFePO4 cells, they're considered 'safe chemistry' so a protection circuit isn't needed.


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## tripplec (May 4, 2014)

Scarface26 said:


> I'm new to LED flashlights and this forum, but have recently purchased a Fenix PD35 (GREAT, by the way) and have been reading up on batteries. Why would someone choose to purchase an unprotected 18650 battery for use in their flashlights? It seems that a battery with a protection circuit would be a much better choice.


No reason not to go protected. Verify the length and buy proven cells. Why someone wouldn't is NOT because of price. There aren't expensive. Those people must think they can get away with it until all goes wrong. Much like with an without a condom, you have to know when to quit.


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## mcnair55 (May 4, 2014)

For single cell use i have no issues using an unprotected cell but for more than one cell i would only use protected, and only ever buy protected for either for ease of use.


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## thedoc007 (May 4, 2014)

Since your question was general, I'll take a stab at it. There are some lights that REQUIRE an unprotected cell to function properly. For my TK75vn, for example, which was current boosted, my standard protected cells would not maintain turbo mode. After just a few seconds, it would step down. So obviously I had a good reason to go unprotected in that case.

It is a fact that protected cells definitely are more expensive...maybe not by a lot, but to some people it makes a difference. 

Theoretically the protection circuit always draws a little power from the battery, even when you aren't using it. This can lead to faster self-discharge. And it does reduce efficiency slightly...any time you make a circuit more complex (i.e., adding a protection circuit) it is absolutely inevitable that you will lose some efficiency. However, modern high-quality cells have VERY low self-discharge with or without the circuit.

Another reason is the size...the protection circuit usually adds at least 2-3 mm to the length of the cell. And in some cases, it adds almost 5 mm. This does lead to issues in the real world...some lights have tight tolerances, and adding just that little extra length can mean the cell doesn't fit at all. 

Another reason is that the protection circuit can fail. Unprotected cells are just a simpler design.

In summary, I personally would recommend protected cells if they will work for your specific uses. Never a bad idea to have an extra safety feature. But unprotected cells clearly do show some advantages. Which one is better depends on the individual user.


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## RetroTechie (May 4, 2014)

Personally I've always had a preference for things that aren't more complicated than they absolutely, necessary must be. And like thedoc007 said, a protection circuit introduces another _potential_ point of failure. That said, Li-ions are not as foolproof as NiMH's or alkalines. And the chances of a protection circuit failing should be pretty slim compared to the chances of other stuff around a battery failing. So there's good reasons to use protected cells.

For single-cell lights and _if you know what you're doing_, unprotected cells are okay. If not (and for multi-cell lights, specifically: series configuration), better use protected cells. At least until you have a bit more experience using Li-ions. And have read a few of the horror stories...  :devil:

18650 Li-ion batteries pack a lot of punch, and deserve some respect. Choose & treat them with care, and you'll be fine.


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## StorminMatt (May 5, 2014)

Also keep in mind that many lights have built-in overdischarge protection. And typically, this built-in protection is actually more conservative than the protection in protected batteries (ie it cuts power at a higher voltage). This eliminates ALOT of the need for protected batteries.


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## vicv (May 5, 2014)

Personally I rarely use protected cells but mostly my cells are all Imr. That way I can use smaller cells to power powerful lights. Like an 18350 for a 4A draw xm-l or 2x 18350 to power a p91. I really don't care about the fact that lico cells have higher capacity as I charge my cells very often. Usually they're at 3.8-3.9v when they go on the charger. Get a good charger and take responsibility for your cells and the protection circuit is unnecessary


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## Tobias Bossert (May 9, 2014)

There is another benefit of protection board build in a cell:
It makes the cell short circuit resistant!
If you use a battery connected to the device via a cable you should use protected cells to avoid hasard in case of cable failure *under all circumstances*.
In any case you should avoid to have a short circuit with unprotected cells - it could be dangerous even if the short circuit lasts only for a short time.


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## vicv (May 9, 2014)

Very good point. I'll admit it here and I'll probably be ridden for it but was a stupid mistake. I use Imr cells for vaping as well as flashlights. So I carry extra 18500s with me. I always put them in a case in my lunch bag. Well one morning after not enough sleep I just grabbed a couple extra cells and put them in my pocket which really is fine. Unfortunately later I threw a bunch of change in that pocket:fail: so I'm walking around and all of a sudden my pocket is about a million degrees. Quickly emptied my pocket on the floor and half the coins and the one battery were too hot to hold. And I've years of experience with these and know better but screw ups happen. Protected cells would've avoided that. But they can't provide 6a regular use either


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## HKJ (May 9, 2014)

vicv said:


> Protected cells would've avoided that. But they can't provide 6a regular use either



Some protection does first trip at currents above 10A.

6A for short bursts is fairly easy to find, you do not need the protection much above 6A to handle that. For batteries that can continuous deliver 6A you need batteries with a trip current above 7A. 

You can find the trip currents in my battery tests.


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## vicv (May 9, 2014)

Ya there's cells that can handle it but not 18500 I think. And even then they wouldn't provide the voltage I'd need. Imr cells are just better for vaping application. Just don't put loose li ion cells in your pocket full of change!


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## InspectHerGadget (May 14, 2014)

StorminMatt said:


> Also keep in mind that many lights have built-in overdischarge protection. And typically, this built-in protection is actually more conservative than the protection in protected batteries (ie it cuts power at a higher voltage). This eliminates ALOT of the need for protected batteries.



It sounds like the protected cells would be better then as it offers safety and potentially more useable capacity.

Unless I misunderstood, it sounds like an point in favour of protected cells.

Aside from size, for stock torches, I don't see any advantage to using unprotected cells unless you simply enjoy rolling the dice. Maybe there is a price advantage?


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## thedoc007 (May 14, 2014)

InspectHerGadget said:


> Aside from size, for stock torches, I don't see any advantage to using unprotected cells unless you simply enjoy rolling the dice. Maybe there is a price advantage?



If you read the other posts in this thread, you'll see that several advantages of unprotected cells have already been covered. And yes, they are cheaper.


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## psychbeat (May 14, 2014)

Idk - the protection adds a safety feature in some ways and a hazard in others. 
If you've ever had a protected cells thin little "positive strip" short on you you'll know what I mean. 
Mine burned thru the wrapper & smoked like crazy. 

The other thing is instant cut off. 
My p60 led modules have low voltage warning with a flicker every few seconds which is preferable to complete cutoff when riding a bike on steep mountain trails in pitch black 

I'm not saying protected are worse in all cases but they're definitely not safer in all cases either. 
It's a trade off like most things. 
I personally have only been buying raw cells like the new panny PFs.


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## funkychateau (May 14, 2014)

thedoc007 said:


> Since your question was general, I'll take a stab at it. There are some lights that REQUIRE an unprotected cell to function properly. For my TK75vn, for example, which was current boosted, my standard protected cells would not maintain turbo mode. After just a few seconds, it would step down. So obviously I had a good reason to go unprotected in that case.
> 
> It is a fact that protected cells definitely are more expensive...maybe not by a lot, but to some people it makes a difference.
> 
> ...



Besides the protected-cell issues you mentioned, another is that a semiconductor device is in series with the battery. While the "on" resistance of the protection circuit is low, it does increase the amount of voltage sag under a particular current draw. Some applications are more sensitive to this than others. For example, a buck-only driver will fall out of regulation sooner, or a driver with low-voltage shutdown may detect sooner.

My personal opinion is that protected Li-ion cells are needed for lights that use two or more in series. They are also needed for single-cell lights which incorporate boost circuitry. For single-cell lights having buck-only or linear regulation, or direct drive, I can generally detect visible dimming before the cell is completely drained. So I'm OK with unprotected cells in that application, even if the light has no built-in voltage monitor.


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## psychbeat (May 14, 2014)

Even on direct drive lights it's pretty darn obvious when the cells get low. 
If u run em down to 2.5v yer gonna see it even with a low VF emitter. 
It would suck to have a dd light switch on in yer bag with an unprotected cell but it seems unlikely that it would explode unless something happens when u try to bring it back to life by charging. 
Not really worth it if cells are ~10$ or less shipped.


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## STORMINORMAN (May 14, 2014)

OK, let me get this straight... It is safe to use two, stacked, protected Li-Ion 17500 3.7v batteries in place of 3X 123a primary batteries in a 3G Surefire (with a P60L 6-9v led dropin) or, for example, a Solarforce L2M with an 18650 extender and a 3.0-9v led drop-in? I know it would be OK to use two red AW IMR batteries, what I'm concerned about is the common warning on protected cells that the protection circuits are "designed for single cell operation" vs. "pack building": but is using two protected cells stacked an example of "pack building", or am I misinterpreting the nature of the warning?


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## vicv (May 14, 2014)

Battery packs have their own protection circuit for the whole battery. The single cells don't need it and would only complicate the build. For stacking batteries in a light either use protected cells or safe chemistry cells and use only matched cells. Protection circuits are no excuse to not look after your cells


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## STORMINORMAN (May 14, 2014)

vicv said:


> Battery packs have their own protection circuit for the whole battery. The single cells don't need it and would only complicate the build. For stacking batteries in a light either use protected cells or safe chemistry cells and use only matched cells. Protection circuits are no excuse to not look after your cells



So... 1st of all: THANKS to vicv! for the almost immediate response.

Based upon your post it appears I was misinterpreting the standard manufacturer's warnings about protected cells: one _*can *_safely use, for example 2 X 17500 protected cells instead of 3 X 123a primary cells with an appropriate drop-in? One *can* safely use 2 X 18650 protected cells with (at least) a 9v led drop-in? 

I'm in no way disregarding the comment about "...no excuse to not look after your cells" either. Have upgraded my charger with this specifically in mind and am looking to buy some more modestly-priced cells for multiple-cell use (as in "TWO stacked") but don't want to forego protection in that my lights don't have the built-in protection circuits like some do.


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## vicv (May 14, 2014)

No problem. Rereading my post it seemed a bit offensive if that's the case I apologize was not my intention. Was meaning it as a general statement and not implying you didn't look after your cells. That being said if buying protected cells gives you peace of mind then by all means they are the best for you. I personally just use Imr cells and I don't care about runtime or capacity as I really never discharge my cells beyond 3.7V so they're always at 40+% when they go back on the charger. I use my cells for incans and vaping mostly so voltage is important to me. And yes any circuit designed for 3 lithium primary cells can be used with 2x li ion


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## RetroTechie (May 15, 2014)

STORMINORMAN said:


> what I'm concerned about is the common warning on protected cells that the protection circuits are "designed for single cell operation" vs. "pack building": but is using two protected cells stacked an example of "pack building", or am I misinterpreting the nature of the warning?


2 Individual cells in series is just that, nothing more... Protected cells are wise in that case.

What makes a battery pack is 'glueing' those cells together _permanently _like in a laptop or powertool battery. For such use, an X number of 'naked' (unprotected) cells are paired with a battery monitoring / protection circuit designed for _that_ exact configuration.

So kind of the same purpose, but different ways to do it depending on application.


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## StorminMatt (Jun 27, 2014)

InspectHerGadget said:


> It sounds like the protected cells would be better then as it offers safety and potentially more useable capacity.
> 
> Unless I misunderstood, it sounds like an point in favour of protected cells.
> 
> Aside from size, for stock torches, I don't see any advantage to using unprotected cells unless you simply enjoy rolling the dice. Maybe there is a price advantage?



A protected cell wouldn't give you a runtime advantage. For instance, many lights will cut out at 3.0V. And the protection circuit on the battery may cut out at 2.7V. Even though the protection circuit may cut out lower, the light will still cut out first. No capacity gained.

With everything said here, the advantages of unprotected batteries are:

1. Unprotected batteries are shorter and generally thinner, allowing better fitment in many applications.

2. Unprotected batteries have one less failure point. Sometimes, even dropping a protected battery can damage the protection circuitry.

3. The protection circuit introduces additional resistance, which can increase voltage drop.

4. The protection circuit introduces some drain, which effectively increases aelf discharge, eapecially if the battery has sat for long periods.

5. As the other poster pointed out, although protected batteries are safer in many instances, there are leads running alongside the can with just a thin insulating layer between the lead and can. This can create a direct short should the insulation be damaged (say, by dropping hard against a rough surface or contact with sharp objects).

6. Cost is usually a little higher for protected cells.

In the end, everyone must go with what they are most comfortable with. However, suffice it to say that there are MANY instances where protected cells really aren't necessary.


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## HKJ (Jun 27, 2014)

StorminMatt said:


> 4. The protection circuit introduces some drain, which effectively increases aelf discharge, eapecially if the battery has sat for long periods.



That drain is not significant.

There is also the detail that LiIon manufacturers requires protection when using their batteries.


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## StorminMatt (Jun 27, 2014)

HKJ said:


> There is also the detail that LiIon manufacturers requires protection when using their batteries.



But what does this mean? MUST a battery use an actual protection circuit? Or would built-in protection on a light suffice? And in the end, what are they going to do if someone uses the cell unprotected? Send the Li-Ion police to your house late at night and lock you up for not using a protection circuit on your battery?


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## StorminMatt (Jun 27, 2014)

Delete


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## SilverFox (Jun 28, 2014)

Hello StorminMatt,

It has to do with "Good Manufacturing Practices."

A device manufacturer approaches a battery manufacturer wanting to use their cells. They won't provide the cells until they have reviewed and approved of the protection circuit utilized. The battery manufacturer doesn't want the liability of an injured person coming after them if the battery pack fails in the device.

In hobby use there are no "deep pockets" and the responsibility of proper use lies with the person using the device. The battery manufacture is held harmless because the hobby user never had their protection device approved by the manufacture and the manufacture never sold the batteries for hobby use.

Tom


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## leaftye (Jun 28, 2014)

I recommend protected, but all ~200 of my 18650's are unprotected.


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## richardcpf (Jun 29, 2014)

*What I recommend for flashlight starters or the average user:* Protected cells, and a reliable, easy to user charger. I use Xtar SP2.

*What I actually do:* unprotected cells for all flashlights that only I use. I measure voltage, capacity and wear of each battery once every couple months and pair them to be used in specific lights. Charge done with a iCharger 106B+ and 4-6S diy cradle.


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## elbowroom (Apr 20, 2015)

Funny.........



tripplec said:


> No reason not to go protected. Verify the length and buy proven cells. Why someone wouldn't is NOT because of price. There aren't expensive. Those people must think they can get away with it until all goes wrong. Much like with an without a condom, you have to know when to quit.


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## magellan (Apr 20, 2015)

vicv said:


> Very good point. I'll admit it here and I'll probably be ridden for it but was a stupid mistake. I use Imr cells for vaping as well as flashlights. So I carry extra 18500s with me. I always put them in a case in my lunch bag. Well one morning after not enough sleep I just grabbed a couple extra cells and put them in my pocket which really is fine. Unfortunately later I threw a bunch of change in that pocket:fail: so I'm walking around and all of a sudden my pocket is about a million degrees. Quickly emptied my pocket on the floor and half the coins and the one battery were too hot to hold. And I've years of experience with these and know better but screw ups happen. Protected cells would've avoided that. But they can't provide 6a regular use either



Have had that happen twice but with NiMH batteries. I don't usually put lithium ion batteries in my pocket because they have a lot more energy, so have never had it happen with one of them. Also, I've spent so much money on different battery holders at this point that, even if I did put one in my pocket, it would probably be in a plastic or Delrin holder where it would be safe.


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## magellan (Apr 20, 2015)

StorminMatt said:


> A protected cell wouldn't give you a runtime advantage. For instance, many lights will cut out at 3.0V. And the protection circuit on the battery may cut out at 2.7V. Even though the protection circuit may cut out lower, the light will still cut out first. No capacity gained.
> 
> With everything said here, the advantages of unprotected batteries are:
> 
> ...



Great information, thanks. I've copied that into my battery notes.


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## magellan (Apr 20, 2015)

Scarface26 said:


> I'm new to LED flashlights and this forum, but have recently purchased a Fenix PD35 (GREAT, by the way) and have been reading up on batteries. Why would someone choose to purchase an unprotected 18650 battery for use in their flashlights? It seems that a battery with a protection circuit would be a much better choice.



I prefer protected lithium cobalt batteries and don't have many unprotected large batteries in that chemistry, i.e., 18650s or bigger. Most of the unprotected lithium cobalt batteries I have were sent to me with flashlight purchases here on the CPF. 

I also have a number of unprotected lithium manganese and lithium iron phosphate batteries which I don't worry about as much because their safer chemistry is less likely to go into thermal runaway. As has been discussed here, some applications require a high drain, unprotected cell. I only have one or two lights like that, but this is very common in the vaping community, especially people running so called custom sub-ohm hotwire mech mods. I'm not a vaper myself but I follow developments there a bit because of the battery issues.

Where I get into potential trouble is I have a lot of small flashlights that use CR2 3.0V or 14250 3.7V size batteries or smaller, such as 10180, 10220, or 10280, and these batteries are all unprotected lithium cobalt types. For some reason protected cells in these small sizes just aren't made, so I have no choice but to use unprotected cells.


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## elbowroom (Apr 21, 2015)

Hello! I'm trying to figure out if the Fenix HP12 headlamp will run on both protected and unprotected 18650's. Thanks


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## NoNotAgain (Apr 21, 2015)

elbowroom said:


> Hello! I'm trying to figure out if the Fenix HP12 headlamp will run on both protected and unprotected 18650's. Thanks



I'm going to go out onto a limb and say that since Fenix only sells protected cells, that that's what you should be using. Having said that, IF you monitor battery voltage and don't allow it to drop below 3.2 volts or so, and recharge it when required, there should be no problems in using an unprotected cell.

If you just want to use the light and recharge the battery when it stops working, then a protected cell is best for you.


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## PD-35 Noob (Jan 3, 2016)

I see a big difference in cost. 

The Panasonic 3400mAh (NCR18650B) unprotected cells cost a little more than $5 each and the protected ones go for $20 each (based on ZL634 price)

I haven't seen any cheap good brand 3400mAh 18650 for nearly the same prices protected and unprotected. I'm new so I may just not have looked enough.

I've used my Fenix PD-35 with unprotected batteries for a year now (light usage) with no problems. I also left one in my glovebox in all the summer months in the Florida heat. (hopefully my car didn't burn up).

My only concern is possible water damage from underwater activities at sea. I'm a little afraid of them exploding if they get shorted by the seawater (if it manages to get in my light). 
I'll also be getting a ZL 18650 light and planning to use the same type of battery.

I still haven't exploded nor do I have cells that do not work. Can someone point to disasters caused by unprotected 18650s in single cell flashlights?


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## ChrisGarrett (Jan 4, 2016)

I fly naked, but I check my cells with a DMM often.

If you mind doing that and protected cells fit your light, then go that route.

Chris


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## bella-headlight (Jan 4, 2016)

I also go commando (no protection) but my lights are all either single cell or parallel cells.
The cells themselves are good quality & I use a good charger
None of my lights are massive drain & I check with a DMM before & after each usage & charge.
I am happy enough doing things this way.


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## light-wolff (Jan 4, 2016)

PD-35 Noob said:


> I'm a little afraid of them exploding if they get shorted by the seawater (if it manages to get in my light).


Seawater won't short a battery. It is not that conductive.
Corrosion and PCB malfunction caused by seawater is a different thing.


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## duvallite (Jan 8, 2016)

For those that are using unprotected IMR batteries in single cell lights that don't have a low-voltage indicator or protection circuit, I have a couple of questions.

1. How often do you recommend to check the voltage on the battery, especially in lights that don't get used on a steady basis and may sit unused for very long periods of time? 
2. At what voltage would you recommend would be a good time to throw them on the charger, as a safe general practice?

I'm using 18650, 16340, and 14500 IMR batteries in the lights I have, and want to be as safe as I can with my new hobby.


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## Telkwa (Jan 9, 2016)

It'd be great to have a sticky that specified which lights should run prot. and which should not. 

A few days ago someone posted indicating only dummies run protected cells in a Zebralight. Yet it doesn't take much lurking to run into other people saying that Flashlight X _should_ have protected cells.

You can see why a newb would get confused. I'm pretty sure that the "protected or not" issue hinges on the fact that some lights have minimal protective internal circuitry, while others have every safeguard known to man, but I don't understand all the twists and turns.

A few weeks ago I didn't have any 18650 lights. Now I'm the proud owner of a ZL H600w II, Armytek Wizard, and Nitecore HC30, and I honestly don't know which batteries should go where.


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## andrewnewman (Jan 9, 2016)

I fear that there are some more nuances to this. Flashlights with "built in protection" need to *at least* have a minimum voltage when they stop drawing power from the battery to protect the cell. Others might have a step down function or go into a low-power "limp home" mode. As long as they *eventually* stop drawing power before damaging the cell they might qualify as "smart". Any flashlight, however, that uses either a linear driver or a buck-driver that eventually drops into direct drive will demonstrate a dimming that would be hard for anyone not to notice. When the voltage supplied to the LED drops below the minimum Vf, the LED will stop illuminating. A CREE XPG, for instance gets dim at around 3.00 volts. It's very very dim at 2.75 volts. It will extinguish around 2.50 volts. If you are paying even a little attention, you can catch the dimming well before doing any damage. I, for instance, have no problem running a single 18650 in my Malkoff MD2 unprotected. I would never lend this to someone who might run the light all the way down, however. The big problem comes from lights with boost circuits that try to provide regulated power above the cell voltage. These can destroy a cell with no visual warning.


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## gyzmo2002 (Jan 9, 2016)

andrewnewman said:


> The big problem comes from lights with boost circuits that try to provide regulated power above the cell voltage. These can destroy a cell with no visual warning.


 
Good advice. I was planning to use my Armytek Predator pro v3 HI and Barracuda Pro v2 HI with unprotected cells. These lights have full regulated (boost) circuit and I will do some test with my multimeter to see how they handle the cells at low voltage. I don't want to go under 3.0v. They have a low voltage (10%) indicator (2 blinks) I think but I want to know at what voltage they start blinking. 

The Barracuda can be use with 1 or 2 cells. I know that 2 unprotected cells in series need more attention. I will use my multimeter and take many measures to do it. I have bought Evva 3500mah protected cells for the Barracuda but they are too thick. They don't fit in any of these 2 lights. I will use LG mj1 and hg2 to do the test.


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## Ace12 (Jan 24, 2016)

Would unprotected be better in a ZL H600fd III ?


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## ChrisGarrett (Jan 26, 2016)

Ace12 said:


> Would unprotected be better in a ZL H600fd III ?



If the H600xx Mk III is like the SC600 Mk III, you will have to run a naked cell, whether you want to, or not. 65mm +/- .5mm, IIRC. No button tops, either. Strictly a bare cell.

LG MJ1, Samsung 30Q, or Sanyo/Panasonic NRC18650GA, would be three to consider.

Chris


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## snowlover91 (Jan 28, 2016)

andrewnewman said:


> I fear that there are some more nuances to this. Flashlights with "built in protection" need to *at least* have a minimum voltage when they stop drawing power from the battery to protect the cell. Others might have a step down function or go into a low-power "limp home" mode. As long as they *eventually* stop drawing power before damaging the cell they might qualify as "smart". Any flashlight, however, that uses either a linear driver or a buck-driver that eventually drops into direct drive will demonstrate a dimming that would be hard for anyone not to notice. When the voltage supplied to the LED drops below the minimum Vf, the LED will stop illuminating. A CREE XPG, for instance gets dim at around 3.00 volts. It's very very dim at 2.75 volts. It will extinguish around 2.50 volts. If you are paying even a little attention, you can catch the dimming well before doing any damage. I, for instance, have no problem running a single 18650 in my Malkoff MD2 unprotected. I would never lend this to someone who might run the light all the way down, however. *The big problem comes from lights with boost circuits that try to provide regulated power above the cell voltage. These can destroy a cell with no visual warning.*



Great info especially the last part. That's one good feature with Zebralight, their lights step down to a lower level when the battery is low and this is a great warning to charge that battery. If you don't it'll drop down again then finally cut off if you continue using it. I believe the threshold is 2.7v under load which equals out to around 3v resting.


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## LGT (Jan 29, 2016)

snowlover91 said:


> Great info especially the last part. That's one good feature with Zebralight, their lights step down to a lower level when the battery is low and this is a great warning to charge that battery. If you don't it'll drop down again then finally cut off if you continue using it. I believe the threshold is 2.7v under load which equals out to around 3v resting.


Agreed. There is an abundance of info on using unprotected cells in this thread and a few others.
I was a little worried about having to use them in my new ZL sc600w III because I've only used protected. But after reading up on using unprotected for the last hour, I eagerly await them reaching full charge so I can finally use my new light.


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## Devon (Jan 30, 2016)

We have been using protected 18650 's mostly and a few other sizes for about 5 years now and in 3s1p configuration as well as stand alone.

In all that we have only had the protection circuit on a cell trip once due to heavy loading and a temp low voltage situation.

We have now decided to use quality unprotected cells, ncr18650ga.


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## Tachead (Jan 30, 2016)

ChrisGarrett said:


> If the H600xx Mk III is like the SC600 Mk III, you will have to run a naked cell, whether you want to, or not. 65mm +/- .5mm, IIRC. No button tops, either. Strictly a bare cell.
> 
> LG MJ1, Samsung 30Q, or Sanyo/Panasonic NRC18650GA, would be three to consider.
> 
> Chris



It is not like the SC600 MKIII and will take up to 69mm cells with or without PTC. I use Thrunite 3400mah protected(NCR18650b) in mine and it works perfectly.


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## Ace12 (Jan 30, 2016)

I ordered a couple Eagletac 3500mah. Should be here Monday.


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## NevC (Jun 7, 2016)

I am looking at an AceBeam K70.
I have noted various opinions and horror stories on this forum. I still have some doubts re what batteries to use in the K70.
AceBeam specify K70 must use 4 x high drain unprotected 18650 cells, or protected 18650 cells which PCB including 3 MOSFET
1 will Xtar VC4 be ok to charge unprotected batteries?
2 where do you get the specified protected cells? I have not found this info on batteries for sale.
3 what battery would you suggest?

The reason for a K70 is the distance it will be used for which is open field to 500m to tree line.


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## ven (Jun 7, 2016)

NevC said:


> I am looking at an AceBeam K70.
> I have noted various opinions and horror stories on this forum. I still have some doubts re what batteries to use in the K70.
> AceBeam specify K70 must use 4 x high drain unprotected 18650 cells, or protected 18650 cells which PCB including 3 MOSFET
> 1 will Xtar VC4 be ok to charge unprotected batteries?
> ...




1- yes , any charger that supports the 18650 4.2v cell, will charge protected or unprotected, INR or IMR cells
2-Not sure where you are, if USA check places like goinggear, illumn supply and mtn electronics. 
3- If you want protected, then the sanyo/panasonic GA 10a 3500mah from mtn electonics


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## Gauss163 (Jun 7, 2016)

ven said:


> 1- yes , any charger that supports the 18650 4.2v cell, will charge protected or unprotected, INR or IMR cells



Except some chargers will reject protected cells whose protection has tripped (so the cell measures near 0V). But you can easily workaround that by briefly charging the cell with another cell to release the protection. Other chargers have functionality that automatically perfoms that function (sometimes called "0V activation").


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## NevC (Jun 8, 2016)

Ven, many thanks for information. I am in Australia.
I have looked at MTN but they do not show the battery you said available to international buyers, only US buyers.
I have not found an Oz dealer who has that battery either. They have 3400mah 3.7v here.

I will continue to look at more dealers

thanks again


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## MAD777 (Jun 8, 2016)

Look for Efest IMR18650 3000mAh purple or Samsung INR18650-30Q pink.


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## mdmothi (Jun 9, 2017)

Hi 
I'm Mohamed Mothi From Chennai, India. I'm New to the Forum. Getting a Few Flashlights from Thrunite UK. The 18650 Batteries are very expensive. I was thinking about disassembling Mi 10000mah Powerbank which has 3x3350 mah 18650 batteries in it and using it on Thrunite TN35? Is it Advisable? Planning to get a XTAR VC2 PLUS charger to charge the batteries.


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## SilverFox (Jun 9, 2017)

Hello Mohamed,

Welcome to CPF.

Are you sure the Mi 10000 mAh Powerbank has round cells in it? When I did some searching it appeared that it was using LiPo cells. They are flat and won't fit into a round flashlight.

Tom


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## mdmothi (Jun 10, 2017)

SilverFox said:


> Hello Mohamed,
> 
> Welcome to CPF.
> 
> ...



There are 2 versions in Mi Powerbank. One comes with 3x3350mah 18650 L-ion batteries and the pro Version Comes with 10000mah Lithium Polymer Battery. I have the one that comes with 3x18650 battery(Link Below). Is it advisable to use the cells from the powerbank? Planning to Purchase XTAR VC2 PLUS Master Charger to charge the batteries. 

http://www.mi.com/in/pb10000/


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## SilverFox (Jun 10, 2017)

Hello Mohamed,

At this point you will need to take the powerbank apart and see what you have. If you end up with round cells, you are good to go.

Tom


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## degarb (Jun 11, 2017)

Skimmed thread looking for new angles,but missed any.

My one cent: 1. Get a smart charger that shuts off at 4.19 volts. I did buy 3 two bay dumb chargers that I tested pushing current into a full cell/also will charge a tripped cell that isn't reset with a jump.
2. I wouldn't buy a light that can't fit protected. 3. I need functional lights with useful runtimes,else I would own lights but never use them, as I was in the incandescent days. Thus, I have no use for high modes that cook the driver chips and led, while requiring unsafe and insane current from a cell. 4. I roll my eyes at people who claim they check voltage after each charge and before- as they too are human, and thus, do not do this if they use cells everyday. Multimeter break, the 9 volts die. Assumptions are made. 5. It is analogous to seatbelts, airbags,backup parachutes. In real life, as in experiments, there is one way things can go right: yet, one million,or more, ways things can go wrong! 6. Smart chargers, protected cells, two multimeter and a home built single cell volt tester: I still charge inside cookie tins. I know I Will not always be there to pull my cell off charger at 4.2 volt. 6. Researching, I saw the protected cell explosions could be traced to off brand cells sold as protected,but in reality they weren't. Bogus cells and bogus protection is a problem. Probably, tests exist to verify brand and protection. Nothing worse than a false sense of security. 7. Still get a few multimeter. I made two single cell meters from a single holsee and a volt readout chip,which works over 4 volts.


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## mdmothi (Jun 14, 2017)

I Removed the batteries from the Powerbank. The 18650 Batteries were from LG(LG F1L 3350mah). I put one of them on My Thrunite TN12 Which Arrived today and it worked without any issues. Need to buy a Charger to charge them, Probably Xtar VC2 Plus or Thrunite MCC-4S. After using the TN12, I'm confused about my 2nd torch Light Between TN35 and TN42NW. I'm buying it mainly to photograph mammals at about 40-60 Yards. it would be great if someone could help me out.



SilverFox said:


> Hello Mohamed,
> 
> At this point you will need to take the powerbank apart and see what you have. If you end up with round cells, you are good to go.
> 
> Tom


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## hunter357mag (Jul 20, 2019)

magellan said:


> Great information, thanks. I've copied that into my battery notes.



Clear and concise info, thanks from a newbie :thumbsup:


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