# CR123 vs 18650?



## Obone (Dec 2, 2013)

New to these more powerful headlamps. I have been using CR123flashlights for years but just started using a Fenix PD35 and love it. I picked up some 18650's after reading about some CR123's having catastrophic failures. I'm now wanting to upgrade to a better headlamp and looking at the limited selection of 18650's. 

Should I be concerned about the risk of CR123's on my head?


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## TomasVarnik (Dec 3, 2013)

Well, if you are afraid to use CR123 on your head, you should also worry about the 18650, right? (If something goes wrong, it will be worse in a 18650)

There are many people who never wear lithium in headlamps, only Alkaline and NiMh...


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## Obone (Dec 3, 2013)

TomasVarnik said:


> Well, if you are afraid to use CR123 on your head, you should also worry about the 18650, right? (If something goes wrong, it will be worse in a 18650)
> 
> There are many people who never wear lithium in headlamps, only Alkaline and NiMh...



I know that I'm knew to this but I know that I had read in several parts of this forum where one of the problems with the CR123's was when two or more were used in series and there would be a difference in there charge state that led to the failure of one of the cells. I thought that this would not be a problem with the 18650's. 

Have I misunderstood the prior threads? If so please help me understand. I really enjoy the amount of light that I get from one of these and have not found any AAA or AA that come close.


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## skeeterbait (Dec 3, 2013)

Lithium, or any batteries for that matter, used in series where one battery has significantly different charge state, capacity, age, or internal resistance can cause one battery to exhaust before the other. This can result in the discharged battery receiving charge from the second battery in reverse. This can result in battery failure, leaks in alkaline, venting of hot toxic gas from lithium. Using a voltmeter, checking voltage of paired batteries, buying only quality fresh batteries, matching batteries of like age brand and capacity, use of batteries with protection circuits, all serve to minimize this risk. Also using lights that require only a single battery eliminates this risk. So of you are talking about switching from a two CR123 in series headlamp to a single 18650 lamp, then yes you are eliminating this risk.


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## Obone (Dec 4, 2013)

Thanks that was what I thought but I needed to have it verified by someone with more experience.


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## Littlelantern (Dec 6, 2013)

skeeterbait said:


> Lithium, or any batteries for that matter, used in series where one battery has significantly different charge state, capacity, age, or internal resistance can cause one battery to exhaust before the other. This can result in the discharged battery receiving charge from the second battery in reverse. This can result in battery failure, leaks in alkaline, venting of hot toxic gas from lithium. Using a voltmeter, checking voltage of paired batteries, buying only quality fresh batteries, matching batteries of like age brand and capacity, use of batteries with protection circuits, all serve to minimize this risk. Also using lights that require only a single battery eliminates this risk. So of you are talking about switching from a two CR123 in series headlamp to a single 18650 lamp, then yes you are eliminating this risk.


100% agreed with you.


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## Beacon of Light (Dec 25, 2013)

Was it CR123s or RCR123s that caused the explosions? I would assume primaries would be safe like how Alkaline would be safe.


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## inetdog (Dec 25, 2013)

Lithium primaries in series can still fail spectacularly if unmatched cells are used. They do not have under voltage and reverse charge protection.

Sent from my XT1080 using Tapatalk


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## TEEJ (Dec 25, 2013)

Beacon of Light said:


> Was it CR123s or RCR123s that caused the explosions? I would assume primaries would be safe like how Alkaline would be safe.




The opposite is actually the case. MOST of the mismatched internal resistance  is from primaries (cr123 for example) not from rechargables. When it is an rcr version, it tends to be a fake cell and/or w/o protection, or used w/o normal dmm checks.

This is MOSTLY due to the pretty common problem of unregulated lights that dim as the cells drain...and the scenario where the cells are partially discharged...but still might be good for spares, but, are removed to swap in freshies when heading out.

Eventually, there is a stash of partially discharged cells....and, no one typically sorted them by remaining mah, etc.

That eventually leads to using a partially discharged cell that is too different from its cellmate, and, 

For a protected rcr123 in contrast, while the same can happen, its less common as rechargables tend to get dmm'd and mismatches more likely to be caught. The protection also helps if run away was an issue.

I tend to prefer the IMR RCR123 versions as they can do higher amps than the other two options, and the don't tend to go


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## degarb (Dec 25, 2013)

inetdog said:


> Lithium primaries in series can still fail spectacularly if unmatched cells are used. They do not have under voltage and reverse charge protection.
> 
> Sent from my XT1080 using Tapatalk



It seems to me that the second part (inetdog's second sentence) is the key. 

In parallel, the weak cell could take a charge from the strong cell: would this balancing be a bad thing as long as protection circuit keeps current and voltage in legal range.


In series, would not a protection circuit (low voltage cutoff) kick in and preclude any reverse charging?

Yes, certainly, you need a good quality cell, which would have a "real" protection circuit. Obviously, a light manufacturer could add protection between cells to bolster the cell protection. And, all bets off on people that insist on unprotected cells. (Hubris, in my eyes. Everyone makes mistakes.)


And back to OP... Why would anyone mess with 123s, unless you needed a keychain light? Even then, since you can't do much with that format, a singe AA is safer and make more sense to me, as an emergency light. 18650s rule for size/capacity over just about any other size liiion. Dual 18650s (the power of 8 AA, but closer to 3 AA weight) make sense to people like me with runtime at fairly bright levels. Single 18650 flashlights have there place, however if the Sparks single 18650 is as small as I think (from one video) I could see this light replacing any edc and serve as a headlamp. Probably same for zebra.


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## TEEJ (Dec 25, 2013)

degarb said:


> It seems to me that the second part is the key.
> 
> In parallel, the weak cell could take a charge from the strong cell: would this balancing be a bad thing as long as protection circuit keeps current and voltage in legal range.
> 
> ...



I use protected or ones with safer chemistry...but, its not all hubris by those that don't. For example, the amps that can be supported is higher on many unprotected cells, and those who use them, at least that I know long enough, do take appropriate precautions to enable safe use. Unprotected cells tend to be less expensive, so, you can also afford to have more of them on hand as needed.

Its a calculated risk to use ANYTHING that has the potential for , for example, many of us use a flammable solvent containing mixture (Gasoline) to get to work and back, drive our children to soccer, etc...even though its PROVEN that it can not only catch fire, but can also explode, etc.

We do tend to say, not smoke when fueling, avoid Pinto's, and take other normal precautions when using gasoline, and, despite the chemistry being potentially dangerous, the normal precautions, most of the time, are adequate, and we are OK with the risk/benefit ratio that we live with.

Its the same with cells.


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## degarb (Dec 25, 2013)

TEEJ said:


> the amps that can be supported is higher on many unprotected cells, and those who use them, at least that I know long enough, do take appropriate precautions to enable safe use. Unprotected cells tend to be less expensive, so, you can also afford to have more of them on hand as needed.



Interesting. The biggest argument to sway me that I hear against protected cells, is that they can be damaged, causing a short. (Shorts, heat, and charge state = bad) This can happen on a poorly designed light when inserting cell (who range in sizes), or dropping light.

My feeling is yes, initially, matching a brand of cell with light may be dangerous. But once you know what brand of cell works in your light, this danger goes away.... Then, the risk of light shorting (especially with corded headlamps) while near body is VERY LARGE, much larger than a light dropping, like, 20 feet and damaging a cell. 

My bias is that, probably, high current lights are mostly toys and not tools. And if your protection is prohibiting the high current, this is for a safety reason--maybe a multicell light is safer for you, then.... My other feeling is from a good vendor, the protected cells are still cheaper than good 4 AA rechargeables.... 


So, I am mostly in the camp that when you get a protected cell, be careful when first inserting it into any light. Hope it doesn't get damaged by a poorly designed 18650 holder. (My fenix tk35 has springs on both sides, which is best design, I suspect. While some holders from dx, can be a bit hard on cell insulation on insertion.)

I still feel largely un-swayed by unprotected arguments. And think these people are typical over confident people who don't understand anything under triple redundant protection is no protection at all. Triple redundancy is NASA policy, for example. Not sure how this life rule exactly applies here, but double is better than single protection. Human reliance is folly. The only thing that is certain with people, is that a mistake is inevitable. People that don't grasp this have deeper flaws mentally that blind themselves to their own limitations. Most of us grow out of this 12 year old mind-set, but not all, I guess.


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## TEEJ (Dec 25, 2013)

degarb said:


> Interesting. The biggest argument to sway me that I hear against protected cells, is that they can be damaged, causing a short. (Shorts, heat, and charge state = bad) This can happen on a poorly designed light when inserting cell (who range in sizes), or dropping light.
> 
> My feeling is yes, initially, matching a brand of cell with light may be dangerous. But once you know what brand of cell works in your light, this danger goes away.... Then, the risk of light shorting (especially with corded headlamps) while near body is VERY LARGE, much larger than a light dropping, like, 20 feet and damaging a cell.
> 
> ...





What are your triple redundancy precautions that you use to protect you from the gasoline in your car, and when you go to a gas station and others are fueling as well, etc?


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## mcnair55 (Dec 25, 2013)

I love this forum for all the scare stories about batteries,my advice use common sense and I reckon you will be fine.


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## degarb (Dec 25, 2013)

TEEJ said:


> What are your triple redundancy precautions that you use to protect you from the gasoline in your car, and when you go to a gas station and others are fueling as well, etc?



Good point. This is why a fueling vapor shroud and a sign "do not pump unattended" is a no brainer--cheap and no downsides. I suppose I rely on the fact that there is a very narrow and specific vapor to air mixture before combustion is possible. And 120 years of car design & fueling design. And the cost/risk posed to the manufacturer. Certainly, I am relying on others' auto design knowledge--less reflectively, perhaps, than with LiIons. Were the year 1913, ....

New technologies, shift the onus of protection onto user (as new gaps arise). A window breaker or two in glove compartment for starters-as moronically the consumer accepts power windows. Adding round blind spot mirrors. Not using your drink holders when driving. Of course, it all depends if I think about it, have the money to act, the time to act, have put enough thought into something, and am worried enough to buy that safety gadget.


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## degarb (Dec 25, 2013)

mcnair55 said:


> I love this forum for all the scare stories about batteries,my advice use common sense and I reckon you will be fine.




Common sense? I am not sure a new guy will know that Ultrafire is NOt a trusted name brand. Cheap cells may have faulty or absent protection circuits. Or the charger and battery that a manufacturer sends you, may not cut off at 4.2 volt. And high voltage, I wager, is main reason we hear of rechargeable explosion or venting ( I wonder what percent). 

Simplistic Warning(?): Heat, shorts of any kind (damaged cell/protection circuit, internal plating from under charge, water, or light short) , charge state (overcharge and undercharge). 

Solutions: Good charger, charge in fireproof container & attended, buy only certain brands (panasonic, aw, sanyo, samsung, I guess?), do not damage cell or protection circuit, keep cells between 4.2 and 3 volts (2.7 on high capacity). carry in plastic 18650 holders or in light so cells aren't damaged, keep away from over 130 F (I see this warning on my cells) over 300 (runaway will occur). 

The original reason I posted here, I suppose, is that I am not seeing the danger of a multicell light when sticking to a protected cell. With unprotected cells, absolutely. Unless the protection circuit is bad. Unless, someone knows something I don't. ... Yeah, sure a good manufacturer could add protection circuits of their own between cells. I only know of the vapsafe fuse as an add on protection (not soldered to cell), which would only help on light (load) shorts..


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## mcnair55 (Dec 25, 2013)

degarb said:


> Common sense? I am not sure a new guy will know that Ultrafire is NOt a trusted name brand. Cheap cells may have faulty or absent protection circuits. Or the charger and battery that a manufacturer sends you, may not cut off at 4.2 volt. And high voltage, I wager, is main reason we hear of rechargeable explosion or venting ( I wonder what percent).
> 
> Simplistic Warning(?): Heat, shorts of any kind (damaged cell/protection circuit, internal plating from under charge, water, or light short) , charge state (overcharge and undercharge).
> 
> ...



Strange how they sell product with no warnings then.UK retailer is doing a torch complete with 18650 and a mains and car charger for £30 Uk which as you know is cheap as chips and probably all it is worth but inside there is no additional safety warnings other than that is required by law.


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## TEEJ (Dec 25, 2013)

Warnings in the US are way above what you'd see elsewhere, from what I can tell.

Stanley Tools had toput a warning on their hammers that say you can cause injury or even death if you were to strike yourself or someone else in the head with the hammer.

Who can read the warning, and, yet, NEEDS to be told that?


IE: Hmmm, I will buy a metal thing that I can drive nails in with....but, unless it tells me NOT TO hit myself in the head with it, I guess it would be OK....

Hmmmm, there IS a warning about this, and, lookeee at that, it IS dangerous to hit myself in the head with it!

Thank GOODNESS I saw that warning label.

Whew.


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## thedoc007 (Dec 25, 2013)

skeeterbait said:


> Lithium, or any batteries for that matter, used in series where one battery has significantly different charge state, capacity, age, or internal resistance can cause one battery to exhaust before the other. This can result in the discharged battery receiving charge from the second battery in reverse. This can result in battery failure, leaks in alkaline, venting of hot toxic gas from lithium. Using a voltmeter, checking voltage of paired batteries, buying only quality fresh batteries, matching batteries of like age brand and capacity, use of batteries with protection circuits, all serve to minimize this risk. Also using lights that require only a single battery eliminates this risk. So of you are talking about switching from a two CR123 in series headlamp to a single 18650 lamp, then yes you are eliminating this risk.



One clarification. Checking voltage in CR123s is almost completely useless. It will display 3V when new, 3V at 50% and 3V at 10%. It tells you NOTHING until the cell is almost completely dead, at which point you'll already know due to reduced output.

That is exactly why a lot of reverse charging/venting with flame happens with multiple CR123 in series. There is no good way to check to see if they are well matched.


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## skeeterbait (Dec 26, 2013)

thedoc007 said:


> ... There is no good way to check to see if they are well matched.



I am of the opinion that CR123 can be safely matched using a load testing device. I use a ZTS MBT-1 to test lithium primaries including testing them streight from the box. I have yet to find a bad one out of the box but will not take a chance on it.


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## thedoc007 (Dec 26, 2013)

skeeterbait said:


> I am of the opinion that CR123 can be safely matched using a load testing device. I use a ZTS MBT-1 to test lithium primaries including testing them streight from the box. I have yet to find a bad one out of the box but will not take a chance on it.



You are quite right, they can be load tested, and that gives a decent idea of capacity. But a simple voltage check will do you no good at all. Thanks for the correction!


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