# CR123 noob questions



## Spotpuff (Dec 3, 2007)

Forgive me if any of these questions have been asked and answered before (I'm sure they have); did a search but there's a ton of threads and discerning relevance was a bit tough.

I have a few questions about CR123 batteries. I'm thinking of getting a Fenix T1 with some rechargeable CR123's.

1. Are RCR123 batteries just rechargeable CR123's? Makes sense to just prefix with an "R" right?

2. Are unprotected cells are bad since they can become unusable after over discharge?

3. Do different brand batteries work with different brand chargers?

I am thinking of ordering the batteries from www.fenixtactical.com . They only carry 2 brands: Tenergy and Ultrafire. I'm trying to decide between the batteries because they have different rated capacities (which could be marketing, who knows).

The prices are:

Tenergy Charger w/ 4 batteries (doesn't say protected or unprotected):
$65

Tenergy Protected 2xRCR123 900mAh: $16

Ultrafire Universal or RCR123 only charger are both $22 each.

Ultrafire Protected 2xRCR123 750mAh: $20


The Tenergy charger comes with 4 batteries, so if I go with that charger I have to get Tenergy batteries. I'm assuming the Tenergy batteries are protected because on this page http://www.fenixtactical.com/tenergy-rcr123a-battery.html it says full PCB protection against over discharge. So they have 150mAh on the Ultrafire ones supposedly. However the charger seems overpriced, so getting the batteries separate with an ultrafire universal charger seems like the best option but again, I don't know if the cells will work with that charger because they are different brands.

If anyone can help me sort this out let me know!


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## Kiessling (Dec 3, 2007)

No problemo, ask away 

1) No, they are not. RCR123 or R123 are Li-Ion based and have 3.7V instead of 3V and a different behaviour under load. There are some 3.0V R123 though.

2) No, they are bad because there is a very realistic venting hazard, especially if the user dosn't know how to handle them. Those are dangerous cells. Apart from that, you are right with your point.
I admit though that fathooming the danger of cells vs other cells is way over my head.


3) I don't know, but I would be VERY VERY hesitant to try this without a confirmation from someone who really knows first. Some real expert, not an armchair user that does it and it didn't kill him (yet).

bernie


P.S.: as I don't use Li-Ion and never will, I really don't know why I am jumping in here. But I did


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## Spotpuff (Dec 3, 2007)

The fenix tactical website says the Tenergy 900mAh protected cells start at 3.6v but drop to 3-3.2v within 12ms... I wonder if that's every time they're activated or like, 12ms total, per charge?

Is the 3.6v "burst" harmful for lights or is that pretty standard?

And why the heck is the voltage higher than just lithium batteries? So confusing!


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## mdocod (Dec 3, 2007)

different chemistries make different voltages. Alkaline Manganese makes about 1.5V, Lithium Manganese Dioxide makes about 3.0V, while Lithium Cobalt Oxide cells are about 3.7V (that's "li-ion" chemistry). 

When they take a rechargeable chemistry like Lithium Cobalt Oxide and want to make a cell that it more compatible with devices that use primary Lithium Manganese Dioxide cells, they slap a voltage regulator on the end of the cell that "clamps" the output voltage down to around 3.0V,.. The cells end up wasting a lot of power into heat as the voltage shunting is done in a less than ideally efficient manner. Also since it takes up some of the space in the cell, the cell is even lower capacity to begin with. When you test the "open circuit" voltage of the cell, you read high voltage than working voltage because the voltage regulator doesn't really "kick in" until you start pulling a load. The 12ms is just the maximum time expected for the regulator to react to the load and shunt the voltage.


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## saeckereier (Dec 4, 2007)

Spotpuff said:


> Forgive me if any of these questions have been asked and answered before (I'm sure they have); did a search but there's a ton of threads and discerning relevance was a bit tough.


You are forgiven  Now really, most if this can be found here already and I really urge you to check the informations available here on the use of Rechargable LiIon Technology. But first here are your answers, as a regular LiIon User I am quite sure that these are adequate:



Spotpuff said:


> 1. Are RCR123 batteries just rechargeable CR123's? Makes sense to just prefix with an "R" right?


No actually it doesn't make sense. It's just a habit that developed because of the nearly identical sizes. As has already been explained above, the nominal voltage of a CR123 is about 3.0V and of an 16340 LiIon cell is 3.7 V (which is the real name of it, 16 being the diameter in mm, 34 the lenght in mm and 0 being the identifier for cylindrical shape) As it also has been already mentioned, they react differently under load, the LiIons voltage will not drop as much as the CR123As (CR123A being the correct name for the CR123). This two factors together mean that you may not use 3.7 V cells in a 3.0V flashlight unless the flashlight specifies that it's ok to use Rechargable LiIon cells. (e.g. Incandescent bulbs will flash in an instant, LED drivers may let out the magic smoke)

Still, there exist 3.0V LiIon cells but they use a tiny circuit to get the voltage down to 3.0V which is bad, reasons are listed further above (I'd not consider using those, there is an alternative which I am going to explain later on)


Spotpuff said:


> 2. Are unprotected cells are bad since they can become unusable after over discharge?


ALL LiIon cells should NEVER be used after over discharge. The protection circuit will (usually) shut off the cell when a certain voltage level is needed. It is not recommended to rely on this mechanism. Now here comes the biggest risk of LiIon chemistry:

LiIon is an inherently unsafe chemistry. Cells, only once overdischarged, become chemically unstable and can go *poof* at a very unfortunate moment. It is advised to check every cell by hand after deplation that the open circuit voltage did not drop under 2.8 V. 

The same happens once overcharged a single time, checking the OC Voltage immediately after charging is advised, Once higher than 4.2V (+/- 0,05 V) the cell becomes unstable too. LiIons aren't very tolerant to over(dis)charge and when they fail, they do so violently. They should never be charged unobserved and taken immediately of the charger. If you really want to use them, take the time and inform you well, plus invest in good cells, AWs cells or Pila cells might be a good choice. As always with great power they come with great responsibility on your side ( ;-) ) The checks I mentioned are obligatory to enure safe operation.


Spotpuff said:


> 3. Do different brand batteries work with different brand chargers?



Generally yes. You MUST NOT mix 3.0 V chargers with 3.7 V ones. If a 3 V cell gets charged in a 3.7 V charger, well there was a thread somewhere around here, the results were not nice.. But it is possible to use an XYZ 3.7 V charger with any 3.7 V cell.



Spotpuff said:


> I am thinking of ordering the batteries from www.fenixtactical.com . They only carry 2 brands: Tenergy and Ultrafire. I'm trying to decide between the batteries because they have different rated capacities (which could be marketing, who knows).


IIRC Tenergy is known for inflated claims. I use UltraFires sofar without problems, but others have experienced DOA problems, and I probably am just finding out about one now with a cell I hadn't used until yesterday. If you are going to order UltraFires, be aware that DealExtreme offers them as well as the charger for adecent price with free shipping, it will just take ages for them to arrive at your door. 

So now that I answered your questions, you might want to have a look for LiFePo4 cells (Sold by DX, KD and certainly others who I don't know) They use an inherently safe chemistry which means that the cells can't explode which is a good thing. Plus they are 3.0 V cells so it should be safe to use them in place of the CR123As, they should be safer to use than non rechargables actually. Disadvantage: special charger is needed (3.0 V LiIon will work) and the capacity is even worse than 16340 LiIon which is already worse than CR123As. There are few people who have tried them yet, but the specs sound promising in my opinion..


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## Spotpuff (Dec 4, 2007)

Thanks for the responses...
According to people in the T1 thread the T1 will take RCR123's. So the 3.7v shouldn't be an issue, although Tenergy states their battery voltage drops from 3.6v to 3-3.2v in 12ms, hence why I was wondering if that initial burst is ok, but it sounds like most LEDs will accept the higher voltage anyways so it shouldn't be a problem.

It appears the "ultrafires" on fenixtactical are actually AW cells (at least that's what's pictured); that's a completely different brand right? IIRC someone on this forum was selling AW cells in the marketplace at $6 a pop for the RCR123s.

Thanks for tkaing the time to answer the noobtastic questions... sounds like lithiums just have different voltages and can blow up or die from overdischarge. But otherwise they're like any other battery.

Another quick question in general: Why do NiMH AA's have like 2000-2600mAh and LiIons RCR123's only have 750 mAh? Seems like a huge gap in power storage there... I'm assuming it has to do with voltage since the AA's are only 1.5v, but still it just doesn't seem right.


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## saeckereier (Dec 4, 2007)

Spotpuff said:


> It appears the "ultrafires" on fenixtactical are actually AW cells (at least that's what's pictured); that's a completely different brand right? IIRC someone on this forum was selling AW cells in the marketplace at $6 a pop for the RCR123s.


Well AWs cells got their name because they are sold by someone called AW on this forum and are regarded as one of the best commonly available cells. I don't know about that shop, probably worth checking the sales thread for pricing and shipping.. (EDIT: Btw, I am lazy, but not too lazy to click a link if provided  I just had a look, the pictures are AW cells, but the pricing and the description lead me to believe they are UltraFires and the picture was only stolen, but that's just a guess)


Spotpuff said:


> Thanks for tkaing the time to answer the noobtastic questions... sounds like lithiums just have different voltages and can blow up or die from overdischarge. But otherwise they're like any other battery.


Yes, if you use them just keep in mind that the danger is real. Most failures seem to occur while charging. So keep an eye on them, I just stressed these points very much, because I read enough posts about people who got to know those things just in time. There's a reason why these are not widely in use (speaking of single cells)


Spotpuff said:


> Another quick question in general: Why do NiMH AA's have like 2000-2600mAh and LiIons RCR123's only have 750 mAh? Seems like a huge gap in power storage there... I'm assuming it has to do with voltage since the AA's are only 1.5v, but still it just doesn't seem right.


You're assuming right. The amount of power that is inside a cell is measured in Watthours (Wh) Watts (talking about DC) are the product of Voltage and current ( U * I ). So if you do a comparison on these, you will see that they're not so different. To compare battery types, Wh/kg is normally used, too.


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## Spotpuff (Dec 4, 2007)

All I remember from high school physics is V = IR and P = IV (power = current * voltage). I could do some sort of dimensional analysis to convert mAH to Watt hours, but I am not smart enough so I won't try 

Looks like you did the work already but here's the link in case people are wondering 
http://www.fenixtactical.com/ultrafire-products.html#RCR123A-battery

So yeah... I dunno. $20 for 2 RCR's seems expensive. Are they going to be substantially better than the Tenergy's?


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## saeckereier (Dec 4, 2007)

Spotpuff said:


> All I remember from high school physics is V = IR and P = IV (power = current * voltage). I could do some sort of dimensional analysis to convert mAH to Watt hours, but I am not smart enough so I won't try



Well it's easier than it looks like. I wasn't clear enough in my last post. The Watt hours can be calculated as:

Wh = Voltage * Capacity in Ah (Highschool physics won't help you very much, as Ah is not really a SI-conform unit of measurement..) I'm not totally sure, whether this is right, but using common sense it should be.

Looks like you did the work already but here's the link in case people are wondering 
http://www.fenixtactical.com/ultrafire-products.html#RCR123A-battery



Spotpuff said:


> So yeah... I dunno. $20 for 2 RCR's seems expensive. Are they going to be substantially better than the Tenergy's?


Unfortunately I am unable to aid with this one, it's hard to say as I know neither.


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## Bullzeyebill (Dec 4, 2007)

Well, now that you know the dangers of RCR123's I will say that I have used them for 2 years with good luck. The only RCR123's that I use are unprotected Powerizers. Early on I used them X2 with the Surefire P91 LA and noticed that some cells were not looking well, actually some swelling noticed. I put these away, never to be used again, and have limited my Powerizers to 1.5 amp draws. No problems since then. I do monitor my Powerizers closely and check charging termination voltage. I have two LiIon chargers that both terminate the charge at 4.2 max, one for RCR123's and one for the longer variety LiIon's. When using LiIon batteries, as soon as I notice the light dimming or dropping out of regulation I switch out the battieries. LiIons are my batteries of choice when I have lights that work with them. I do notice that I have been gravitating back to CR123A based lights that can also work well with 2XNiMH's.

I should add that I use my RCR123's is series when the flashlight has a buck converter. This usually keeps the current from the batteries at 1 amp or less.

Bill


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## Spotpuff (Dec 4, 2007)

Ah you're right that IS easier. If P = IV then WH = IVH

So 3.7v @ 750 mAH = 2775 mWH
And 1.5v @ 2000mAH = 3000 mWH

So they are pretty close in terms of capacity, though the higher capacity NiMH's will outdo the LiIons.


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## Bullzeyebill (Dec 4, 2007)

Check you math. You are not using decimal points right. For example it is .750 amp/hrs.

Bill

Whoops I see your mil/wt/hrs. Sorry.

Bill


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## DM51 (Dec 4, 2007)

@ saeckereier - you have done some useful reading on this subject and the information you have given Spotpuff is good. You may find some additional information on Li-Ion cell charging helpful.

Not all Li-Ion chargers are suitable for all Li-Ion cells. Li-Ion cells needs chargers specific to their particular chemistry and capacity. For example, a charger designed for 3.7V Li-Ion cells is not suitable for 3.0V ones.

The capacity of a cell is given in milliamp-hours (mAh). An 18650 cell will typically have a capacity of 2200mAh, an R123 (a.k.a. 16340) cell would be 750mAh and a 10440 cell 320mAh. 

Some manufacturers blatantly overstate the capacity of their cells. Any figures that significantly exceed those given above should be regarded with suspicion (the more the claimed figures are inflated, the worse the cells are likely to be). 

The safe charge and discharge rates for cells are given as a multiple of a figure known as ‘C’. Li-Ion cells should ideally be charged at 0.7C. The charge rate should never exceed 1C.

C is a figure for current, measured in mA, which is easily obtained from a cell’s capacity. Using the figures above, just knock off the ‘h’ and you have the figure for 1C: it is 2200mA for an 18650, 750mA for an R123, 320mA for a 10440, etc. This is therefore the maximum safe charging current in each case for that capacity cell.

Budget 2-bay Li-Ion chargers have fixed outputs that vary between 450-800mA per bay. You can immediately see from the figures for 1C above, that these chargers should not be used with cells smaller than 14500 / 16340 size. 

10440 cells should therefore be charged on a charger with a lower output. 

Your recommendation for AW’s Li-Ion cells is a good one. They can be found here.


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## saeckereier (Dec 4, 2007)

DM51 said:


> @ saeckereier - you have done some useful reading on this subject and the information you have given Spotpuff is good.
> 
> [...]
> 
> Not all Li-Ion chargers are suitable for all Li-Ion cells. Li-Ion cells needs chargers specific to their particular chemistry and capacity. For example, a charger designed for 3.7V Li-Ion cells is not suitable for 3.0V ones.


Well, I mentioned it, it wasn't very easy to see as I forgot to put a closing quote tag at the right place.. ;-) Thx for pointing it out again!


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## sawlight (Dec 8, 2007)

OK, I feel like a moron right now!!! I have read and researched looking for good RCR123 batteries, and feel like I know less now than I did!!!
I have a Novatac 120p comming, I don't want to do the battery reset thing everytime I need to change the battery, or if the rechargable is dead and I need to install a primary to get going now.
So I think? sticking to a 3v is the way to go, right?
Is there that much difference between them that make one brand better or safer?
Certain things I don't mind playing with, I think learning this light is going to be enough, I don't want to worry about doing something stupid with the batteries/charger!!
Are RCR's really that unstable/unsafe?
Any recomendations for me on two batteries and a charger?
Am I better off just running primaries?
Sorry, lots of questions!!!


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## cave dave (Jan 27, 2008)

sawlight said:


> Is there that much difference between them that make one brand better or safer?



Absolutely, we are talking about the same kind of manufacturers that will coat children's toys in lead paint or GHB. Some of these cell manufactures have been shown to lie about there products or cut safety corners in order to produce the cheapest possible products.

There are also unsafe primary CR123's out there so buyer beware.

Anyway for the $30 or so you would spend on a charger and two RCR123's you can get a 24 American made Battery Station "Blue label" CR123 primaries. That would last me 2 yrs or more.



> There is hardly anything in the world that some men cannot make a little worse and sell a little cheaper, and the people who consider price only, are this man's lawful prey. – John Ruskin - British Author & Writer


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