Better to use 2 CR123A or 1 18650 battery?

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FoxAdriano
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Better to use 2 CR123A or 1 18650 battery?

Just to know: if my flashlight indifferently uses as CR123A as 18650 batteries, what is better to use? That is is it better 2 CR123A or 1 18650 battery? What differences? THANKS

Shadowww
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1*18650 as it’s rechargeable.

FoxAdriano
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But CR123A too are rechargeable batteries.

Shadowww
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Nope, CR123A’s are LiMnO2 primaries.

HKJ
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I usual uses 18650 because they contain much more energy, i.e. longer runtime.

The exception is lights that are stored away for emergency usage, there real CR123 batteries (not rechargeables) are best.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

FoxAdriano
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You tell me CR123A are not rechargeable but why are there charger that can charge CR123A batteries too? May be do I make a mistake?

Shadowww
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CR123A are primaries, but there are also same-sized rechargeable batteries called RCR123 (also sometimes called "16340 batteries")

Pok
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CR123 = primary cell
RCR123 or R123 or …. R = rechargeable
…….

Depend on the driver.

FoxAdriano
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OK! They are the specs of my flashlight:
Operating voltage: 2.7V – 12.6V
It can be powered with 2 CR123A batteries, 2 RCR123A batteries, or 18650 li-ion battery.
I repeat my question: can I use the rechargeable RCR123A batteries? It seems that I can, therefore: is it better to use 2 RCR123A or 1 18650 rechargeable batteries?

Shadowww
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2*RCR123A = 2*2.5 = 5 Watt-hours
1*18650 = 10+ Watt-hours

So 1*18650 will give you double (if not more) runtime comparing to two RCR123A’s

FoxAdriano
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THANK!!

bfksc
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FoxAdriano wrote:
OK! They are the specs of my flashlight:
Operating voltage: 2.7V – 12.6V
It can be powered with 2 CR123A batteries, 2 RCR123A batteries, or 18650 li-ion battery.
I repeat my question: can I use the rechargeable RCR123A batteries? It seems that I can, therefore: is it better to use 2 RCR123A or 1 18650 rechargeable batteries?

My light is similar in that it can use 2xRCR123 or one 18650 for rechargeables. Often the higher voltage of the 2xRCR123 allows brighter maximum output, but if you don’t mind losing a few lumens in exchange for much longer runtime, then the 18650 is the better option. I use 18650 cells exclusively in my light for the added runtime (over 4x longer), and using single cells prevents any imbalance between multiple cell configurations.
JustFit
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FoxAdriano wrote:
OK! They are the specs of my flashlight: Operating voltage: 2.7V – 12.6V It can be powered with 2 CR123A batteries, 2 RCR123A batteries, or 18650 li-ion battery. I repeat my question: can I use the rechargeable RCR123A batteries? It seems that I can, therefore: is it better to use 2 RCR123A or 1 18650 rechargeable batteries?

It’s better to use 18650 , because out of a flashlight you want as much runtime as you can get …

1 × 18650 , let’s say with a minimum of 2500 mah real capacity -> 3.7 V x 2500 mAh = 9,250 Wh

2 X RCR123 ( 16340 ) , with tipical capacity of ~ 650 mah – 3.7 V x 650 mAh x 2 = 4,810 Wh

==> you have almoast 2 times more juice from one 18650 , than 2 X RCR123

Wink

Think twice, act fast! 

Shadowww
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Uh, JustFit, power is measured in Watts, mAh is measurment unit of capacity.
Also, 3.7V*2.5Ah = 9.25Wh, not 9.25W. Don’t confuse people :Р

Edit: thanks for correcting it :Р

JustFit
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Shadowww wrote:
Uh, JustFit, power is measured in Watts, mAh is measurment unit of capacity. Also, 3.7V*2.5Ah = 9.25Wh, not 9.25W. Don’t confuse people :Р

right Wink , and done .., thank you! Smile

Think twice, act fast! 

phantom23
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JustFit wrote:

1 × 18650 , let’s say with a minimum of 2500 mah real capacity -> 3.7 V x 2500 mAh = 9,250 Wh

2 X RCR123 ( 16340 ) , with tipical capacity of ~ 650 mah – 3.7 V x 650 mAh x 2 = 4,810 Wh

==> you have almoast 2 times more juice from one 18650 , than 2 X RCR123

Wink


More – at higher load RCR123 capacity decreases and actual runtime is about three times shorter than with 1×18650.
kramer5150
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18650 is best IMHO, if nothing other than for ease of field replacement and backup carry.
The only reason I can see 2xRCR123 being advantageous is if the light has flatter regulation at 8.4V than 4.2V. Not all lights are regulated at 4.2V.

FoxAdriano
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I’d like to buy Genuine Panasonic 18650 batteries by DXDealextreme but in their web page i read “SKU” 121444. I don’t like much this writing. What does it mean? May be they are not original? The link is: http://www.dealextreme.com/p/genuine-panasonic-18650-3100mah-rechargeabl...
Then: are they protected batteries?
Thanks for your news.

Shadowww
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SKU = Stock Keeping Unit, basically ‘alternative’ for UPC barcodes. It’s nothing you should worry about.

FoxAdriano
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Shadowww wrote:
SKU = Stock Keeping Unit, basically ‘alternative’ for UPC barcodes. It’s nothing you should worry about.

I have just noticed they are not protected batteries. I read “with Protection Board”, this is a different thing. Right?
Shadowww
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Uh, protected battery = battery with protection circuit board. So no, it’s not a different thing.

FoxAdriano
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But in that writing there isn’t “circuit” but only “Battery with Protection Board”. Therefore I can buy them because they are protected. Right?

scaru
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Yes, those are protected. 

FoxAdriano
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When I will receive those batteries: http://www.dealextreme.com/p/genuine-panasonic-18650-3100mah-rechargeabl...
how can I verify if they are protected or not?

HKJ
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FoxAdriano wrote:
When I will receive those batteries: http://www.dealextreme.com/p/genuine-panasonic-18650-3100mah-rechargeabl... how can I verify if they are protected or not?

You can check my review of the battery.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

x9cujo36
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You can see why people may find your answer wrong in the link below. In 2012 sure, but as time goes on we must also update info so that others are not mislead in 2021

https://www.surefire.com/products/parts-accessories/batteries/sflp123-ba...

ggf31416
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LiFePO4 has low capacity, its main advantages are higher reliability and ability to handle high current, LiFePO4 isn’t new, it already existed back in 2012, that product it will be useful for some people but for most flashlight uses 3.7V/4.2V Li-Ion is superior. The ones in the link have a capacity of 450mA @ 3.2V = 1.44Wh, a good 3.7V 16340 may have 3.2Wh, an 18650 may have over 12Wh

Edit: added 18650 comparison, fixed typos.

Firelight2
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Single-cell is always safer than running 2 cells in series.

With 2 cells in series, there is a risk they don’t deplete at the same rate. If one cell empties before the other it might end up reverse charging the depleted cell. A number of people reported their flashlights exploding when running 2xCR123 because of that.

A single cell is much less risky.

turkeydance
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as HKJ posted above:
“The exception is lights that are stored away for emergency usage, there real CR123 batteries (not rechargeables) are best.”

is this still valid in 2021?

some of my friends/relatives have flashlights stowed in their cars for emergencies.
some have been there for many years without any use. some will never be used.
but…..they should be reliable if needed. will CR123 do that better than 18650?

Hank33
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I’m curious about CR123 batteries too but more so the rechargeable RCR123 ones. Few years ago I used the green wrap ones from Ebay. Seems those were the only rechargeable ones around.
Is there a better rechargeable CR123 brand out today somewhere??