Not to seem dim but i have no real idea how all these lithium batteries compare size wise.
I.e i know an 18650 is roughly the same as 2 cr123/16430 but what about the rest, also how do they compare to alkalines ?
cheers for the help
Charles
14500 = AA
10440 = AAA
It breaks down to the first two numbers = Dia So 14500 is 14mm Dia and the remaining 500 is length , or 50mm long
That means 10440 is ? 10mm Dia and 44mm long
Yeah , it should probably have been 1450 and 1044 , but it is what it is .
AAA 10mm x 44mm long (10440)
AA 14mm x 50mm long (14500)
CR123 16mmx34mm long (16340)
18650 18mm x 65mm long (18650)
C 25mm x 50mm long (25500)
D 32mm x 62mm long (32600)
the last 0 says that it is a cylindrical cell. i.e., it is round.
There are some pictures around, but basically
15270 = CR2
14500 = AA,
10440 = AAA,
26500 = C,
32600 = D
The first two numbers are the diameter, the other two the length and the "0" is because of the shape, a cylinder.
14500 -> 14mm diameter x 50 mm length
old4570 is the fastest of the west 
:)
thanks old that was lightning fast !!
What about this one 17670 !! is this a special size ? i've not seen any flashlights using it
Many CR123x2 lights will take a 17670, but not an 18650. Like every Surefire out there - they won't take an 18650 till bored out.
The Romisen RC-F4 is another example, as is the Fenix P3D
It is also known as 4/3A size and lots of older laptops used 4/3A NiMH cells in their battery packs.
Cool cheers Don
In reality, most li-ion batteries are longer than they are supposed to be, especially if they have a protection circuit. Like I have some 18650's that should be 65mm long and they are closer to 68mm long.
The Quark 2xCR123A lights use 17670's too or you can buy a bored out tube that will take 18650's.
What you have to remeber is that none of these cells are really made for flashlight, it's more that flashlights were made to fit cells that were availlable.
Certainly most of the development for 18650's was for them to be used in laptops, I wonder if that is still the focus of new research or if that is all going towards powering electric cars.
Of to school he must go ..
Anyhow , 17670 is often a direct replacement for two 16340 , and 18650 requires 18mm tubes ..
Some lights are 17mm as they were designed to accommodate two CR123A batteries .. So unless you have a lathe or some other way to bore out a body , many chose to simply run a 17670 instead .. [ Dual Li-ion can be problematic and single cells are much safer ]
This is very informative...I suppose it's the basics but for a new person, this really helps a lot...thanks!
Dave
ha ,it is what it is. Product code comparative table should be need.
The last 0 means it is a cylindrical cell. I can't remember the other form-factor codes.
So my take on what I’m reading today, if I have a flashlight that takes 1, 18650 I can use 2. CR123a ?
Many lights allow this and many don’t.
They will fit but the voltage range for the driver has to support the 6.0 volts from the twin cells.
You may also want a sleeve to prevent battery rattle.
Yes = for the size, give or take a mm.
But = look closer at the light you have in mind.
The Surefire 6P or 6PD is sold incl. 2 * CR123A primary batteries. That is 2 * CR123A = 6.0V min.
The 6 stands for …… 6V. If you bore out the body, you can accommodate 1 * 18650 = 4.2V max.
The other way around is not always safe. Some drivers (etc) are intended to operate at 4.2V max.
6 Volt is almost 50% extra. Some equipment can survive that, others don’t.
But why, except with intention of back-up, would you replace rechargeable batteries with expensive primaries.
Some drivers take advantage of 2x16340 for added output.
Excellent use of primaries in an old 18650/2×CR123 light for a glove box or emergency.
Not always, this is a 380mm long cell and the last 0 is part of the number “380”.
