Battery Types

The topic of batteries would seem to be a fairly simple subject. I purchased some tactical flashlights that use a more specialized battery and I wanted to see if I could use a rechargeable battery. This seems like a pretty simple question. What I found was a very confusing and complicated battery landscape. Here are some of the more common batteries:

AA 1.5v Smaller devices including camera strobes, flashlights, etc.
AAA 1.5v Smaller devices including headlamps, flashlights, etc.
CR123 3v Used in most tactical, high-powered flashlights.
RCR123 3.7v Rechargeable version of the CR123. These normally output a higher voltage and I do NOT recommend using these batteries in flashlights that were not designed to use them. The higher voltage could damage your flashlight.
C & D 1.5v Used in larger flashlights, lanterns, etc.

These are standard batteries and things get complicated after this.

Type Composition Voltage Size mAHr Comments
AA Alkaline (d) 1.5v
Alkaline (r) 1.5v
NiCad (r) 1.2v
NiM (r) 1.5v
CR123 Lithium (r) 3.0v 0.64″ x 1.3″ 1400
RCR123 LiFePO4 (r) 3.7v 0.64″ x 1.3″ An ICR battery includes circuit that makes the battery¬†appear as a 3v cell.
16340 Lithium (r) 4.2v max
3.7v nominal
0.71″ x 1.3″ 550-700 Similar to¬†CR123 but slightly larger diameter.
16340 LiFePO4 (r) v Similar to RCR123s and uses safer chemistry but outputs lower voltage.
18650 (r) 3.6v – 3.7v 69.2mm x 18.4mm Looks similar to a large AA battery and used in a number of rechargeable tactical flashlights.
ICR & IMR (r) 4.2v max
3.7v nominal
IFR LiFePO4 (r) 3.6v max
3.2v nominal