My silly AA to CR2 light "conversion"

I have a generic Cree AA light that I noticed I could have a little fun with. The tail cap and head screw off, allowing me to remove the main barrel of the light (that piece isn't shown in the photo).

With the tube removed, and the right size rare earth magnet attached to the tail end of the battery (I was informed using the positive end could cause a short), it now makes contact and becomes a fun little CR2 light since two AA batteries will put out about 3.0V (alkalines) or 2.4V (NiMH) and the CR2 battery also puts out about 3.0V.

Actually I tried an AW 3.7V 14250 battery too as shown in the photo, which works also, and it didn't burn out the emitter and was brighter.

It makes a nice CR2 light with good throw. The beam shot is of our basement wall from about 20 feet. The head is now about half the length of the flashlight and has a very deep reflector which accounts for the tight beam profile.

Thats a fun experiment!

Am I reading the CR2 correctly, 300mAh... I'm guess the AA's would provide 2.4V at 2500mAh... meaning 1/8 the runtime on the CR2.

Cool little pocket rocket.

The circuit must have a tolerance to li-ion because 3.7v is the nominal voltage. In fact, when fully charge, the cell reach 4.2v.

derfyled said:

Cool little pocket rocket.

The circuit must have a tolerance to li-ion because 3.7v is the nominal voltage. In fact, when fully charge, the cell reach 4.2v.

Click to expand...

Seems like it since it takes at least a few seconds before the voltage declines to 3.7V which would be long enough to blow out something.

creegeek said:

Thats a fun experiment!

Am I reading the CR2 correctly, 300mAh... I'm guess the AA's would provide 2.4V at 2500mAh... meaning 1/8 the runtime on the CR2.

Click to expand...

Yes, you're reading it correctly, it's 300 mAh. Since this is just an around the house light I can always put in a new one or recharge.

Positive end will cause a short. I had that happen to a King Kong 26650 I was pulling out of a Maglite. S*(^&^ Got real fast! I will never do that again with out gluing them. Lucky I was outside and when I threw the battery when it landed in the road it dislodged the magnet.

Wow, that sounds pretty dramatic. I actually tried it on the positive end as the magnet is pretty small and nothing happened, but as I know better anyway I'm doing it the safer way.