Single AA Flashlight Battery Substitutions?

[jasturbo02]

Does anyone know if 2 CR123a or 2 CR2 batteries are similar in size to one AA? I was wondering if I could substitute 2 CR123a's or 2 CR2's for a single AA in one of the DX flashlights. That way I could build a regulation circuit for 7.2volts. I've compared several pictures from the DX website but still can't tell by the pictures.

 

[Kenom]

No you cannnot use a cr123 unless the barrel your using is slightly larger. The cr123 is a few milimeters larger than the AA. However I did find on DX a 14500 which is the exact same size as an AA battery but runs at 3.6V.

 

[Benm]

Half-AA lithium cells (14250) exist (both primary and rechargable), though they aren't that common.

 

[morganclay1219]

As Kenom said, CR123s are about 2.5-3.5mm in diameter more than a AA (17mm for CR123 and 13.5-14.5mm for AA.) Two CR123s would be about 19.5mm longer than a AA anyhow. As for CR2s, they're 15mm in diameter by 27mm long, and AAs are 50.5mm long. So if you could eek out the extra 3.5mm in length to fit 2 CR2s, it would be a close fit for the diameter. Depending on the flashlight, this may be possible, but definitely figure out a way to get the CR2s out if it's too tight . Good luck finding something!

 

[jasturbo02]

Thanks for all the help. This is a bummer. I was hoping to get a cheaper flashlight as a host but now see I will have to pony up for the ones that take 2 AA's and use 2 of those lithium rechargeables. I've got a few other things in the works making my own housings that I will post if they work out.