How do I tell if my new U2 will accept 18650?

Gern Blanston · Sep 20, 2006

I bought a U2 that was the display unit at Cabela's, so it might be an older model that will use a rechargeable battery.

How do I determine this without buying a rechargeable battery and seeing if it fits?

TigerhawkT3 · Sep 20, 2006

You could try measuring the ID of the battery tube with a set of calipers (I got mine here). An 18650 cell is 18mm wide ("18"), 65mm long ("65"), and round ("0"). If your light has a plastic spacer, you'll be able to use an 18650 after you remove it. If the ID measures smaller than 18mm, without any spacers, you're out of luck. You could try using a pair of 3.0V RCR123As (with significantly reduced runtime), if you like.

dizzy · Sep 20, 2006

If you take the head end off and you see a plastic liner inside the battery tube, that can be removed to accommodate the 18650. If the tube has no plastic liner in it, check to see if a cr123a cell is very sloppy in the light body. If it is, it will probably hold an 18650 without any modifications.

Gern Blanston · Sep 21, 2006

I don't have a plastic sleeve, but there is a little wiggle room for the batteries. My serial number is A11078 if that helps.

cheapo · Sep 21, 2006

i am afraid you're out of luck.

-David

TheSteve · Sep 21, 2006

Surefire serial numbers don't always indicate a build date/order but in the case of the U2 bodies I think its pretty safe to guess based on your serial number 18650s will not fit.
The plastic sleeve was introduced sometime around A08000, anything newer without a plastic sleeve should be the newest body that doesn't fit them.

dizzy · Sep 21, 2006

Gern Blanston said:
I don't have a plastic sleeve, but there is a little wiggle room for the batteries. My serial number is A11078 if that helps.

It does not appear, with that serial #, that the 18650 will fit in your light. You would need about 2 mm of wiggle room for one of those to fit in that body. Sorry about the bad news.

Gern Blanston · Sep 21, 2006

Oh well. (sigh)
It's still a great light.
Thanks for your help!

How do I tell if my new U2 will accept 18650?

Gern Blanston

Newly Enlightened

TigerhawkT3

Flashlight Enthusiast

dizzy

Flashlight Enthusiast

Gern Blanston

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cheapo

Flashlight Enthusiast

TheSteve

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dizzy

Flashlight Enthusiast

Gern Blanston

Newly Enlightened

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