New SF U2 Question.

Being very new to the forums, I have a 'newbie' question. I just bought a new SF U2 from Cabella's in Ft. Worth Texas (only place reasonably close that had in stock). From what I've read, I was expecting a sleeve inside, but instead it's definitely the aluminum body inside, with a short chrome looking section in the area just under the tailpiece (insert?). The 2x123's are a nice, slightly loose fit and will rattle some with a side to side shake without the tailpiece.

The outside of the box has the "2 to 100 Variable Lumen Output" designation, and shows model U2-BK-WH Digital Ultra Power Select. The back side of the box, under the Surefire URL and phone numbers, has the number 30-02-376.

I don't have any problems at all with the flashlight, has a very white (probably just a touch of blue) beam, perfectly centered and round, with maybe just a very light bit of doughnut at the center if you really look closely.

Completely happy with the light, but may want to convert to rechargeable batteries, and just wonder what I have... older version?... new version without sleeve??.. any disadvantage to the one I came up with??

Thanks, I appreciate any comments or info... Quinn

What's the serial number on the light?

You can get a great looking body from www.lighthound.com that is made by a fellow on these forums named Leaf. It is big enough to digest a 18650 battery which make the U2 run for around 1.5 hours (Maybe more) on the high setting. I have 2 of these and I am very happy with the way they look and function.

You should also be able to run the U2 with it's stock tube (I also have one without a sleeve) off of a 17670 battery. This is a little lower capacity so the runtimes are less than with an 18650 but I believe that you will still be very happy with the way the light performs.

Great choice in lights. I hope that you enjoy it.

-Goatee

It sounds like you have a newer version that you can run 17670 batteries. The I.D. of the tube has to measure a little over 18mm to fit 18650 batteries. The only disadvantage is that you will get less runtime than a 18650 battery set-up, but the same runtime as CR123 batteries using a 17670 battery.

digitaleos said:

What's the serial number on the light?

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It has a number under the right part of the 'Surefire' logo, A14542, I assume would be the serial number. Does that sound right?

Thanks for your response... Quinn

Yes, that is the serial number. I would definitely say you have the latest version, it will either take two cr123's or one 17670, or you can do as Goatee has suggested and buy one of the 18650 Leaf bodies from lighthound.

> ... I'll take a look at the Leaf body, sounds good... so far I really like the light from what I've seen... thanks.

FlashKat ... Hope you're right, thought I might have an older version of some sort... thanks.

Maybe I'll find out for sure, if digitaleos knows from the serial number. Looks like maybe I have a 17670 body, and can go to a Leaf body for the 18650. Better than I thought it might be, as far as going rechargeable.

Thanks for the info... Quinn

digitaleos said:

Yes, that is the serial number. I would definitely say you have the latest version, it will either take two cr123's or one 17670, or you can do as Goatee has suggested and buy one of the 18650 Leaf bodies from lighthound.

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Great! You guys are a tremendous help... thanks again... Quinn

If you use the 18650 battery then you may have to either use a magnet on the top of the positive end (I do NOT recommend) or extend the spring on the head (Be very careful) for the 18650 to make contact.
If you don't want to hassle it then buy the 17670 battery.

FlashKat said:

If you use the 18650 battery then you may have to either use a magnet on the top of the positive end (I do NOT recommend) or extend the spring on the head (Be very careful) for the 18650 to make contact.
If you don't want to hassle it then buy the 17670 battery.

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Is this what you need to do for the Leaf body to work with the 18650? Haven't checked, but thought the Leaf body might be made specifically for the 18650 to work as is... Quinn

It's not the body itself...The 18650 batteries have a flat top, so the positive side has a hard time making contact.
I would trust using these magnets: http://www.lighthound.com/index.asp?PageAction=VIEWPROD&ProdID=2677 Since you will probably buy the Leef body and AW 18650 battery from Lighthound I would add these magnets.

QuinnK said:

Is this what you need to do for the Leaf body to work with the 18650? Haven't checked, but thought the Leaf body might be made specifically for the 18650 to work as is... Quinn

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QuinnK said:

Is this what you need to do for the Leaf body to work with the 18650? Haven't checked, but thought the Leaf body might be made specifically for the 18650 to work as is... Quinn

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My Leaf body and AW 18650 cells worked "as is" with no magnets. I did have to slightly stretch the spring on the positive terminal, but besides that, it works fine.

A couple of things, 1 if you stretch the spring you will lose your reverse polarity protection, as that is the only protection not making contact with the cells, 2 use some jb weld on the magnet washers and they won't come apart, and if your U@ has a black inner bore its got a removable (albeit rather hard to remove) delrin spacer, if it's gold and the batteries rattle a fair bit, then its 18 cell size ready, now if you have a tight fitting gold colored inner bore then you need Leef's body.

Dont bother ordering prtected 17670 batteries as they will not fit in the new U2 bodies.

Thanks everyone for all the good info... it's nice to be able to find out everything you need to know when you have a question. Great forum!
It's good to know if I want to use the 17670 in the original body they need to be the 'unprotected' cells, also nice to know about the magnets available with washers for the Leaf body.

Many thanks... Quinn

An unprotected cell will be fine in the U2, and the light will fade to nothing before it overdischarged the cell. BUT, if you do leave the cell in the light and leave the light on, even though you may not see it the cell is still being discharged. I accidentally did this, and is discharged an 18650 down to 1.4 volts over a week or so. Into the trash can goes the cell - you don't want to keep using an overdischarged Li-ion cell.