U2 switch problems?

billgr

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i'm thinking of getting a SF U2. but doing a search, i found some posts indicating some bad tailcap switch problems. was that just early teething pains cause of a new design....or is it still a concern?

also, if i wanted to use rechargeables, could i use r123 cells in it?

thanks..........Bill
 

goldserve

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From all the reading i've done, you can use a 18650 cell but it will be a little dimmer on the highest level.

2 x RCR123 would probably kill it.

I just ordered a U2 so i can't comment on the switch problem.
 

TorchMan

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I don't know if the one I recently purchased was an older one or not, box says 2-100 lumens. Thankfully, I've had no problems with it. What kind of swithch problems were they? Did stretching the spring resolve them?
 

PacketStorm

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I've read a lot on the U2 and I don't recall seeing anything about any tailcap problems. (I'm not saying there aren't any, I just can't recall reading anything on it).

Now I *do* recall seeing some postings about the Nite-Ops Gladius (which is another light in the same category of lights as the U2) tailcap being a bit "fragile" and getting damaged if dropped tail first on a hard surface.

The only thing that caught my eye that could POTENTIALLY be an issue with the U2 is getting grit or sand caught between the dimming ring and the body.

Other than that, the U2 is one heck of an instrument. I wouldn't hesitate to purchase one. Just need to cough up the clams... :broke:

My .02 :)
 

goldserve

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Not to hijack this thread but is there a easy way to get the U2 to stand up in candle mode? IMHO, I think that is the only flaw of all the SFs.
 

cy

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it's my understanding only a few early release U2 had tailcap problems.

that's been resolved long ago.

don't use 2x R123. U2 supports 18650 which is at least twice the MAH capacity. 600 mah for each R123 and 2400 mah for 18650
 
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Pwdrkeg

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greenLED said:
Really?! COOL!! :D

I've been using the Pila 168A in my U2 for a while now and it works
very well. It has to be inserted in the bezel end. It is too fat to fit
in the tail cap end. The 168A is also 2000 mAH as compared to the
168S, which is only 1400 mAH.
 

greenLED

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Pwdrkeg said:
I've been using the Pila 168A in my U2 for a while now and it works very well. It has to be inserted in the bezel end. It is too fat to fit
in the tail cap end. The 168A is also 2000 mAH as compared to the
168S, which is only 1400 mAH.

:grin2::grin2::grin2::grin2::grin2::grin2:
You guys are such a bad influence...:nana::goodjob:
 

cy

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bare single cell li-ion usage is safe, especially if light is designed to support li-ion use.

U2 is one of few lights with low voltage cutoff protection.

since 18650 is one of most commonly used size. development is more advanced with 18650. 2,400 mah is becoming common.

look for mah rating to go higher yet on most commonly used cells. note creep up in ratings for NMH AA's.

has anyone experienced switch issues with current production U2's?
 

turbodog

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U2 info:

Works with 168s and 168a pila cells. INTIAL brightness is SLIGHTLY less than normal 123 cells. This changes after a few minutes when the rechargeable cell outperforms the primary cell.

18650 cells work also. Same SLIGHT initial brightness drop.

Basically, level 6 on the U2 is hanging on by a thread. Most ANY type cell will not hold level 6 at max brightness unless it is in absolutely tip-top shape. Maybe this will change as better binned emitters come out, and if SF incorporates them into the U2.

R123 cells work, sort of. They run the U2 at max; the lower levels do not work.

Initial models had a tailcap problem. As one of the first 2-3 people on the forum to own a U2 I have this theory: the tailcap is bottoming out on the nylon ring that holds the clip into place. SF's tailcaps rely on a good snug "tightening-down" to make electrical contact as the threads themselves are not the means of electrical conductivity.

The people who complained to SF and were shipped new tailcaps; I would like to measure these caps. I bet they are slightly shorter (by maybe 1 or 2 1/100ths of an inch) than the initial caps.
 

Geogecko

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I've had my U2 for about 6 months now, but got it off eBay, so there is no telling how old it is.

Anyway, after the first month or two, I noticed that sometimes I had a hard time turning the light off. Well, it got worse with time, so I eventually e-mailed CS, and just mentioning the problem, they asked for my address so they could ship me a new one. Had it within a week or so.

The new one works great.
 

Hoghead

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My U2 was from the first batch of U2s. It had a faulty switch. Sometimes it had to be clicked two or three times to turn the light on or off.

I called Surefire and they sent me a new switch. It took a week or two to get the new switch. They were very nice about it.

The new switch works OK.

litefuse also repairs Surefire clicky switches.

This U2 has a slightly cool tint and is very bright. This light must have at least a "W" bin Luxeon and maybe a "X" bin. No way would I send this entire light back and take a chance on getting a different head.
 

cy

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hogshead, very well stated!

my U2's history is almost identical to yours. very brite and white beam. putting out lumens equal to Xbin light.

Surefire sent me a new switch, no way I was sending my entire U2 back to surefire and risk not getting my original U2 back.
 
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