S/F U2 + 18650 Performance ?

How many of the U2 owners out there are using 18650 rechargables?

Do they fit inside the U2 without any modifications?

Will it hurt a U2 by using 18650's?

How does the performance/run-time compare to CR123 cells?

What are the best sources for 18650's and a compatable charger?

Thanks a lot

18650 is all I use in my U2. you will lose a little brightness, but gain huge runtimes and of course guilt free lumens.

U2 is one of the few lights designed for 18650. has low voltage support for li-ion.

I've been using 18650 in my U2 for a while,I havn't noticed reduced brightness though I'll defer to the experts that have meters on this subject.
The 18650 must be inserted from the front.It's no big deal it disassembles easilty.I got my batteries and charger from The Battery Station.

cy said:

you will lose a little brightness, but gain huge runtimes and of course guilt free lumens.

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:thinking: You don't mean runtime per battery, do you? I thought that a set of 123a's would power the U2 on high for about an hour, and the 18650 for about 40 minutes.

I have been using 17670's (pretty much 18650's) taken from an old laptop battery pack (free is a good price, if you can happen to scavenge some from an old pack ).

As Navistar says, 18650's fit without any modifications and will by no means harm the light as they don't provide as much voltage to the emitter. I do notice some decrease in output when using rechargable cells as compared to primary lithiums, but I'd say the difference is pretty negligable, especially when you consider the huge cost benefits.

Jtice reviewed the U2 here:
http://www.jtice.com/review/lights/u2/

and included a brief test (using a light meter; not integrating sphere) of output with an 18650:
"My U2 measured 1777 Lux on Level 6, and 177 Lux on Level 1, with 2 123 cells.
Output was slightly less, but longer runtime, using a 18650 cell. 1496 Lux on Level 6, and 89 Lux at Level 1"

-Brad

The U2 is alittle dimmer on a 18650 vs 2x123.

Hes does NOT mean that the light will be damaged, and dim over use.

I use only 18650s in my U2, and they are fantastic,
you won really notice it being alittle dimmer,
The runtime is wonderful.

~John

Can anyone post his own experience concerning runtime with a 18650 battery? Some people say runtime is shorter (like 40 min), others say it's longer (around 1h30min). I'm confused...

Erasmus said:

Can anyone post his own experience concerning runtime with a 18650 battery? Some people say runtime is shorter (like 40 min), others say it's longer (around 1h30min). I'm confused...

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Depend on the size of the cell and hot it is being charged. The LG2400 gives 90min for me.

Luna said:

Depend on the size of the cell and hot it is being charged. The LG2400 gives 90min for me.

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I have bought protected 2200 mAh 18650 cells from AW, are these about equal?

current draw from U2 as measured by fluke 87 is 1423 from 18650 on highest level. 812 milliamps at level two.

I'm running 2400 mah 18650 and get over 1.5 hours runtime on high. but most of the time I'm running at level two, which is not that much dimmer and will get close to three hours.

not really a runtime guy, so take my runtimes with large doses of salt

most of my long runtimes are done strapped to a bike helmet for night rides. carry two extra 18650 in sealed match tubes and you've got loads-0-capacity with you.

LG 18650's + U2 = about 90 minutes runtime.

What's LG?

Ditto ..... What's LG ? .......:thinking:

My AW unprotected 18650 fits loosely in my U2 - I wrap the battery with tissue paper to stop this.

Any one else find this to be the case?

Tom

"LG" is the brand, as in LG Electronics.

Lucky Goldstar

Check batteryspace.com

Should I buy "un-protected" or "protected" 18650 cells for the U2?

Thanks for all of the feedback.

if given a choice, always go with protected cells

I'm using bare 18650 and pila 168A both. but have got more bare 18650 simply due to costs.

with cheap protected cells recently available at cost close to bare cells. protected would be first choice

With the U2, you are perfectly safe with the unprotected cells.
But just dont try using them in other lights, unless you know they are safe.

The bare 18650 gets alittle more runtime,
but not a LOT.
Just be aware of what cells fit what lights etc,
as the 168A is fat, and wont fit many lights.

~John

Another U2 owner with AW's protected 18650's. It's a great thing, those guilt free lumens!

Can the U2 take 2 unprotected or protected RCR123s?