Newb build suggestions - L2m base, XM-L2

LED Flashlights – General Info 18650 Flashlights
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Hi All

This is a partial repost from a thread I started in the BLF General discussion… because it is more specific I thought I would post it over here as it is specific to 18650 flashlights… (if this shouldn’t be here mods pls delete… thanks!)

Ok… So I think I might try to make a flashlight from parts… just for fun and to give it shot (I’m more used to modding and building watches so this is a little different)…

I am thinking Solarforce L2m body with 1 mode XM-L2 single mode 3v-18v from KD ( http://kaidomain.com/product/details.S021214), and 18650 tube extender (from Solarforce as well). The plan is to make the brightest light in my small collection (Tank007 e09 s3, LD01, Saber 1a), that I could edc in single battery format, or make something with some punch and duration in a two battery format. I may pick up the XM-L2 5 mode as well (I like the idea of a L-M-H set-up, has blinkies but there is no 3 mode that I have found).

What I was wondering was……… will I actually get better duration with 2 batteries and the 1-mode XM-L2 drop-in, or will it just be brighter (since it is 3v-18v)?

Also, are 3.7-4.2v drop-ins are for single batteries only and 3v-18v drop-ins are for single/multiple batteries? My confusion comes in that if the drop in has a regulated circuit, then do I need a 3v-18v drop-in, or could I still use two batteries with a 3.7-4.2v drop-in?

Lastly, how big of an issue is heat going to be? I am using the XM-L2 drop-ins available at KD… (they don’t have any specific specs as to which 7135*x) I am a total newb at this so your wisdom and experience are very much appreciated!

Thanks!!

:slight_smile:

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anyone?

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the 4.2v max dropin si probably direct drive with modes so only one 18650 (or 16340, 18350) should be used and it will be bright and hot for a shorter duration (~3a for 45min for example from good 18650)
3-18v dropin is regulated above ~4v and should remain it’s brightness with two batteries (cr123, liions) for a longer duration and has a 2a output
it will start to fade with one liion after 20-30min
so it’s up to you what you choose :slight_smile: for me modes are more useful most of the time but sometimes flat regulation and battery choice is good too

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If the driver is built to take the voltage of two cells it won't be brighter with two, just longer run time. If the driver's direct drive on high and you give it two cells then yes in that case it will be brighter... until it pops something. Are there any 7135 drivers that aren't regulated on high? Isn't that the whole point?

The only 'real' drivers I have are these and though they are spec'd as "2.8-6v" they run fine from two CR123s, but also two 16340s. Those push less current than 18650s though, obviously, so it might not be happy with the same voltage from the bigger cells, but I don't have a compatible host to try it that way. So there is definitely some wiggle room as far as input voltage goes.

My personal choice would be to keep the light in single cell config and carry a spare cell with me.