Looking for a 17mm Driver for 1 Li-Ion or 2 CR123's

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sween1911
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Looking for a 17mm Driver for 1 Li-Ion or 2 CR123's

I’ve hunted around and don’t see this exact item mentioned, so my apologies if this has been discussed before.

I’ve had success using drivers specifically for a single Li-ion battery. There’s great options like the QLITE and Dr. Jones H17Fx. I’ve built P60/D26 modules with both for myself and other people.
They max out at 4.35v.

My question is I’d like to build a module running a 3V LED like an XM-L2 or SST-40 that can take either a single 18650 or two CR123’s so I can use primaries as a backup.
There’s plenty of off-the-shelf lights like the Fenix PD35 or Malkoff Hound Dog 18650 that can work like that, but I’ve yet to find a 17mm driver that I can build into a module that would work like that.

Anyone have any go-to drivers they like that fit that criteria? Does it even exist?

Just want to ask to satisfy my morbid curiousity… if I run a Dr. Jones H17Fx on (2) CR123’s will it go up in flames or just bleed off the extra voltage as heat? Or could I run it on a lower output as long as it’s not on turbo? I’m unwilling to torch the one I have running in my trusty bored 6P.

Any hints, suggestions? Thanks!

Edited by: sween1911 on 08/05/2022 - 14:44
Marc E
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I believe (which means you’ll need to check for yourself) that 7135s can handle 2xcr123s but it’s the Atiny that can’t, and there is a Zener diode mod which involves putting a Zener diode inline with the Atiny’s positive power connection to burn off the extra voltage as you mention.
I’ve never done it or even researched it properly so def check the details for yourself but as the 7135s burn off the extra voltage that would get passed to the LED i can only assume they would run much hotter with a higher voltage so bear this in mind.

Edit: With the FET in the Dr Jones’ driver though the full battery voltage would get passed to the LED so i guess… poof

I have a couple of these drivers in lights:
http://kaidomain.com/Flashlight-DIY-and-Tools/Flashlight-Drivers/BD39-17mm-2200mA-3V-9V-1-cell-or-2-cells-Buck-Driver-Board

which work but have mode memory (which i don’t like) and i think i measured PWM on the 2 middle modes, it’s fast (not obviously noticable in use) but not fast enough for my liking.
Interstingly that driver in the link has 3 modes, i’m sure mine has 4 but i also have the larger 20mm version so i will try and check my info for you.
There is also a single-mode option available in the same link, and there are also single mode 1500mA and 1000mA drivers available too:
http://kaidomain.com/Flashlight-DIY-and-Tools/Flashlight-Drivers/BD39-17mm-1_5A-3V-9V-1-cell-or-2-cells-1-Mode-Buck-Driver-Circuit-Board
http://kaidomain.com/Flashlight-DIY-and-Tools/Flashlight-Drivers/BD39-17mm-1A-3V-9V-1-cell-or-2-cells-1-Mode-Buck-Driver-Circuit-Board

Scallywag
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7135s are rated for 6V max. Older, better examples of the 7135 could occasionally be coaxed to work above that, but they tended to “wear out” eventually. I haven’t found any “newer” 7135s that pull it off at all.
I’ve got a Convoy L6 with a FET+1 as proof.