I'm looking for a driver for (3) Li-ion cells in series. I want to upgrade my dive light build (UltraFire W200)
Qualifications:
1. input Voltage ~3-13V. it doesn't have to go as low as 3V though
2. Single mode or 2 modes (e.g. Hi and medium)
3. 2.5 - 4 amps
4. 17mm width board size
Edit: added PCB size
I think that's all. Thanks
Maybe this one from Fast tech will work for you? :bber:
There is no 3 cells to one XML driver with 17mm I can remember…
The driver TiVo linked is the only driver which is almost what you want, the driver board is about 19mm in diameter and 9mm thick…
The picture of the lamp shows AAs…length 200mm….have you really modded it to 3*18650s?
Not sure if a driver that size exists that is efficient enough to be worth the extra cells.
there are drivers out there... for example see this buck driver.
It wouldn't be for (3) 18650s, but (3) 14500s (AA size) 
This would give the light flexibility to use either Alkaline, Lithium primary, or Li-ion cells. I think that would be a nice option.
I just found this driver, but it's only 1.2A output. all the same: (LightintheBox , Airyear, chinaFlashlights, ColorApples)
nailbender makes P60 drop-ins. I should ask him about this... "Also available in a 2.2 amp (3.6-16volt) One level" (CPF thread)
Been looking a long time myself and they always seem to be out of stock or inefficient when tested.
Pick any two of those, and you're in business. All 4? Not a chance.
If you open up the driver end of the pill the 19mm driver should work. If its similar to the KD super P7(sold just about everywhere it seems) the efficiency runs ~85% on high See here
Those numbers might get better with multiple LEDs in series or running an mt-g2 but it needs a bit of overhead. I’ve used it to power LEDs in parallel from 6V and 8.4V nimh packs but run time never seemed to meet expectations.
The driver you linked is one of the ax2002 or similiar ones….and fills not your own specifications, it’s low current single mode and a buck driver….lol
But yeah it is 17mm…. :bigsmile:
These buck drivers can be resistor modded to some amps so it might reach your minimum specification of 2.xA, I believe fastech has a similiar one for 1.5$, I have tested with 6V but nothing above…no modes, no high current and not very good on low battery voltage…
What led do you use? This drivers need around 0.5V higher voltage input than led forward voltage…
There is no driver, believe me.
I think the closest thing would be a Zener modded 105C but only for closely matched input/output voltages(3S xp/Nichia on 20mm) or mod the light to 3P. There a blank area in the driver spectrum shaped like your description but the size restriction can be worked around with p60 format. Match put a 19mm driver in a AA Minimag.
He simply has to reduce his wishes…after finding what he really wants we can search a driver…
Hah, what we really need is a 141500 battery. That or he should just under drive slightly with 3 AA nimhs.
http://www.lightscastle.com/product/530004
This is 20mm but can be filed down, but it’s 17mm deap and 5 mode though.
Closest Thing I can find.
Matthaus has something cool going on Here if you hadn’t noticed yet.