Need help choosing led driver

[the crow]

Hello all i need help choosing led driver for this led (SFH 4715S) my host runs off 2 x 18650 batteries
http://catalog.osram-os.com/catalogue/catalogue.do?favOid=0000000700019a0200d70023&act=showBookmark
This is the data sheet for the led http://docs-europe.electrocomponents.com/webdocs/1121/0900766b81121e5e.pdf
Im goning to buy the host off dx so if possible i could buy led driver off them.Can i link you to the torch because the driver in it might work with the led ?
Hope these links are ok? Please remove if not.

thanks the crow

 

[RoGuE_StreaK]

Just post up the torch's SKU or title description, that way you can't get into trouble for linking to DX; people can just search for it to check it out.

From what I can gather, you need to be looking for a max drive current of 1Amp at 3.4V. So roughly 3Watt, depending on how the driver is listed.

Will you be running the dual 18650's in series or in parallel? Each has it's pros and cons, eg. series would mean you don't need a boost circuit as combined batteries wouldn't get below 3.4V, but also means a lot higher initial overhead voltage to get rid of, usually just by wasting as heat. Parallel means less overhead initial voltage, but also means you start to see dimming below 3.4V unless you have a boost circuit. 3.4V is a little high for a li-ion cutoff, would be nicer to be able to run it down to 3.2V or even 3.0V (3.2V is apparently a bit better for battery longevity). Also parallel is considered "safer", less chance of :poof: from unbalanced cells.

Also need to know how much space is available for the driver, as there's lots of different diameter ones.

Do you need modes (high, mid, low, strobe etc) or just fully on / fully off?

After a brief browse of DX I was going to suggest SKU 107676 (5-Mode 1000mA LED Driver Circuit Board for Flashlight (16.8mm - Diameter / DC 3.0~9.0V)) but its only review indicated that it didn't in fact go down to 3.0V as advertised (ie. implied it was a buck/boost driver, but didn't appear to boost)

No more looking for me, I'm off to bed.

:welcome:

 

[the crow]

Cheers for the welcome bud.Im in the uk so i cant reply right away most of the times.

The torch im gonna try is this one cheap but ok to start with i think SKU: 117761.
The batteries are in series.

I picked this torch for my gun, to fit on the top of the scope.

I need bif 50+mm head for aspheric lens.I cant realy tell you how much space is their has i havnt got the torch yet.

I could get driver off other site if they dont do any on dx.

I would just like fully on / fully off but i cam manage with any mode.

thanks for tryin to help out
the crow

 

[RoGuE_StreaK]

Looks like that torch's driver is regulated to 1Amp, so should be fine, at least as a starting point. May possibly not get the best life out of your batteries (not much info on what it's range is), but should do the job without having to mess around with installing a new driver.

Hmmm, gun + scope + IR Thrower... remind me to stay well away! :eek:

 

[the crow]

Thanks for the info ill just get the torch.
thanks the crow

 

[syti]

Hi guys. I have the same problem the crow
I have OSRAM black 940nm emitter(3.4V max, 1000mA max). Can I use my UF wf-502B 3w tourch? It has 1A Current and 4.2V working voltage.
I dont wanna kill my Osram diode.
What driver do you suggest?