Looking for driver for 1st high power light

Hi, I have a couple 10W LEDs to play with. I'd really like to use them in a case I have that fits a 3.6v li-ion battery. I've seen the LEDs demoed at 12v with a good heatsink, so I'd like a driver that can get me at least 10v from the 3.6 source. However, I'm new to shopping for such things, and so far I don't have remarkable confidence in anything I've found. Does anyone have a good driver they can recommend?

Thanks for the help.

Welcome to CPF!

What kind of 10 watt LED are you using? 12 volts to a single LED must have been with a buck regulator in the circuit, correct? A few more details about what you have and what you have in mind to do will get some helpful hints. A Cree XM-L 10 watt for example has a forward voltage low enough it works well with a linear regulator on a single Li-Ion. It says 6 volts max. But really that's too much heat. A single Li-Ion or 3*NiMH works great with an XM-L and that regulator.

The SST-50 is almost 20 watts. But the higher Vf means a single Li-Ion, between the battery voltage under load and a regulator's drop out voltage, doesn't have enough power to drive the LED to full power. Well maybe for the first 10% of the battery charge. Something like a TaskLED H6CC or H6Flex or a Der Wichtel 5 amp would be required for an SST-50. Neither of those works with a single Li-Ion though.

I'm not sure what kind it is. But after looking over the Commonly Used LED Emitter Index thread, it looks closest to a large version of the Golden Dragon. Without the red diode though.

That's going to make things a little difficult if you don't know for sure what type of LED it is. Do you still have an invoice from the place you purchased them? If you're pretty sure it's one of the Dragons, you can download the data sheets from the Osram site to find one that looks similar. Perhaps if you post a picture of it here, someone can ID the thing. The only thing you really need to know is the maximum current the LED can handle before you buy the regulator. AFAIK, Dragons range from 400 ma to 2,000 ma max current.

Ah, just found it online. It's this LED

Which, according to the comments, can be reasonably powered by 12v at 700mA.
There's a datasheet link here.

So am I nuts to try to power this from 3.6v? Does that mean it's really impossible?

Thanks for your help so far.

You need a boost regulator. The Flashlight Electronics - Batteries Included forum has a link in the Threads of Interest sticky called Driver board list/regulator board list. The two best that come to mind are the Shark and the MaxFlex. The pdf you linked to says a typical LED is 10 volts @ 1 amp for 650 lumens cool or 600 lumens for warm. So going by voltage ratios and assuming 90% efficiency, you need to draw just over 3 amps to get a 1 amp output @ 10 volts. That's pretty close to the limit for either of these boost regulators with a single Li-Ion. But at the 700 ma value you mentioned it should be OK. Either regulator would have to be mounted with thermal compound to dissipate the heat.

FWIW, I know you said you already have a few LED's. But for less than the price of either a MaxFlex or a Shark, you could buy a Cree XM-L and a 3 level linear regulator. The regulator Craig is selling is basically the same as the one Download or ShiningBeam sells. It would easily run off a single 18650. The T6 bin @ 2.8 amps has an output range of ≈ 870-930 lumens. It's much brighter than the DX LED.

Thanks Al. That's exactly what I needed to hear. The Cree XM-L sounds like the smarter, and much more impressive, way to go. I think I'll keep the DX LEDs around until I get a project that has a 12v system to begin with.

Glad to be of some help.