How many amps will a 15 watt driver put through a single XM-L2 on copper?

How many amps will a 15 watt driver but through a single XM-L2?

OK I got this driver and I don’t know what to do with it. It says it’s for 5xQ5’s and is 15watts. Now cree says 10watts with an XML=1,000 lumens or so. Would 15watts give me 1,500 lumens and therefore be around 7 amps or so? I see the calculation that is something like amps=watts/volts but that doesn’t make any sense at all for this application. So does anyone know if I can run a single XM-L2 on a noctigon with good heatsinking with this driver?

it would likely work terribly for an xml. Most of those are wired for series, so 5x 3volts == 15v. Current at 1 amp would give 15 watts.


That Driver puts out 17.5 Volts

- Output current: 17.5V(800mA) with 5*P4/5*Q5 emitters

- 26mm diameter base, 13mm overall depth

- Voltage: 5V-8.4V

- Mode: High 800mA±20mA; Mid 450mA±20mA, Low 210mA±10mA; Fast Strobe 400mA±20mA; SOS:800mA±20mA

  • Memory: fastter than one second is changing mode; slower than 1~2 seconds is stocking memory

Won’t work…

This is the Driver You Want:

P = A x V

15watts = 4.5 x 3.3

If it's a boost driver, it's a no-go for a single LED. Input voltage must be lower than the output voltage for a boost driver.

That sounds right. How did you work out the math? Any Idea what I could run with it? 3XM-L2’s? 2MT-G2’s?

Must be a boost driver. Is there anything I could use this for that you know of? Or is it only good for underdriving 5 Q5’s?

Thanks I actually do have that driver on the way. Now I’m wondering if there is anything I can do with this one other than tossing it in a drawer or maybe using it as a contact board.

screw a series of cheapo Nichia 119 LEDs to a chunk of aluminium, wire ’em in series and hook the driver up to a decently chunky wall wart of the appropriate voltage. Then hang it above wherever you’re working and you’ll have an awesome work light :slight_smile:

there can never be a part that will be unused, only a part that you haven’t thought how to use yet!

Right on!

This is a buck driver all the way. You should have more cells than LED's for this driver. I know - hhhm, me thinks I went thru 3 already, 3 more laying here. Ohh - also it's the same, exact, I mean specifically, driver as the LCK-LED 5A one, just the LCK-LED has more resistors piled up. So, Hank, I guess in his wisdom, had them change or add more resistors to go from 3.5 to 4.5A, otherwise, same exact driver.

This is the driver I've been using in the Shocker, although, with 3 cells, 3 LED's it goes into direct drive mode, but you still get the 3 modes -- well used to at least...


I think that kind of attitude is why I fear I'll one day end up making a guest appearance on "Hoarders"

it’s a fine line, that’s for sure. Almost everything I hoard comes in useful eventually. This morning, for example, I used some very thing enameled wire that I kept from salvaged laptop batteries to fix the back light cable in my laptop. Saved me $60 right there, though in exchange for a couple of hours very tense scraping and soldering :slight_smile:

the only thing I struggle to use are CW LEDs that I swap out for nicer tints. I usually just give those away.

Dedome them CW’s and you will get more throw and much better tint.

I might try that, but I do like the (slightly) better colour rendering and contrast from NW LEDs.

15 watts boost driver. I’d try it on the 12v MKR with 2 lithiums

your tossing and i just bought some cool white xm-l2 i like lights with maximum lumens

Vinh is getting over 1700 lumens on his 6.5 amps TN31 XM-L2.

I’m not surprised at all. I have a T-90 with a XM-L2 that I am running at 7 amps and it’s amazing how much light it puts out. It took me a bit to get the focus right but man does it throw, it’s de-domed and the reflector is 70mm so the beam it very tight. Just unreal that it can be run with that many amps.

I should add that I am talking about a dedomed XM-L2.

Here’s some lumen numbers from rdrfronty for his vinhnguyen54 modded TN31 de-domed XM-L2 6.5 amps.

Level 1 – .4
Level 2 – 18
Level 3 – 471
Level 4 – 1050
Level 5 – 1515
Level 6 – 1740