Okay. So if I’m getting .56A at the tail = 1.1A …and 0.5A to each emitter, that’s a lot of resistance. I’m not used to encountering resistance like that. The emitter wires are very thin, maybe even 30AWG that have 28AWG going to the driver, where they are spliced onto 26/24AWG. It’s still a big drop in current though. Who makes a large driver like this one that puts out such insipid current. Could it be possible that this driver was meant for to run optimally with higher voltage than 2 x 18650?
Everything is normal.
You always have to think on the power so voltage times amperage.
input and output power are always the same with 100%efficiency.(in real world less)
Eg.1
Two cell single emitter light:
Input measurements: 2*4V*1.5A=12W.
Emittermeasurements: 3.3V*3A=10W
Your workaround works 2*1.5A because the battery voltage of one cell is near the LED voltage. Calculation from tailcap current could be 12W and 80% eficiency 12*0.8=9.6W
EG2:
Two cell triple emitter in series.
2*0.56A*4V=4.5W. Emitter: 3*3V*0.5A=4.5W
Your workaround doesn’t work because one cell voltage is way different from LEDs voltage…
Calculation based on power works…
So the best is always to check the power. 4W power for 3XMLs which are rated for 10W each makes a bad light….
You have to consider the voltage sag of the batteries when doing, too.
One question I have to ask: you have checked in high mode, right? 
High mode is the first thing I check. It’s my main concern. Even without a DMM, you can see this light is sadly lacking.
I’m having issues with something very similar to this driver (maybe identical?) in a Skyray STL-V2 (single XM-L2). The label on the driver boards are: HX-1170A ( first layer / contact board) and HX-1170B (board with inductor).
The issue I am getting is the board appears to have 2 different mode groups… one with a full 1.7 amps on high and the other only drawing 0.5 amps on high (both at the tailcap), on high at 0.5 amps I am reading a voltage drop of 2.8V across the LED. I have taped any points on the driver that look like they may be touching something they shouldn’t be… still no joy, nor can I figure out if these is some combination of switching between modes that does it. If it makes a difference the LED is an XM-L2 U2 on copper.
I am tempted to put this down as some sort of contact issue but the current draw is always around 0.5 amps regardless of which cells I use… I wonder if this driver is designed to work as both a single XML or triple XML driver?
Is the single emitter version not called STL v6?
Some versions of this light had two mode groups which could be selected through tightening the tail in the head…
I just checked my archive with pictures of my STL v6 driver pics and they look similiar.
I have not measured emitter current but it was more than 4W(have wrote it down in scares thread). I checked last week if the stock driver can drive two XML in series because I plan to use it for a mtg…it worked.
mY STL v6 pictures:
Current sensing resistor is under the coil.
Quite frankly, I can’t even remember putting this light in my shopping cart. I think I had seen good reviews and some youtube vids that made it appealing. I believe these all had superior current readings. I guess FandyFire started employing different drivers for more profit per unit.
I just did a little web search to various sites and found these specs that are not listed on FastTech.
Voltage Input: 3.2~8.4V
Circuitry (mA): 1000
So, it looks like it really is supposed to be a 1A driver after all. How very sad.
have you got one of these to try out?
http://intl-outdoor.com/boostbuck-318v-triple-xml-circuit-board-p-542.html
I personally never had the feeling that people were amazed by this light, all happy guys have the 3T6 which is superb even if there are different version now out there.
And it is still a 0.5A driver, even if you still doubt it….
It needs to be modded anyway. Peel the black blob and let’s see what is underneath.
Have you measured the driver cavity?
Is there space for 26mm wide and 25mm high driver?
I’d say the driver is not doing it’s job, but is direct driving those leds. At 500mA Vf of each led would be around 2.8V or maybe even less, so that makes around 8.4V for three in series. The difference in current reanding appears because of the drivers resistance or maybe even some voltage drop over a semiconductor on that PCB. Wire those two cells in series and hook them to the leds and read the voltage drop over the leds and current draw and you’ll get a bit clearer picture of what is going on there.
I’ve been looking at that one Gords. I thought I had grabbed one on spec in my last order that’s in the mail, but it was the 4.5A buck driver. It’s dimentions are perfect too. I wish it didn’t take so damn long to recieve an IOS order.
I have these two drivers in the mail also. I ordered them for no particular reason.
http://www.lightmalls.com/8-4v-3000mah-5-mode-led-flashlight-circuit-board-led-flashlight-driver-for-3xcree-xm-l-t6-or-5xcree-xm-l-t6
http://www.lightmalls.com/17mm-3xcree-xm-l-t6-emitter-led-driver-led-circuit-board-2-18650-8-4v-2500mah
I’m in no rush. I have lots of projects pending.
With 2 x 18650 and triple emitters, you’re kind of in the no-mans land of buck or boost or both.
All of the lights I’ve worked on so far have been torches I’ve liked, and modded them for love. This one I’ll be modding out of sheer hatred.
It sounds like you have something in mind Werner.
I decided to open up the LED holes in the reflector. I didn’t like the way it sat on top of the emitters plinth. I wanted to open it up enough to surround the whole base and rest on a centering ring. I felt the way it was now was affecting the focus of the emitter.
As I was grinding it with my multi tool, I noticed it rippling, as if a layer of chrome was starting to peel off. I looked closely, and realized that there was a sort of foil disc taped to the bottom. After I peeled it off, the original holes were exactly how I wanted them.
That are the dimensions from the old school 3T6 driver. This one is made for parallel LEDs and one of my favorites.
The ones you have pending look promising, the informations are a bit small on light malls. Please report your results.
I think werner is thinking of the tr 3t6 driver from manafont, it can be resistor modded satisfactorily I believe.
too bad it wont take three cells, the dry driver is the obvious choice
edit, werner beat me to it lol
I know, I have three of them sitting in front of me.
18350 imrs and a spacer?
I think as soon as you went into DD, 18350s would bottom out.
Did you get my PM?
Does yours have the spring up against the driver? Its designed to be 2 group, one when its tight, one when its loose. Theres is 2 ground rings on the lower board?
Chris
mine does 1.7 at the tail
Werner. I tried to reveal the driver, but it doesn’t want to be exposed for what it is. The cap peeled off easy enough, but the rest seems fused to the components. I picked away at it with tweezers, but I finally had to give up.
Thar driver you like should fit easily. I checked it out at Manafont, and they don’t give any current rating.