I had concerns with how I was connecting to the DMM leads too. That is some beastly output your getting there. You the man.
Hhmm, got to dump some of these crappy parts/tools I have here... I'm so cheap!! But BLF and FastTech made me this way 
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Tom E, maybe a current clamp meter will help.
I don’t think clamp meters can measure DC accurately in this scale.
Their accuracy is often +/- 0.5A (for a Fluke i1010), which I don’t think is enough resolution for measuring emitter current.
I think using thicker home made DMM leads would help.
Or maybe one could short the driver’s output with the DMM to measure the current. If the driver is a reliable true constant current circuit, it should output exactly what it should to the LED.
Not sure about Fluke.
But resolution is not accuracy, I have seen clamp meter has resolution as low as 0.01A, but accuracy wise for example at 7A, is about +/-0.255A.
They are two different things.
Whoops, sorry about that, I didn’t mean to use resolution in place of accuracy.
I guess a clamp meter could be used to measure current but I’m not so familiar with them. 
I just thought of another possible reason for my unexpected low current readings. When I am modding a light, my work bench accumulates debris like shaving of lead, wire insulation, etc. Even a small item getting between the cell holder’s negative contact plate and the flashlights head would restrict current flow.
Just found another Thrunite QC issue. My TN31 is not glued!
I just easily unscrew her stainless steel ring. Good thing is I am ready to mod it. But have to find time to do it.
Well found that also at the bezel, but you need to unscrew the base of the reflector which is blue LockTite, but I did just encounter a new TN31 that had nothing on that thread as well! Also, just did an older model (XML) with the BOA strap wrench's and it came apart real easy, though there was blue LocktTite in the threads.
Thanks for the information. I thought the difficult part is removed. Haven’t tried to unscrew the reflector yet. :bigsmile:
No idea why I didn't think of this.... Probably best way to measure high current at the LED is to solder in your meter leads. Think other guys posted about this. So, when I get a chance, I'll solder my DMM leads maybe to a 18 gauge short wire, then solder that to the LED neg. wire, then do the same for the neg. pad on the star.
For jumping the resistors, I'm now trying this: removed the stock resistors and just solder (connected blobs) to make contact.
I like that DMM idea. You see my post 146. I’m really thinking that may have been my prob. Regardless, I will be trying your idea next time.
Do you think including a short piece of copper wire in the solder blob would increase current too much?
Don't think so... Actually before you posted, I asked a couple of EE's here at work bout using copper wire, or just straight solder - they said should be equal. I'm think'n fried LED's are on the menu... 
I've been using this stuff previously recommended on BLF: http://www.crcindustries.com/ei/product_detail.aspx?id=02005 from HD and seems to work ok for contact surfaces, like the battery carrier and driver contact points. Hard to tell if it made a difference, but doesn't hurt.
Tried this stuff: http://www.idealindustries.com/prodDetail.do?prodId=noalox, also from HD, and seemed to notice poorer performance after it's applied -- yikes, think'n I better stay away from it for now on.
Just ordered a 6ml 100% Deoxit gold pen off of amazon...
If you want to measure in accordance with ANSI/NEMA FL 1 guidelines:
If you’re using “max save” then the max reading needs to be taken inbetween 30 seconds and 2 minutes.
Longer distances are not necessarily better for several reasons. ANSI/NEMA FL 1 has ambient light restrictions and if you go out far enough it’s easy to exceed the maximum allowed. Also, readings at longer distances can be more difficult and prone to error, depending on your equipment, even if ambient light level is acceptable. Finally, it’s not necessary. All you need to do is go out far enough beyond 2m so that your readings converge. In other words, go out far enough so the readings don’t change when you go out farther (+/- the level of accuracy of your meter).
This has been a myth, I believe it is caused by cheap meter many are using as those meter linearity won’t be good. Also the longer distance the larger multiplier, any error of judgement on distance, angle, etc will be magnified and contribute to measurement uncertainty.
Also many like to believe they have best thrower, and when they see larger number, they tend to believe that is the true measurement.
I guess facts are myths. I think you guys are unaware of how many data points have been taken at various distances with many lights, pretty good instruments, and verified against actual OTF rated lights. It's all relative if you consider a $175 meter cheap.
Please. That doesn’t negate any of the facts I pointed out. And if you want to compare I have two Extechs (one of which is $300) and three other meters, a laser range finder accurate to within 1/16-inch, have taken 10s of thousands of readings, and actually own a copy of ANSI/NEMA FL 1. As I said before, some people think they know better than the standard, even though they don’t even know what it is
Thanks for the reply to my question Tom. I’m going to try it to and also use your idea for connecting to the DMM. I think I’m going to run the wires directly to the DMM ports and use something to wedge them snug. This time, I will be inspecting the battery carrier and making sure I have nothing on it to interfere. I guess I should do that first and remeasure my existing set-up before shorting with solder.
Hopefully, I will do it tomorrow night and report back.
I use Noalox to prevent galvanic corrosion between copper and aluminum. I agree with you, it doesn’t seem to enhance the conductivity of the connection. I think I saw somewhere where someone measured it’s resistance and found it was quite high.
Thanks again
I read somewhere it depends on the diameter of the reflector. But I have many big flashlight like TK70, SR95S UT, RC40, they measure about same from 3meter to 6meter, I pick 3 meter most of the time because I can just count on tiles on the floor. After measuring many flashlights, I firmly believe measuring at 10m is asking for trouble because at this distance it is prone to human error by a lot. Try pointing at your meter at 3meter and 10meter, the differences of difficulty at pointing is vast.
I think I have not been clear about my point. Cheap meter is just one of the factor I suspect as we can’t deny the fact many are using cheap meter. Of course some might be using high end meter like luvlites does. Luckily luvlites high end meter shows that it is a myth to measure at longer distance to have better throw number. I believe in luvlites because his equipments and experiences and knowledges in this kind of measurement are far above many of us.