Ok - vinh removes the resistors, direct wires the connections instead for both the TN31's and K40's. That explains a lot to get 6.5A. Interesting that the lights don't poof by smoking components, but he's done a ton of these lights, maybe only recently with this resistor mod though... Hhhmmm, should I try it??
For measuring throw, rdrfronty has a done a great deal with that, many distances, many lights. I'm pretty sure he stated 15 meters as ideal, anymore than that doesn't seem to make a difference. For under 15 meters, basically the closer you are, the lower the #s because of focus, but I'm sure depends on the beam pattern too.
Direct wire makes sense. I was getting so frustrated trying to get higher current that I ended up added one R030 and two or three R100 resisters on top of the stock resistors. I should have been getting close to 13 amps at the emitter (wasn’t going for that, just wanted to get up to 7ish), but was measuring 5.x amps. Don’t recall the exact current I got. I didn’t like the way I was connecting to the meter either. It was not a good day to be moding a light like that. I can say with confidence I was not getting over 6 amps.
I assume he is using wire that provides almost no resistance. I saw some discussion in the German thread about that. I think the poster said the wire got pretty hot, but he may have been using wire designed to provide measured resistance. I need to find that thread. I remember it was a bit vague though. The Google translation makes it even more hard to follow.
Thanks for the input on the lux testing Tom. I’ll post here next time I go in to the light.
Generally 10m is the point that most serious throwing lights I tested started getting their peak numbers at. 5m works for 90% of the throwing lights too. But a few still readily slightly low at that distance. I generally just go with a longer distance to be safe, usually at 15-25M. If you don’t have help like I do with my brother or have a good max save on your meter, just try to get the longest distance over 5m that you can still read the numbers. Now of course I’m talking throwers, meaning a light over 50K. Not sure if my Preon 0 would even register on my meter at 5m
My rule of thumb is - When in doubt, increase your distance. You never have to worry about going too long a distance. It’s surprising just how far you can get true readings on a lights throw.
So dividing the constant 0.1435 by the total resistance to get the current to the LED is just a theory but not quite accurate in reality? :~
If TomE’s adding of 2 R082s gets 5.2 Amps to the LED when using the theory above it should get 6.685 Amps (i.e. the actual is 77.786088% of the theoretical value) then adding a third R082 in parallel should have a theoretical current to the LED of 8.435 Amps or an actual current of 6.56 Amps to the LED.
So, think I reproduced vinh's #'s - yes, he's not crazy, and yes the #'s I believe are real.
All modes work fine, it appears. This is a 2012 XML U2 model. The tint looks great, actually maybe too white - I was getting used to the yellow tint. Ok, got another to do asap. I can easily measure carrier amps, will post soon.
I don’t want to derail the thread, but I have a thought about that kapton tape underneath the copper.
May it be there to prevent the galvanic corrosion of the aluminum in presence of the copper? I know from electrical equipment that these two materials musn’t be connected together, because of the galvanic incompatibility which may cause the aluminum to be corroded by the contact with the copper. An intermediate piece compatible with both materials must be put amid them.
I think these effects are faster in connections under voltage, but can also be present without electricity,just with the presence of an electrolyte, which could be moisture ( and I am trying to recall all this data, if everything is wrong feel free to correct me)
OR maybe they just forgot to remove the protection tape… This seems more plausible coming from the Far East
2nd TN31 measured 461 kcd throw at 4.3 meters, slightly better, effectively the same. I measured amps at the carrier on #1 and it was 3.48A -- ouch, 10.46A effective -- holy crap!
I’m no electronic expert, but I imagine that the theory is valid within a certain range. Beyond that range, the limits of certain components start to interfere and thus limit current. Additionally, the xml2 requires more voltage than the xml. That too may be factor.
Actually I snipped off old leads from an old style resistor, so it's fairly thin stiff wire - wasn't too concerned about thickness there - hope it's ok.
Ya, some buck circuits do have max current limit feature. Looks like shorting those resistors just make the circuit pushing at maximum current. Well I am guessing here and I have not studied the circuit. Wonder need to cool down the circuit with heatsink or not.
That’s a good point DENGOH. The driver board in the TN31 is substantial and appears to be well connected heat sink wise. It has a nice ledge and screwed down with protective plate that may also disperse some of the heat too. Looks like it might be adequate stock.
