ENEDED

What exactly is the setup for the 5.4A you are getting? Is it a FET DD driver? big wires? Parallel cells providing voltage input?

I have no clue how to get or see over 5A on any XP-G2 so far without going to a buck driver, that's why I'm trying to figure this out. I'm not alone on this. Maybe it's how the reflow is being done?

Typical max amps I get on DD FET setups:

XP-G2: 3.8A - 4.2A

XM-L2 new gen: 5.2A-5.35A

XP-L: maybe little higher than XM-L2 new gen, 6.35A in this BOSS1 is the highest, but no driver

XM-L2 old gen: ~6.5A (XM-L2 T6 4C's seem to get this - could be an old batch)

The best i did with a IOS S4 2b and a FED DD driver was 4.8 amps:a fresh Efest 4200, 18 awg wires and a spring bypass ofc: yet i dont have much exp with this emitter, used only like half a dozen, still got 3-4 pcs in the cache though

Tom, it seems that IOS V6 1A is good too, unfortunately its price isnt, i still dont have KD V6 1A to compare with but the IOS tint is better than U2 1A and 6amps are reachable

Ios V6 1D were great indeed, wonder when shall we have them again

Tom, those numbers are close to what I usually see. Actually yours are a little higher than what I get with the XM-sized dies. I’m really hoping I’ll get this clamp meter and suddenly all my readings will be way higher than I thought this whole time.

I can’t get anything over 4.2amp (3.8-4.0 avg.) either on the S2 2B (5) of them from FT, and (6) that I had laying around and can’t remember what they are any more, running 2’’ 18awg directly to any battery… Imren 26700’s P-Efest 3500 P-Efest 4200 VTC5’s 30Q’s 25R’s Using a Fluke 36 clamp on, Klein clamp on, Klein DMM 10awg Leads? Highest reads are all way’s from the Fluke 36, but Big deal .2? I’m just happy as HELL it’s not only ME!!! :bigsmile:

I have found this vid by Djozz https://www.youtube.com/watch?v=I3oMm-jFSy8 . It shows how the Vf increases with the current. Could it be that xp-g2s at higher amps have too high Vf, thus making it almost impossible to drive them at 5a from 1s? It needs around 4V to run on 5A, which is quite high voltage even for 4p cells (maybe my stupid suggestion again, but what difference would 5p 18650 4,35v cells make???)
could someone measure not only the current, but also the voltage when testing an xp-g2? That should give us some answers

We all know about the higher Vf of XP-G2's, and the 4.35v cells don't do any better - I don't fully understand why, and can't explain it, but in real world tests, they perform relatively miserably compared to high performance 4.20v cells like the 25R, HE2, 30Q, etc., but this is all in one cell applications, never tried in multiple cell parallel setups. I don't think I have that many 4.35v cells to test - maybe I could test with what I have?

Mitko, and maybe couple others, see over 5A on a XP-G2, so the question is what am I doing wrong, or Mitko doing right? From 4.0A to 5.25A or 5.5A is a hugh difference probably due to a big difference in Vf. I'm not set up to measure volts while I measure amps, least not at this time.

Can we solder a simple voltmeter to the emitter wires at mcpcb while measuring current at the tail? Would that voltmeter affect the readings at all?

I was seeing this when I started measuring other peoples builds using the XP-G2’s. Case in point was member D36ME’s TK61 XP-G2 build and quite a few Courui’s built with the XP-G2’s, ( a few Direct drive) I was testing them for LUX on my light meter. Then I started measuring amps, trying to figure out why they were not smoking de-domed XM-L2’s and XP-L’s? So it’s not just my builds but other peoples builds too? :~

That's been my experiences with XP-G2's - disappointments based on relatively low amps, which is why I'm so interested in Mitko's results - he's got high amps and very good throw #'s, consistently no less. What are the possible differences?

  • reflow method: temp and time
  • MCPCB and solder paste used (I've used a variety of MCPCB's with same results, and use a quality Kester solder paste from MtnE - maybe too little, too much?)
  • sourcing: I think the same source, FT, but may be different batch's
  • batteries: think we are effectively the same, hoping same charge level (I'm anywhere between 4.20v and 4.23v
  • driver: I've even eliminated the driver, so unless it boosts voltage, mine should be the same or better
  • meters: think mine does well on high amps, and think my light meter does well (I don't calibrate my meter for throw)

I don’t know, but I remember Vinh went thru way too many (i think over a hundred) XM-L2’s during the TK61vnV4 740kcd ……Nightmare/Adventure!! :bigsmile: I don’t have that kind of intestinal fortitude :bigsmile:

Tom, I’m seeing all of the same numbers (amp reading) that you are, with the exception of my A6. I ordered 2, one had the 1A tint and pulled 6.7A. All of my readings are done with my Fluke clamp meter.

I’ve gotta find one of my XP-G2 mods to double check, I know I build manxbuggy1 an X6 that did 103Kcd from one, but I don’t remember the amperage on it. Seems it was just over 5A.

A member here sent me 2 A6’s to do spring bypasses on not long ago. 2 different tints, both ran 6.18A when I finished. Suprised the heck outta me!

Edit: The only XP-G2 I have left here are all domed and under 4A. Small lights, 14500 and AA.

Hi Tom,

Yes, I'm using a buck driver (FL-2) to get those currents with XP-G2. The driver needs some attention with cooling to sustain operation at that level, though.

I just now hooked up the same XP-G2 S4 used above to an early revision Vishay 70N02 Fet driver with 2 fully charged 25R's in parallel, & measured 4.5Amps, but of course there is some resistance there as I'm using alligator clips to hold the ~10" 18awg jumper wires in place.

Again, the clamp meter should improve accuracy across the board, with everyone's readings, when they are in hand.

In relation to your other thoughts;

Sourcing; I'm not confident that FT has accurate information from their suppliers in regards to high bin numbers, particularly after them advertising "XPL HI V5/V6", & not changing the listing after being pulled up about it here.

Reflow; I'm using a small 'jet' lighter to heat the star (in this case Noctigon) whilst held in the helping hands. I don't use paste - I just dab my solder wire onto the pads & let it pool, then place the led on the molten solder briefly, lift & check that the pads are wet, then place back on & hold down to release any excess solder. I then lower the whole star onto a CPU heat sink to aid in cooling it faster.

Meter; Amp readings - probably the largest variable between everyone at the moment.

I'm reasonably confident in my Luxmeter, as I have been able to compare to a few known factory lights, as well as lights that other members have measured, & been in the same ballpark for throw & lumen readings.

Sorry for getting a little off-topic - I don't even have one of these Boss' yet, lol.

FmC - k, that makes a lot more sense now. LCK-LED has those listed here as FL-215? Think it's the old IOS driver I used in Shockers.

Last night went back and checked my notes - I do have a dedomed XP-G2 S2 2B that hit 5A! I'm like Dale - forgetting more than I can remember. Last night re-measured at 4.95A or so, and it's in a Convoy C8 - I measured 159 kcd taken at 10m with a FET driver, believe copper pill.

Dunno what magic happened with that one though - wish I could reproduce it. Pretty sure it's gas dedomed. Really want to put these under a microscope - want to closely inspect the bond wires... Been hearing that a bond wire can be detached, and just sitting at/near the contact pad - only visible under a microscope.

When’s the group buy gonna start?

In my experience, (making note that I know not what I say) when the meter shows that “-” in front of the amperage number the current is being read in the wrong direction. Changing the position of the wires fixes that and almost always shows a different number, usually lower.

Hhmm, I always set up to read positive amps - thought negative readings were worse. Ohhh!! Also forgot () -- got my UNI-T clamp meter coming in today - in the local Post Office this morn - ordered out of US warehouse from TomTop.com, pretty good price - $33.85 shipped w/tracking, ordered Jan 6th.

TomTop is one of those familiar look'n sites - seems to have a lot in common with BangGood, both started biz in 2004, but seem quite different in policies. Could just be sharing the same storefront web tools or web services.

Also, lumens/throw measurements seem to track well with my tail amp readings, so I think I'm in the ballpark - for high amps, I've seen gains of 0.1A - 0.2A by cleaning up contacts with the DMM leads and cells (using a little bit of NO-OX-ID helps at times).

I read from the negative when testing at the emitter to prevent a short if something slips or otherwise accidentally makes contact, but that’s not what I was referring to.

Reading the current backwards shows a negative reading on the meter, reversing the position of the probes removes that minus sign and gives a different reading. I don’t know electronics, so I don’t know what it means EXACTLY, but it’s about direction of flow I think. The clamp meter reads from positive on the face of the meter to negative away from the meter or the back side. Since it’s designated on the meter, I assume it matters.

Edit: That’s why I said anything, hoping someone could explain it. When I see a reading like that –5.41A above, in my own experience if I switch positions of the leads to get rid of the negative symbol the amperage will be lower. I don’t wish to report a higher reading in error, I fall under enough scrutiny as it is.

EditII: Testing a Courui L2 with XM-L2 emitter and Efest 3500mAh 26650 I get 4.84A if the facing wire is on the rim of the light and the backside wire is on the neg end of the cell. Reversing positions and getting the negative symbol, I only get 3.95A. So, it matters. Why, I do not know.

Hhmm, assume you mean Convoy L2, not COURUI L2 - I don't think I ever saw a difference that large, but not sure - I never look for it because as soon as I see the negative sign, I reverse the leads, so I only read and record positive amp #'s. I'm talking about using a regular UNI-T DMM, not a clamp meter.

Also wait'n on freeme for the group buy - see here: https://budgetlightforum.com/t/-/35973. Nothing new posted, but freeme posted he's getting a bit burnt out on these, I'm sure some frustrations...

Herewith 2 recent builds I did with dedomed XP-G2 S4 2Bs from IOS…

4.7 Amps - Jacob A60 Build
5.1 Amps - Convoy S2 Build

Both measured with my Fluke 376 True RMS AC/DC Clamp Meter