Would using two or three batteries make any difference with the R100 modification?
Post #425 here: https://budgetlightforum.com/t/-/27963 -- after adding an R100, I measured 4.6A at the tail for an MT-G2 modded Y3, so, maybe does make a difference? Weird... Sorry, wish I had time to test on a XM-L2 Y3...
Anyone used one of the 26mm maxtoch mcpcbs? Is it an easy replacement?
I have not put my light together with one. The maxtoch mcpcb is 0,5mm thinner compared to stock. Not sure if that makes a difference. The place you solder the wires does not touch the reflector, so that is good. If you want to use thick wires you might want to do some very minor trimming to the mcpcb were the wires come through.
I plan to, but haven't even taken mine apart yet. I just realized that the reflector is so loose it literally rotates when I lightly flick the flashlight (I can hear it spinning). Need to work on raising the entire shelf before fitting the MaxToch mcpcb. Other than the height issue, the diameter seems to be a direct swap. Someone correct me if I'm wrong.
Ummm - 3 things with the LED/MCPCB <-> reflector height:
- stock it's not tight, apparently (don't think my original WallBuys unit had this?)
- replacing or sanding down the LED alignment piece will cause more loss of height
- replacing the MCPCB will cause more loss of height
So, you need to take all 3 issues into account for planning a height boost 
. Don't forget possible lens replacement, maybe different thickness...
^ Thanks for pointing out the lens thickness. I got the AR lens from CNQG. I haven't compared the thickness, but it's probably thinner than stock and loosened things up in my unit.
I initially looked around for a replacement o-ring, but I wasn't able to find anything in the budget-friendly realm.
I took apart my MT-G2 modded Y3 that has the R100 added (removed the MT-G2), and measured 3.55A to 3.60A with an XM-L2 and one EVVA 26650 unprotected cell. I then put in a fresh Efest 35A 186650 and measured just over 4.0A. So, I can't explain the results you got. I would highly suspect your DMM - are you using the stock leads? I use 14 AWG custom wire leads and need them to measure high amps. Please post any updates and details on your DMM and DMM wires.
This is the DMM I’m using. Been measuring driver currents up to 4.5A reliably for the last 6 mo. It’s not modified - haven’t built any lights drawing more than 6ish amps, so figured I’d get around to beefing it up with thicker leads when my flashaholism guided me to more power.
It is possible that I could have fried the R150 when I added the R100 on top of it, I suppose. But wouldn’t the current have gone down before/after if that were the case?
Y3 #1 - Stock driver, stock driver spring, dedomed stock LED on stock mcpcb, one fresh EVVA 26650 (unprotected): 2.25-2.30A
Y3 #2 - R100 added over R150, stock driver spring, stock LED, 22ga LED leads, one fresh EVVA 26650 (unprotected): 2.60-2.65A
Both Y3’s from the cnqualitygoods GB.
And for reference…
Convoy S2+ - 3.04A Qlite flashed with NLITE (8x7135’s), stock springs, solid copper spacer soldered to brass pill, 3-up dedomed XP-L V5 2As on noctigon, 22ga LED leads, fresh NCR18650PF (protected): 3.05-3.10A
I was beginning to think it was a faulty DMM for sure… now I have no idea what to think. Could there be THAT much resistance in the driver spring or did I draw two unlucky straws with the drivers in my Y3’s?
It could well be the battery not able to deliver the current required. I received two brand name 26650s awhile ago and one of the batteries performs poorly in current tests but has the correct capacity under light loads. The other battery in comparison performs as expected.
The AR from the CNQG BG is indeed thinner — mine rattles while the regular glass lens does not. Anyone know if the maxtoch mcpcbs are thicker than the standard mcpcb? It would sure be mighty helpful if they are. Otherwise I guess I’ll either shim or find a thicker o-ring somewhere.
Both came from MTN. That would be a really huge bummer, but it would explain a lower-current-than-expected problem I’m having with an Ultrafire F13 I modded with the 22mm 16x7135 linear driver. Can’t remember exactly what I measured it at… but I think it was in the 3-4A range. I figured the DMM was acting up - got pretty hot on high.
Edit - I’ll test the Y3’s with a pair of unprotected NCR18650PFs in the morning. If I can make it that long — awfully tempted to get out of bed to see if that’s the issue. Gonna suck if the $35+ I spent on 3 of those 26650’s was wasted.
Wow - never saw a stock DMM measure high amps, like over 3A reliably, even a Fluke, but you may have a winner there but I definitely would not trust that setup for regular use. I've seen this before - guys thinking their stock leads work ok, and once they get heavy leads, their eyes open. If they are really good (doubtful), then could be other things as mentioned - cell, bad resistor, etc., or something different about your driver vs. mine. A light meter is always a nice way to verify things to see relative effects.
There are multiple EVVA unprotected 26650 Mtn sells - which exact one? If it's the 5200, it's pretty low performing compared to the re-labeled KK 4000. I'm staying away from those 5200's. The 26700 cell is even higher capacity and high performing (mine measured at 5300-5400+) - win/win, and fits the Y3's that I have.
I measured the CNQ AR vs. stock lens last night - AR is slightly less in diameter, maybe by .05 mm, close...
Definitely DMM stock leads are the problem.
Dunno - I'm not saying it's impossible that DMM w/leads would work well, just very hard to believe. Thought we've been down this road many times before, and it always (like 100% of the time) ends to find out the stock DMM leads are N.G. - may seem to work on some setups/lights, but not all - after many posts back and forth and time spent, turns out to be poor high resistance leads...
Again, I got 3 DMM's including a Fluke, and all stock leads and extra leads I've bought fail to measure high amps reliably.
Ohhh - also, it's important what high amp setup youv'e been measuring ok in the past. if it's more than one cell in series, totally different animal. If you say voltage was in the range of 3.0 - 4.0, then that's different.
grantman321 wrote:
Y3 #1 – Stock driver, stock driver spring, dedomed stock LED on stock mcpcb, one fresh EVVA 26650 (unprotected): 2.25-2.30A
Y3 #2 – R100 added over R150, stock driver spring, stock LED, 22ga LED leads, one fresh EVVA 26650 (unprotected): 2.60-2.65A
Both Y3’s from the cnqualitygoods GB.
And for reference…
Convoy S2+ – 3.04A Qlite flashed with NLITE (8×7135’s), stock springs, solid copper spacer soldered to brass pill, 3-up dedomed XP-L V5 2As on noctigon, 22ga LED leads, fresh NCR18650PF (protected): 3.05-3.10A
I was beginning to think it was a faulty DMM for sure… now I have no idea what to think. Could there be THAT much resistance in the driver spring or did I draw two unlucky straws with the drivers in my Y3’s?
Hi grantman321. I'm assuming those are tailcap measurements and that the Y3 driver is a buck driver. It's pretty normal for buck drivers to deliver less current with one cell. I think it's because they typically require more overhead voltage (Vdo). So less voltage is available to drive the emitter and therefore the emitters allows less current to flow. Buck drivers work best with 2 or more cells in series.
I don't have time to read all the Y3 threads. Has anyone else reported tail current on 1 cell with the stock driver?
Well, I tested the lights over again with unprotected NCR18650PFs and got similar results - and then again with another unprotected EVVA 5200mAh 26650 that I ordered separately from the first two. Still getting roughly the same results for each light with a variation of about +/- 200mA between different batteries.
I’m not arguing at all that my DMM leads aren’t the issue — I assumed when I bought a $20 DMM that it wouldn’t be perfectly accurate and reliable out of the box — accurate enough for rough estimates when testing mods was all I was shooting for there.
So as of now, I have no reason to believe the batteries are the issue — gotta be either the DMM or something screwy with the drivers in the Y3’s I got. Still not quite understanding how it could measure some single-cell lights with relatively accurate results and others way off from expected. All of the batteries tested were between 4.10 and 4.18V resting, and all tested in the same manner, with the amps I reported being a rough estimate of the average after it settles down over a few seconds.
I don’t think I’ve ever actually tested a multiple cell light with this DMM before. I only have one two cell light that I use regularly (a modified Convoy C8 with a zener’d Qlite +4x7135s), and I know roughly what the current on that light ought to be, and the light works great so I’ve never even bothered to test it.
Bottom line… I need to figure out how to get this DMM set up right and then go from there. Are there any writeups on BLF about modifying budget DMMs for better accuracy?
The leads have resistance and resistance cause a voltage drop if you measure current. This dropped voltage is “stolen” and less voltage gives different current.
How the lower voltage behave on a driver depends on the driver.
The stock y3 behaves like that:
4.2V gives 2.3A
4V gives 2.4A
3.8 gives 2.6A
3.5V gives 2A
It’s regulated to some point(around3.7V) and after that power drops.
I just plugged it to a power supply and noted the display current and voltage which is not absolute accurate but enough to enlighten all the differences in tail amps a bit.
I bought 14 AWG silicone multi-strand high temp wire and directly soldered them into bare DMM connectors. On the other ends, I strip off bout 1/2 inch then solder the exposed ends up so it's stiff and chunky. The 14 AWG silicone is 12" long, nice and flexible, easy to work with, but not too long - again, longer it is the more the resistance. I bought the wire here: http://www.buddyrc.com/black-14awg-silicone-wire.html and red, cheap, good quality -- probably best deal around actually on wire at BuddyRC.
For the connectors, dunno - I got mine @work, but you could buy a spare set of leads cheap ($3 - $7 eBay, FastTech, etc.) and cut off the wires.
This is a sweet cheap DMM I have: http://www.fasttech.com/products/0/10002748/1483104-uni-t-ut33d-1-9-lcd-palm-size-digital-multimeter, but I leave it on and kill the battery all the time. So I bought this one: http://www.fasttech.com/products/1004/10002748/1204400 with a battery saver, and 20A capable 
.