Care to share any thoughts on this issue based on your modding experience with the A60? You did add a 2.8A Nanjg to an A60, right? Did you ever check current on direct drive with the A60? Comparable to gords?
-Garry
AMC7135s regulate current by dropping a sufficient voltage from battery to the load — Much like a variable resistor. Direct drive will always be higher because a 7135 has the mentioned small voltage insertion loss. The trick for efficient 7135 operation is to have a minimal difference between the battery and load voltage at the current operating level, and a flat battery voltage discharge curve so that the 7135 can stay in current regulation as the battery discharges.
Think of these chips as linear buck regulators. No PWM and no boost in the 7135 itself. However the current can be chopped using PWM to get the lower light levels like low, medium, and the strobes that everyone here so desires…
You know, I'm pretty sure I measured like 2.8A with that setup but saw no increase in lumens/throw which didn't jive with what people stated, about the circuit only allowing what the LED wants to take, so in that setup you'd expect to measure 2.3A for example if that's what the XR-E would take at the max.
Oh - that A60 setup doesn't exist anymore, now it's still2.8A, but an XP-E2/SinkPAD doing 106 kcd or so...
Do you know of any?
I have the driver that came with the popular high output Ultrafire Manafont drop in. I always considered it DD. But the other day I found out the output current was not that impressive. Tested it today. 7,5A input, around 5,3A output (rough numbers) It will probably overheat in no time… The stock driver spring melted in seconds btw… J) 0:)
I have been waiting 40+ days for a supposedly DD east 092 from Fasttech… Mail or something messed up… It may arrive tomorrow or in a month…
My first east 092 was not DD on high.
I always like your thinking Scaru… “More is more, and more is better” pretty much sums it up it seems…
_
Thanks to everybody for the links and info (so far)! 
So you’re saying that the linear drivers shouldn’t provide more current than direct drive?
I saw 3.26a direct drive on an a60….
I pooped my pants and reduced the wire size to give a much more sensible 2.8a :bigsmile:
as far as I’m aware, emitters will draw whatever you permit them to draw, you limit current by “designing in” currently bottle necks, that’s why its a bad idea to deoxit all the contacts and threads then wire the tail spring on an hd2010, your removing the current limiters.
Agree on a stock HD2010 direct drive setup, but I did a few XM-L2/SinkPAD 2010's and gotta get rid of all that resistance. The new KK ICR 4200's do pretty nice, as well as the MNKE IMR. I measured one 2010 after the mods, and was like what? This is disappointing, then ooops, forgot to wire the tailcap spring, so tested in the lightbox by jumping the batt neg to the body, and wow - 170 lumens added! Wired the spring with the solder wick down the middle, tested again -- all 170 lumens came back, interesting to see the direct result...
I = V / R
Which ever has the lowest resistance will win. The winner should be direct drive, the amc7135 drops .12v. The battery voltage would stay the same as long as the load was the same, if the current increased the voltage would drop more from the battery but the resistance in the circuit would have had to decrease for that to happen.
If using a direct drive driver then it has to have a voltage drop off less than .12v or the amc7135 driver will beat it using the same setup.
hahah!
Great one! 
Everybody is missing the fact that the higher drive current here was done with LiMn battery and the direct drive was with Li-on. The Li-on most likely had a much higher internal resistance and could only deliver 5 amps. Direct drive with the same LiMn battery setup and I would expect to see more than the regulated 9.16A.
That actually might be the case.
Sorry if I confused everyone. I knew I was missing something.
So to recap, it’s not possible to increase the current with a linear driver compared to a direct drive setup, right? 8)
You could think of scenarios where there wouldn’t be a difference, but as a general rule, all else being equal, direct drive should deliver more current.
+1
Yes, AMC7135 chips do not ‘PUSH’ current through anything. They can limit it, but not create it.
Picture an AMC7135 (or multiple of them) as a water valve. The valve doesn’t ‘push’ water through the pipe, but it can regulate it. If 10 Gallons per minute flowed through the pipe without the valve, you won’t magically get 12 gallons per minute with the valve, but it does allow you to regulate from 10 down to zero. In reality, there is some resistance to the valve (just like in the AMC7135’s) so that actual values will be from less than 10 down to zero.
PPtk
I found this thread while trying to figure out what to do to drive a triple XP-G2. I’ve been using a 105C with 4 add’l 7135s, but was curious what more I could do.
So, tonight, as a test, I hooked up just the triple with a new Panasonic PD battery, and used a clamp meter to measure current to the emitters.
I just left it on for a few seconds, but I got ~7.98 AMPS.
I’d like to have modes, so I was wondering if there is any 17mm driver that would be able to put out that kind of current?
Add more amc7135’s. You may not reach the direct drive current but shouldn’t be to far behind.
You also have to remember that the battery can not stay at that voltage very long. So the amc7135 driver may fall out of regulation pretty quickly becoming direct drive. It would only regulate the current until the battery’s voltage (along with voltage sag and other parasitic losses) reached the vf of the led at a specific current. Using 6 amps as a example.
If you look at Djozz graph you can see at 6 amps the voltage needed to achieve that current would have to be some where in the 4v range after the other losses like voltage sag and other parasitic resistance. So if you added enough amc7135’s to give you 6 amps out to the led, the time it would stay at 6 amps would be pretty short considering the battery at 4.2v before any losses or voltage sag where factored in. Probably less than a minute, just a guess. Once battery voltage falls below 4v the driver becomes direct drive (Useless besides having modes). What ever the voltage the battery is maintaining (the blue line) will be what the led is seeing in current (at the bottom of the graph) in Djozz graph. If you look to the graph again you can see that once the battery voltage has fallen to about 3.5v (blue line) the led is only see about 2.5 amps (bottom numbers). Looking at a NCR18650PD graph looks like if you set the drive current with the correct amount of 7135’s to about 3 amps it would stay in regulation about half the run time, the other half direct drive at what ever the current it can push for the falling voltage. Hope I made some sense.
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Hope you are use a good heat sink with copper behind the led or she may not last long at 7.98 amps.
If you want to push a led at high currents and stay in regulation a buck driver is more suitable for the purpose.
Unfortunately, I don’t know of one that has a 17mm diameter putting out much over 3 amps.
You’ve kind of struck on the conundrum:
Understanding that they can go above that, the XP-G2s’ specs say 1500 mA MAX, which, since the star I have is parallel, means that I need 4.5 amps just to get the XP-G2s to the “book” maximum. However, with a single 18650, it doesn’t seem like it’s possible to get the XP-G2s to that point in the current vs. voltage curve, since I don’t think an 18650 will output 4.2V under load.
So, it seems like the only way to get a true 4.5 amps to the emitters is a “real” direct drive, and a good (but not too) good battery.
On the other hand, I do want modes, so that I can run the light at “sane” levels most of the time, and use it in high mode just for brief periods, on occasion, which implies using a driver.
Having said that, I just re-built the light with direct-drive, just to see how it’d do. I kind of “chickened out” and used 26AWG wire. With that, I am measuring 5 amps tailcap current (which emitter current) with the PD battery.
It get hot, really fast, but it’s pretty bright :)!
I just now caught the part about you using this on a triple xp-g2. 
That makes more sense then, thought you where using a single led.
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You could still use a amc7135 for modes but it wouldn’t really be doing anything besides modes if its set high enough. I would think if you used a amc7135 driver set to above 5 amps and used thick guage short wire every where and maybe spring resistance mods that 5 amps would be feasible. I’m pretty sure the PD will handle the load. In Djozz graph you would need 3.4v to make 2 amps to each emitter but the battery would see a 6 amp load which it looks like it could handle.
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Didn’t know if you had seen this or not.
I decided that, while it was cool (or hot) having a 1-mode 3up drawing 5 amps, it wasn’t practical, so I went back to an AMC7135-based driver, with 12 380mA 7135s (original driver is the 3.04 amp one from IS + 4 380 mA 7135s I added).
I didn’t change the original leads, which are 26AWG, I think, and I didn’t add braid to the springs (neither + nor - springs), and measuring tailcap of almost exactly 4 amps (no tailcap switch) with a fully-charged PD battery.
Just a point of info…