What I am wondering, in terms of efficiency, and max output how would people rate a typical nanjg 105C type driver with a very high amount of AMC7135 regulators vs direct drive?
This is just fiction. But if you have a setup that will deliver say 7A in direct drive (without a driver). Would a 21x 7135 driver (7350mA total) deliver around the same current (7A), or would it be considerably lower?
Are there any disadvantages of using slightly too many 7135 chips?
If your LED can handle 7A, no need for a nanjg.
If there were good direct drive drivers, I would suggest those. Otherwise, AMC based drivers work fine. Current might be a little lower though.
I don’t remember off the top of my head. The 7135’s have some voltage dropout. It’s pretty low though, like .1v. That plus they are not 100% efficient. It’s the cost to control the level of current going to the led.
I think our member Andi has added 25 or 28 chips in the past to a driver and that worked well. Cannot find the thread though....
Wait a sec. Its right here...
Edit: He only used 26 chips :-)
Too many? Like this?
From this post.
EDIT Ledsmoke beat me to it, but it's from a different post.
-Garry
If you have room, I say more 7135. ;)
The OP in the thread stated that
“Driver: 3-Mode (9100mA, 2800mA, 450mA) for LiMn. (measure @HIGH = 9,16A)
With LiIon´s it´s “direct drive”, i measure ~5A @ HIGH.”
I was just wondering how using more linear regulators (AMC7135) could provide a higher current than direct drive?
I'm under the impression that using a current regulated driver that you can "push" more current through an LED than it would take being direct driven. Seems this is the case with the Jacob A60 which usually takes around 2.1A with the stock driver (which is direct drive I think) and some have modded them with a 2.8A Nanjg driver to push more amps through the LED.
-Garry
I don't think that is correct but it's not the first time I'm wrong.
The 2.1A from the stock driver could be caused by inefficiencies with the driver itself or thin wires, etc. Ever tried DD an XML with an IMR battery? POOF!!!
Pretty sure that is wrong, the LED will take a certain amount of current at any amperage, say 2.1 amps at 3.4 volts. When you use a 7135 driver you are limiting the amperage flow, you are decreasing the voltage (by a minimum of about .1 volts) along with an extra decrease to it further dropping the voltage to whatever the LED will take.
Ok, well I could be wrong. How do we explain the Jacob A60 scenario then? I know people have direct driven the A60 (gords, speak up), so what are they getting on direct drive at the tail? Perhaps after adding a 2.8A Nanjg driver to an A60 would not give 2.8A at a tail cap measurement? Tom E where are you???
-Garry
Thanks for your explanation guys, but I’m still confused with the purpose of a linear regulator.
It’s supposed to provide a voltage drop so that 350mA would pass through a single chip.
In order to get a higher LED current, it would need a higher voltage, but i’m not so sure how the LED is getting a higher voltage than from the direct drive setup. The linear regulator would drop the voltage, not boost it. 
Ok, I see gords posted the A60 drew 3.17A direct drive. So what would happen if you added some AMC's for say 3.5A? 4.2A? Would it take? Or would you only get the max capable? Or os there no max and you would eventually push enough current to "POOF"?
-Garry
I upgraded the xRE on the A60 to a higher bin led (from Q5 to r2 i think) to take the higher amperage.
You can see some of the results from Foy's supercharged XRE thread.
Here ??
There's issues, maybe I can tailcap measure higher amps but no measured increase on the light meter, lightbox or throw, something like that (can't recall exactly). I know 2.8A was a waste, but 2.45A maybe did better than 2.1A.
I know I consistently seem to get more lumens on running regulated high amps than I do on direct drive at even higher amps, but, too many variables in the mod, so hard to tell the true cause. It would be a total PIA for me to do one thing at a time - but I'm lacking a proper bench setup to test configure/wire things up...
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)! 