When you are using a driver such as the good version of the East-092 which uses direct drive on high mode, does the driver still monitor the cell voltage and if so, will it shut off before the battery goes to extreme low voltage?
Or is it the batteries job to protect itself?
Thanks,
Keith
Good question.
The jury is still out on that…
It does if it drops out of regulation. You will get a reduced amount of light output. 
But there is a lot of what ifs. Really comes down to drop in specific.
It depends on the firmware, just like any other driver. If it's not programmed to monitor the voltage, then it won't. The parts of the driver hardware that control the current-flow side of things has nothing to do with it.
edit, to see if anyone else notices how annoying it is when a post gets edited and edited and edited again and then edited some more, which screws around with the 'new' flags...
edit2: hi there! :)
edit3: whatcha doin' up here again? :)
edit4: so this guy walks into a bar, and the bartender says...
edit5: It's not nearly as annoying in this case because the thread's still on one page, but when it gets up to multiple pages and something gets repeatedly edited on a previous page, the 'new' link takes you to the edited post, and then clicking through to the last page clears all the flags and you have to drag out a calendar and a calculator and some scratch paper to try to work out which posts are actually new, and which ones aren't...
The MOSFET direct drive drivers don't regulate; they just turn the full amount of current on and off. The light will dim in all modes as the battery voltage drops.
But do the FET drivers have overdischarge and low voltage protection like the 105c drivers they were born from?
Yes, as long as the program has it built in, STAR does.
With STAR firmware they do, programmed to monitor the voltage and then flash 3x times and drop to a lower mode when voltage starts getting low
And the piggyback drivers (the ones using the custom boards with the ATtiny MCU driving a larger SRK board) does as well, but like comfychair said…“IF” the firmware of the micro controller is programmed to monitor it
I think DrJones builds also monitor as well
The MCU does not know what's on the other end of its PWM output. If the MCU is programmed with low voltage detection/protection, it will. If it's not, it won't.
So a light like the SupFire M6, with a BLF 17mm DD flashed with JonnyC’s STAR firmware, will monitor the voltage and give warnings, step down power levels until it has to cut off, right? The 4 cells are in parallell so they’ll all be protected by the circuitry.
Hope so. I need to run some longer term tests than what I’ve done.
Burns through nylon, I know that much! 
Should…yes
Wow…nylon melter, man pumping out the heat aincha
Guilty
x 10
Really need an option to edit without a post being marked “new”.
sorry
Thought I was just gonna keep my hand warm in my jacket pocket while taking pics of the eclipse last night. Didn’t realize it would melt the lining in my pocket. I might be slow, but I caught on to that one pdq! 
Is your name chet?
Chet’z nuts roasting on a hot emitter (-sung to chest nuts roasting on an open fire) 
Ok…enough derail…back to the thread
In direct drive, the cell will not, or at least not quickly, be discharged below the forward voltage of the led. This is in contrast to a boost driver that will drain it farther. This seems a potential problem with SK-68s with 14500s.
SK68’S in 14500 are running in linear regulated mode at about 800mA max thruput current, in 1.5vdc AA mode it runs as a 500-500mA boost mode
My point about the 68 is that if a 14500 runs down to 1.5 V, the driver will still be drawing 500 ma.
If you run a 14500 to 1.5vdc…you more or less killed it
The SK68 isn’t a FET or direct driver
I believe I found one of my SK68’s the kids left on…the 14500 was at .7vdc…kerchunk it in the trashcan and put in another one
This is why I really want to try the new 15DD w/ custom voltage protection firmware in it…
got one built, just haven’t got it programmed or put into the SK68 host yet…if it works…will be modding with a XM-L on a copper sinkpad (maybe even soldered to a penny) then epoxied in the pill