Quite sure I remember reading that in here somewhere Drunk. What it doesn't have is a low voltage cutoff, and depends on the
batteries protection circuit to shut down when depleted.
I'm sure Doug will clarify this when he pops in here.
The board is designed to run on both 16340 or 123A's so that's why there is no low voltage cut off, the range would be different with 3.7 vs 3 volt cells and even brand and dropout rate... that was important to me in the design becasue if you were absolutely in need of power with no place to charge, you could just walk into a store and buy a set of 123a's for a camera and you'd be back to vape'n....
here is how and why it has a 3amp rating..
1st: The regulator chip-set in the board is rated for 3 amps... but it' won't hurt itself if you ask it to go over, and it will if its thermal protection say's it's ok to do so.. but that would only be briefly..
2nd: The board itself is copper on fiberglass and has traces (happy copper lines), the width of these traces dictate how many amps they are rated to carry... the output trace is rated for 3 amps... there is some safety margin in this spec.... but the spec is 3 amps.... any more would be a strain on the system... sure it can do it.. but that is not what it was designed to do.....
So we
have to recommend 2.4ohms and higher, it's safe to say... we can't assume everyone who buys our toy knows how to calc power.... but a 1.8 ohm coil would fine for the system at all voltage levels on the dial 4~5.5.....
Using anything lower than that will require doing the math to keep ya under 3amps....
example:
so lets say you have a 1.5ohm coil loaded up....
with the dial set to 4-volts, you'd be runnin' 2.6amps, burning 10.6wattttz ... so that's just fine
now set the dial to 4.5-V, now your at 3 amps, burning that coil at 13.5 watts,,,, still in spec, but danger zone if you don't know the math, so that's why
"WE" can't say you can fire that coil...
now let's say you have a 1.8 ohm coil...
dial set to 5.5, well that's only a hair over 3amps... burning at almost 17watts.. still just about in spec.....
hope that helps, that is why we say 2.4 ohms and higher.... to keep the average joe or mary in check and give specs that keep the safety margins in play... There is more to the board than what i covered, but if your into electronics in the slightest.. taking that little puppy out and hacking it to do other tricks is not hard in the slightest... it was made to be easy to tinker with...