NexGen 750 with 14500 -> over-discharge?

I'm sure the answer to my question, or the NexGen specs, are arround here somewhere, but I can't seem to find them.

I have read about several people using NexGen sammies with a 14500 li-ion cell, but I can't figure out if the sandwhich will 'shut off' at a higher voltage than the 2.5v safe cut-off (I think this is the right voltage) for the cell, or whether I would need to monitor the cell's discharge to prevent over-discharging.

Thanks in advance,
-Brad

The nexgen will shut off with input voltages greater than output (Vf). But, the internal diode on the internal FET will conduct putting the board into a DD mode.

Under this condition the battery, internal diode and LED are what control the current to the LED which is uncontrolled. What I've seen is a J bin LED will draw around 1.1A in this condition which is overdriven, but, not out of control.

As the battery discharges and the battery voltage drops so will the LED current until the converter kicks in and starts regulating when Vin=Vout or lower.

I'm obviously still really new to this, and so I'm trying to figure out: At some point the converter board will no longer be able to sufficiently raise the input voltage to the voltage required by the LED, will it not? At this point would the LED shut off or would it go back into direct drive, and at what voltage would this be?

I guess my question is what is the minimum input voltage for the NexGen 750?

I hope this makes sense,
-Brad