SmartRTH setting: mystery solved

[yorlik]

Li-Po cells don't like getting so low, and it's good you're not doing it for other batteries. What needs complete depletion is the "smart" part - otherwise it may incorrectly compute remaining energy.

So - complete discharge is only needed to calibrate counters in the internal ICs.

Right mostly, but doing the BELOw 8% to recalibrate, like you said earlier, does NOT completely discharge the cells; it just brings them down to a low level (without looking up my old notes I think it is 3.4v/cell) not depletion. Deplete a cell and you have a good chance you just totally destroyed the battery.