Originally Posted by DesertRat

I don't know if the SPX Stock Spec has the internal booster or not (I don't think it does, the V2 does), but in all ESC's going back to the dinosaur days of brushed motors the main heavy MOS-FET circuit which passes energy to the windings of the motor is completely independent of the internal computer. To do what your saying, just leave the switch for the ESC in the OFF position and then it will be powered running on the booster when the booster is plugged in, feeding energy to the ESC through the receiver into its signal harness as opposed to in 2s mode when power is fed from the ESC to its internal computer and then to the receiver. That will power on the ESC internal computer from the booster (6v). The ESC's main power connection doesn't even need to be plugged into the battery for it to power on its computer, only the signal harness. Still, the heavy-duty MOS-FET will continue to use just the 1s battery voltage and that is what will be passed to the motor.