RE: 2S 7.4v LiPo OK For RX and Digital Servos?
I would like to make a comment here. When a servo is specified for 6 volts nominal power supply (5 cells NIMH or NiCad) the only type of lithium based chemistry batteries that may be used, without a regulator, is 2S LiFePO battery with a voltage range similar to a 5 Cells NIMH battery pack.
A 2S LiPO battery has 7.4 volts nominal voltage (higher than maximun voltage of a fresh-charged 5 cells NIMH) peaking at 8.4 volts when fresh-charged. That means if somone uses 2S LiPO without a regulator to power supply a non HV servo, the servo is going to get fried very soon. Only HV servos may be power supplied with a 2S LiPO.