The esc should regulate the voltage going to the receiver no matter if you run 14.4,16.8,0r19.2 . If the esc is rated at 12-16 cells then the bec should put out 4.8 or 6 volts . The only time I would run a receiver pack is if I needed 6 volts and the esc would not supply that amount of voltage .
This is incorrect.
Most BEC's only function correctly to spec up to around 12NiMh/3-4 LiPo cells. The ESC may be able to operate up to 20 cells NiMh but the BEC must be disabled. Perfect Example is the Castle Creations line of boat ESC's.
As battery pack voltage increases, it is much harder for the BEC to drop the input voltage to servo/receiver voltage. This in turn creates heat. To much heat will destroy any electrical component and most definitely shorten the life span. Another point to keep in mind is the BEC may not be able to provide a regulated voltage to spec while over volting it. This will lead to higher voltages then normal at the receiver. Too much voltage
may cause twitch, studdery servos, or interference.
You should run a receiver pack in these cases:
Voltage exceeds BEC limit
Current drawn by Servo(s) exceeds BEC limit
Hydra 120
SPECS: Width: 1.6" (40mm)
Height: .6" (14.5mm)
Length: 3" (76.5mm)
Weight: 3.2oz (93g)
Max Volts: 25V
Resistance: .00043 ohms
Cells w/ BEC: 5-12 NiCd/NiMH, 3S LiPo
Cells no BEC: 5-20 NiCd/NiMH, 6S LiPo
Ryan