ORIGINAL: MikeEast
the problem was not with the recievers, the problem is using the wrong batteries for the application. This is true with any radio system. I would say that if you are performing aerobatics on a plane with several high output servos (100+ ounce rated output) then you might need to use a 6V setup and high capacity batteries especially if you are not very aware of what to look for and when you are at "no go" voltage.
Yup, the poster stated a problem with the DX7 e.g. "battery issues".
AFAIK there ARE NO "battery issues".
Even standard servos can draw upwards of 1800mA at full stall torque, and higher torque servos even more.
That means that ONE fully deflected servo hitting a limit can quickly deplete a battery, or push a battery beyond it's capacity to supply current, exactly as you said.
However this is NOT a problem with the transmitter as Kavik alluded to... nor is it a problem with the receiver or radio system...
Rather it's a "user error", where the pilot has not calculated the required battery capacity needed and adjusted accordingly.