Do I need a BEC or UBEC on my APM-controlled octocopter, if I plan to use a 6S battery? I'm putting an APM2.5 into a Tarot IronMan 1000, for carrying larger cameras and gimbals and I understand that I'll need the 6S to handle the weight of the copter, camera, gimbal, retractible gear, etc. However, I have heard from sources who may or may not be properly informed, that the Ardupilot doesn't like 22 volts. Is this true? If so, what BEC/UBEC is best for the APM2.5?
FYI, I'll probably use 3515-15 400kv motors, with as yet to be determined 40A ESCs. Other drains on the battery will be GPS, telemetry, ultrasonic sensor and two 5.8GHz video transmitters (one for pilot and one for camera operator). As a EE, I calculated this out to the best of my ability and my calculations appear to confirm what I've been told about needing a 6S. But I'm new to building these things (flying, yes - building, not so much experience), so I could be missing something. Any help would be appreciated. Thanks.
BTW, I have not found a local hobby shop that knows anything about the APM. They all seem to want to sell me on NAZA or Wookong.