I would be interested by an answer to this question too... The ESC used in the Easystar II RR ( MULTIcont BL-20 SD ) has a BEC that delivers 5.5V is it OK to plug it into the APM2 output rail ? Thanks.
I was told 5v
I'm surprised it is not more clearly spelled out in the manual, but it seems that 5v +/- a small amount (like 0.2v) is what is required for APM 1. I assume APM 2 is similar. This is based on searching through old posts.
I am using a separate UBEC that outputs 5v,which has never cause a problem. It is just a shame that a lot of ESC's output 5.5v, which causes APM to do strange things.Otherwise I could have a neater setup inside my plane.
I would avoid plugging your 5.5v BEC into the APM 2 rail. You can buy a UBEC for <$15 that will output the correct voltage and be safer.
Thanks for the answers guys!
I made a switchng regulator using LM2576-5 it gives perfect 5v output now APM is working ok you can find data sheet at;
it is 3A 5volt switching regulator with wide input range. i have isolated APM and servo voltages also.
There is a LM317 voltage regulator on the APM 1.0 for external power source. Does the APM 2.0 have something similar?