Hi guys, I have an insight as to why some people might be having ESC issues…
I am using Multistar OPTO 45A ESC’s… on my new Hexa, they worked on APM and direct to Rx, so I couldn’t work out why they wouldn’t work on Pixhawk… they seem to require 4-6V on the +/- to power them, which the Rx or APM was doing, but the Pixhawk is only putting out 0.9V on the servo/ESC output side…
I have to power the output side with another reg… then the ESC’s can boot up…
is this normal??? or is mine faulty?? 
exactly as designed.
the APM power module is not supposed to power everything.
you can, however, add servo-side power for redundant power supply to APM.
Thanks Andre,
however the Pixhawk is powering my Rx through the SBUS cable,
do you know, or have you tried looping power back from the Rx back into Output side of Pixhawk as an easy fix?
or am I asking for problems?? it’s not a lot of current, just powering 6 opto ESC’s…
it’s just annoying having to run another reg to just power the ESC’s…
Cheers
BOB
Yes, PPM and SBUS input are powered from the internal voltage selector.
you could route back the power, there’s no technical reason not to do it. (you won’t blow anything) but it’s simply not the best practice, as you bypass, instead of taking advantage of redundant power.
The only thing you need to be very careful about, is that the APM power module is (AFAIK) max 1.5A
and you need to consider the sum of the load you hook up to it.
ESC’s shouldn’t use very much anyway.
Thanks again Andre…
yeh I think i’ll loop it back… as running the reg is not redundant, as if it fails. the whole thing shuts down anyway… as it’s the only thing powering the ESC’s…
I’m using a new V4 power module I got from infinity::::
infinity-hobby.com/main/prod … s_id=10303
which is great because it can take 8S input (I’m only using 6S) but it has 3A output, so surely that can power Pixhawk, telem, and 6 ESC’s right??
Cheers
BOB
Yes, 3A is plenty unless you add powerful servos or other crazy stuff 
Annoying but more redundant and reliable
[quote=“BobFlint”]…
I am using Multistar OPTO 45A ESC’s… on my new Hexa, they worked on APM and direct to Rx, so I couldn’t work out why they wouldn’t work on Pixhawk… they seem to require 4-6V on the +/- to power them,[/quote]
No, they dont need to be powered by the PIXHAWK. They have an internal BEC, which is powered by the flight battery. The OPTO just says, that they dont come with an 5V Output.…