I've received my APM 2.5 kit and I find it has a cable that looks like it is for power control with two high current in-line yellow connectors and a fly-lead control wire.
I've done my best to read the instructions but I'm confused about where this cable fits in and where it should be plugged in.
Any advice appreciated. Especially any link to a definitive set-up page for this unit.
I forgot to mention that the existing build has an ECM and I assume that it plugs into the APM as the other servos do. The problem is how and why this new cable is to be used.
The new beta Wiki would be helpful to you but... that sounds like your power module.
The high current connections put the unit in line with your battery and the power distribution board (for a multirotor) or the ESC (for an airplane/rover).
The smaller connector goes to the APM and provides life support as well as voltage/current information.
HERE is the page with the 'Power Port' indicated.
Unfortunately your link is broken.
If it's in-line to the ESC then I assume the only function is monitoring? I can't see a use-case where it controls power? However, I can see a use-case where it provides power to the APM-2.5 via the fly-lead independently of the ESC?
That was odd..never happened to me before..my apologies.
HERE is another try. The little cable goes into the hole labeled 'PM' as seen from the top of the case.
You missed my comment "...provides life support as well as voltage/current information."
By life support I mean it regulates down the battery voltage to the specified APM input voltage.
Use the module to ease your system connections and to help make sure the APM is correctly powered.
Mind you, J1 should not be installed when using the Power Module.