Does anyone know how the AR12120 receiver chooses which 'battery input" to use under a given condition?
Is it be higher voltage, etc?

I'd like to power it on a larger electric model from the main flight batteries and not a stand alone battery. My initial plan is to power it from the BEC in a castle ICE 100, through the 3 wire throttle lead. The other power source is to be a stand alone Castle Pro BEC powering through the 'BATT 1" input on the AR12120.

Would it run happily here, and be able to fail over if one died? and since both BEC's are programmable for V out, should one be set to a slightly lower voltage then the other so the rx doesnt atempt to constantly switch under slight voltage drops from load?
Thanks

I don't think it is advised to run 2 different BEC's for your power. I thought about this some time back and believe Castle has something about it on their website. Could be a problem with grounding issues. What kind of model are you talking about?


Harry

And from the manual-
"It’s normal for one battery to discharge slightly more than the other. This is the
nature of a truly redundant isolated battery system. The battery that has the higher
voltage or lower internal resistance will discharge at a faster rate. Generally the
difference is negligible (less than 10%). Because of this it’s normal for only one
blue LED (Batt 1 or Batt 2) to be on when the system is not under a heavy current
load depending on which pack is providing more power."

Harry

Thanks Harry. I wouldnt run 2 BECs into the servo connector side of the rx, so I guess the next question is based upon the manufacturers note on 1 battery discharging more then the other. It would seem that the rx chooses one load supply over the other...if that's the case and assume I stay the course using only flight batteries would I be better off connecting the power form BECs into the provided batt 1\2 leads?

A battery wouldn't be the worst but its one more thing to manage
Its a H9 80" Taylorcraft- power 110 setup on 8s. Not a giant but big for me

Hey, that's a big plane for me too. I have a H9 Pawnee that is 80" and run that with a CC 20 pro with hundreds of flights on it. I have the 20 pro in 2 others as well. You would be fine with that in your Taylor. I am using duel A123 batteries with the AR12120 on another plane but that is using 10 hungry servos.

Harry

Not sure if this helps, but I run two power feeds (from 2 cells packs via UBECs) into a thrid-party battery monitor (essentially a diode in a box, I'm told), which automatically draws currents form the highest voltage.

In practice, the monitor takes current from each of the batteries in rapid succession in normal use. Should one pack fail then the monitor simply opts to use the remaining source.

Here's the Backer Monitor gizmo;

http://www.smservices.net/acatalog/L...del_Units.html

tim

That's the kind of device logic I'm asking about. Does the ar12120 perform a similair function?

You can't power this receiver through the servo bus. You must power it from the dual input power leads (the EC3 connectors).

That means you can't use the BEC in the ESC like you normally would. You would need to split it out so that you disconnect the red lead from the servo bus, and then insert it on the power bus.

You also need to power both EC3 leads (preferably from two different sources).

Why are you using this receiver if you're not using it the way it was designed to be used?

Andy

Originally Posted by AndyKunz

You can't power this receiver through the servo bus. You must power it from the dual input power leads (the EC3 connectors).

That means you can't use the BEC in the ESC like you normally would. You would need to split it out so that you disconnect the red lead from the servo bus, and then insert it on the power bus.

You also need to power both EC3 leads (preferably from two different sources).

Why are you using this receiver if you're not using it the way it was designed to be used?

Andy

Thanks Andy for the response that completely answered my questions. to answer yours: I'm not trying to use it in a way other than intended at all, The manual doesn't cover anything close to this question, it only speaks to using 2 batteries and how one will discharge more than the other etc, no mention of a BEC anywhere. So that is exactly why i reached out to you, to learn how it works.

One thing though I have plugged my BEC into the servo bus, and it did light up the rx, though i did not nor have I bound tit to my radio or gone any further then that. I lit it up and unplugged it, decided it was time to ask the man with all the spektrum answers

You don't want to power the servo bus. It's causing current to flow backwards through the FET that is controlled by the micro. Bad idea.

Andy

Not going to. Thanks for explaining why not to.