Pulling the pin?

[Dave Martin]

I've seen some conflicting advice relating to ESCs with linear BECs and whether or not the + pin needs to be disconnected on all but one of ESC to FC connectors. My understanding is that this is only necessary with switched BECs and that linear BECs will happily work in parallel.

I'm going to be connecting ESCs with linear BECs to my APM 2.6, but I'll be using the separate power module (and therefore leaving the bridge jumper off). Do I need to disconnect some of the ESC pins or is it just some form of 'best practice'. If the latter, then why is it better disconnecting them? I thought it might be to reduce wasted power draw/heat but they won't be powering the FC so it seems this would be minimal.

I suspect I'm showing my ignorance so feel free to point this out. I'm not sensitive

 

[Jackson]

I thought it might be to reduce wasted power draw/heat but they won't be powering the FC so it seems this would be minimal.

My experience with dc-dc linear regulators was with E-cigs. If the the switch to active the load (an atomizer) was put after the regulator the batteries would slowly drain even when not being used/activated. The switch had to be before the regulator (between it and the batterries) to avoid the drain.

 

[Dave Martin]

My experience with dc-dc linear regulators was with E-cigs. If the the switch to active the load (an atomizer) was put after the regulator the batteries would slowly drain even when not being used/activated. The switch had to be before the regulator (between it and the batterries) to avoid the drain.

Not sure its relevnt but from a bit of reading it seems that low dropout regulators will always draw some 'quiescent current' even with no load. Still, given that the advice is to pull the pin on the load side (fc end) I cant't see how this would stop the problem. It would still have power on the input side I think. Then again I'm no electronics engineer

 

[Dave Martin]

I found good thread on this.

http://fpvlab.com/forums/showthread.php?29139-Why-disconnect-redundant-power-from-esc-s-bec/page1

It seems that with switched BECs its much more of a problem and disconnecting the pins is definitely recommended. With Linear BECs the problem is less and given that they already run hotter, issues of slight additional heat from BECs 'fighting' with each other is negligible. Its still advised though as leaving them all connected can cause noise which might interfere with onboard video equipment.

Probably best to just pull the pins, especially if powering the FC from a separate power module.