LibrePilot Forum

Users => Vehicles - MultiRotors => Topic started by: Stuartambient on March 02, 2016, 08:48:28 pm

Title: BEC and CC3D
Post by: Stuartambient on March 02, 2016, 08:48:28 pm

I have this pdb (built into the frame) which has a 5v bec built in.  I'm wondering about 2 things though.  First off, it is rated as 5v 1a.  So is that going to be enough power or do I need more amps? My rx is a small flysky 6ch. 
Second question, do I need to know what kind of bec it is, because I know there is UBEC, and switching becs? Just a little confused is all.  Appreciate any help.  Thank you!

Title: Re: BEC and CC3D
Post by: f5soh on March 02, 2016, 09:00:45 pm

Its a switching Bec here, no issue for just a CC3D + receiver
Those bec type are usually rated at 2A

Title: Re: BEC and CC3D
Post by: Stuartambient on March 02, 2016, 09:54:51 pm

Quote from: f5soh on March 02, 2016, 09:00:45 pm

Its a switching Bec here, no issue for just a CC3D + receiver
Those bec type are usually rated at 2A

Not this one though, it's rated at 1A.

Title: Re: BEC and CC3D
Post by: f5soh on March 02, 2016, 09:59:53 pm

Sorry 2A have a bigger IC

Title: Re: BEC and CC3D
Post by: Stuartambient on March 02, 2016, 10:25:57 pm

Quote from: f5soh on March 02, 2016, 09:59:53 pm

Sorry 2A have a bigger IC

Okay, so 1A is enough amperage for the fc / rx.  Thank you!

Title: Re: BEC and CC3D
Post by: NicholasDavid on March 03, 2016, 12:32:48 am

Yeah I'm running a x4r-sb reciever and a cc3d on a 5v 500mah pololu. They both use about 150-200 mah. The reciever probably less.

Title: Re: BEC and CC3D
Post by: Stuartambient on March 03, 2016, 12:51:03 am

Thanks Nicholas, good to know! I'm sure my little flysky rx doesn't require much.

Title: Re: BEC and CC3D
Post by: NicholasDavid on March 03, 2016, 03:59:53 am

Your welcome. You could also use an old esc for its bec if it has one. Just take out the signal wire and cut or desolder the 3 motor leads.

Title: Re: BEC and CC3D
Post by: Stuartambient on March 03, 2016, 11:56:37 am

I was thinking of that but as the pdb has too 5v regulators might as well take advantage of them.  Thanks !

Title: Re: BEC and CC3D
Post by: Brassman on March 03, 2016, 12:01:51 pm

esc with built in bec are Always linear non swiching right? and less than 1A I Think.

Title: Re: BEC and CC3D
Post by: Stuartambient on March 03, 2016, 12:06:05 pm

I only have a few from the same set, which are linear rated at 1.5a. 

Title: Re: BEC and CC3D
Post by: jbarchuk on March 04, 2016, 05:56:38 am

1A or 1.5A or whatever, that's not a 'target.' That's an 'absolute maximum.' Meaning above that rating all bets -may- be off.

How close you want to push up to that rating depends on whether you want to 'bet the farm' on it or not.

If you're out 2.5km and a sudden downdraft causes the motors to SURGE past the limits to hold a flight path, voltage may drop, systems may reset, and depending on what failsafes are set to and whether it can recover fast enough will determine if the flight continues or the aircraft drops in a lake.  :-[ :'(

For SAFETY purposes, use an amp rating that is twice the maximum likely needed.

Under race conditions in a relatively close space where a couple of grams add a bit of agility it may certainly be worth the risk.

For PERFORMANCES purposes, by all means push the envelope.