UBEC to power receiver and CC3Dseperately
« on: August 09, 2017, 09:51:50 pm »
Hi Libre Pilots,

After a quick search around the forum I could not find an exact answer. So here goes...

I am planning for a FPV plane build and am trying to get my head around wiring everything up and spreading the power load around to try and not overtax any component. In the future I will change the CC3D to a Revolution for GPS functions (at the moment I have a CC3D and no GPS).

I am wanting to use a 10A UBEC to power my CC3D, receiver and fps gear.

Please advise if this would work without blowing up my receiver and or CC3D?

The UBEC I have my eye on plugs into the battery and then has 2 seperate 5V outputs (so 2 pairs of wire coming out i.e. 2x +5V and 2x -ve).

One of the UBEC's +5 and -ve would power the the camera and OSD. Transmitter would be power by the battery (12V).

The other would power the receiver and the CC3D. I was thinking I would make a splitter cable from from the UBEC and plug one into the Batt/VCC port of the receiver (this would power the receiver), I will only plug the throttle signal cable from the receiver to the CC3D, not the + and - (so that the CC3D is not powering the receiver, only receving the signal).

The CC3D will be powered by the other split of the cable. Can it be plugged into servo output port 6 (or any unused output port) to power the CC3D?

So, apart from adding additional wiring, would this work and would their be any potential benefite? Or should I just use the UBEC to power the CC3D and the the CC3D power the receiver?

Thanks for your time.

Regards,

Hoender.

f5soh

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Re: UBEC to power receiver and CC3Dseperately
« Reply #1 on: August 09, 2017, 10:31:11 pm »
Quote
I am wanting to use a 10A UBEC to power my CC3D, receiver and fps gear.
Please advise if this would work without blowing up my receiver and or CC3D?

You should only check the voltage needed, around 5V.
10A is the maximum current provided by the UBEC according to the load connected on it.
You should not need this big 10A UBEC to power OSD, receiver, camera and CC3D, a smaller 3A UBEC will be fine to power all the 5V devices at same time.

Generally with big UBEC there is two power wires but they are not really separate, they are just connected to the same source/regulator output because only one servo connector cannot resist to 10A current.


Re: UBEC to power receiver and CC3Dseperately
« Reply #2 on: August 10, 2017, 08:16:44 pm »
Thanks f5soh,

I understand the basics of volts, current and power etc. 5V for the voltage and the UBEC will only supply the current that is drawn by all the circuits connected.

If I add up an estimated current for camera, osd, receiver, CC3D and 6 servos (I understand the servos won't all be working at the same time but lets assume I am banging the sticks around) then I estimate I would be close or mayber over 3 amps? Or am I over estimating the current draw?

This is why I thought a slightly beefier UBEC would be great (also for future expansion).

So could I power the receiver and CC3D seperately the way I described? Or instead of "over engineering" (as I am prone to do) keep it simple and use the UBEC to power the CC3D (and servos) and the CC3D to power the receiver?

Re: UBEC to power receiver and CC3Dseperately
« Reply #3 on: August 10, 2017, 08:31:19 pm »
To each his own, but one power supply for receiver, servos, FC, etc. is good enough if it can handle the whole current load.

Of course different servo types have different stall currents, and you probably won't be running them that hard, so it is really up to you to guess or measure what your current need is.

The only place I have ever used multiple power supplies is for an FPV system to have a separate battery from my flight battery, and I don't always do even that.

f5soh

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Re: UBEC to power receiver and CC3Dseperately
« Reply #4 on: August 10, 2017, 08:38:51 pm »
If you power all the stuff with the 10A Ubec, the only limiting thing is sometimes servos a little slow at 5V.

Of course you can put two separate UBEC, one for camera/OSD and another for "RC" = Receiver/CC3D/servos with a little more voltage.
This solution give more insulation about changes in voltage that sometimes disturb camera or osd and also give a simple way to disconnect the FPV stuff while flying LOS.





Re: UBEC to power receiver and CC3Dseperately
« Reply #5 on: August 11, 2017, 01:26:41 am »
You can also use a power distribution board/block/center what ever  you want to call lt. it opens a whole other plethora of options that you can add to your craft. I believe the power distribution board are the inexpensive ones under $10 and then you dont need a ubec then you hook your esc to it and the rx and the fc power to it and the signal wires where they go

Re: UBEC to power receiver and CC3Dseperately
« Reply #6 on: August 15, 2017, 08:36:58 pm »
Thanks for the advice/tips.