Common caps for two escs?

[golfito]

Craig in my rc always tried to use external BECs. The turnigy are very economical and never brought me problems.







https://hobbyking.com/es_es/turnigy-...-for-lipo.html

https://hobbyking.com/es_es/quanum-1...tput-ubec.html

The latter and the castle creations waterproof will be next to try.

https://hobbyking.com/es_es/yep-20a-...ge-output.html

http://www.castlecreations.com/en/cc-bec-2-0-waterproof-voltage-regulator-010-0153-00

[CraigP]

Golfito, good selections! Remember to use the ferrite ring on the power out to Rec. I add a cap at the Rec, to form a low pass L-C filter at the Rec. I use about 47uF cap at the Rec. The problem with these switching regulators is that their noise output can be just a degrading as the ground noise!

[CraigP]

Here’s how I add the external capacitor to the Rec. I have connector housings and female pins, so I solder the cap to the pins, then place in the housing. I use an unused port on the Rec to mount it. Having it on a connector makes it easy to remove if needed. You can also direct solder the leads of the cap to the power wires, just ahead of the connector at the Rec. note the ferrite ring. You MUST use the ring if you add a large capacitor, or you could put your BEC into current limiting when powering up the model.

[golfito]

it is understood!
The smallest thing I found in my recycling was 100uF 36V SMD Aluminum and other electrolytic 100uf. But I can buy them.
*!** The low ESR capacitors if it was very complex to locate them where I live. Some distributors did not know them. But I could finally get it and arm my banks caps.

[TRUCKPULL]

Craig

Can you still a U-BEC wired to the main boat batteries with the Isolator between the ESC and the receiver??

Larry

[CraigP]

Craig

Can you still a U-BEC wired to the main boat batteries with the Isolator between the ESC and the receiver??

Larry

Yes, that’s how I’m wiring all my boats now. Please read the post above yours. Switching regulators are great, but they make a bunch of noise too, although not the same noise as ESC power ground. It’s really good to add that cap! Noise from the switching BEC is 1/5 th that of the ring alone. BTW, the “ring” forms a toroidal inductor, a special, low noise emitting type of inductor. When coupled to the cap at the Rec, it makes a great Low Pass filter, needed to keep things clean!

[golfito]

I'm using this for having a 7.2v output:
https://hobbyking.com/en_uk/quanum-1...tput-ubec.html

And I feed the servo hv and the RX de futaba.
I am adding the opto circuit between the rx / esc separately in each set esc / motor. The rx de futaba can handle two channels "for the dual esc".
I have the ferrite rings in the ESC and in the UBEC. I just have to place the capacitor in the RX.
My batteries will only share the ground wire (-).

[golfito]

Later I will try to get a mixer to test the internal motor rpm reduction as they commented. I'm surprised by that application.

[CraigP]

I think this circuit needs some proof that it will work. After all, we’re putting these things in our beloved boats! So I’m posting some scope shots of my test with them. I powered up the opto output with a small, 2s battery, real world to a BEC. I fed a 5V amplitude squarewave to each input at a frequency and duty cycle that’s close to a servo signal. They vary quite a bit anyway, no big deal... the first shot is a magnified view in time of the rising edge, scope at 4uS/div. As you can see, nearly instant and clean. The yellow trace on top is input and the lower cyan trace is output. The traces are both being displayed at 2V/div. This, to a servo or ESC, is instant ON. They next trace is the falling edge. It is 10X slower, 40uS/div, but still would be considered as nearly instant to a servo or ESC. The thing to note in these transitions is how clean they are, no over/undershooting. The next waveform is with the timebase at 2mS/div, which is showing three complete servo cycles. This is a duty cycle at the minimum servo position, and the fourth waveform is at the maximum servo position. I’m very happy with these results, and I hope by posting this, you won’t worry about them working as they should.

The picture insert messed up the order, or it’s beyond my abilities, lol! Anyway, the falling edge is the first, minservo position is second, max servo position is third, and the rising edge is fourth...

[TRUCKPULL]

Craig

Those results on the scope look very clean and precise with no noticeable lag.
Very good.

I have some 47uF - 35V caps , are these the right ones for the U-BEC output at the receiver?

Larry

[CraigP]

Those will work! You don’t need a super low ESR cap here, voltage rating is good too. You can use down to 16V on the Rec. I like to use what I have around, I’m thinking we think the same way!

[TRUCKPULL]

Those will work! You don’t need a super low ESR cap here, voltage rating is good too. You can use down to 16V on the Rec. I like to use what I have around, I’m thinking we think the same way!

OK now I have to find some plugs to solder them into, I know I have some somewhere in these 50 or so small boxes.

Larry

[CraigP]

Yeah, my world too! I’ve got a room full of boxes of small electronic parts. I go crazy trying to dig through it.

[golfito]

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[CraigP]

Well, it took me a long time to weld. I do not have such a good vision now.

Make a Craig modification. In the opto circuit. I have two individual optos now. Although they are on the same plate. And I'm going to use them in the futaba receiver, (dual esc). Therefore there are no bridges between both opto. And that led me to have two values of different resistances between the signal cable and the ground.
Can I ask you to check this for me?
Double Opto = the resistance value between the signal cable and the ground is 249 ohms.
Simple Opto = the resistance value between the signal cable and the ground is 498 ohms. The resultant of the resistances is correct. I understand that.
Your simple opto leave it with that resistor configuration?
Or I withdraw one of them?
[ATTACH=CONFIG]156377[/ATTACH]

Should I remove the resistance between pin 1 of the opto and pin 2 of the opto? and just leave the resistance in series between pin 1 of the opto and the signal cable ?.

Leave the values the same for both circuits. Those resistors are in there to make the light emitting diode inside the opto work at speed. A single channel can easily drive both both inputs with the values unchanged.