Posts: 5,315 Threads: 672 Likes Received: 3,155 in 1,743 posts Likes Given: 2,030 Joined: Jan 2016 Reputation: 139 26-Jul-2016, 03:25 PM (This post was last modified: 19-May-2017, 08:23 PM by Oscar.) Any one with noise on their video feed or system in general (or letting the magic smoke out of components) especially if using little bees, watch this video! I've never had a problem but i have always run my stuff of a regulator and had a low esr capacitor on the main supply, this vid explains why. Great stuff! - Little Bee ESCs (probably any damped light ESC) can be extremely noisy ranging from 5v-29v noise when being tortured. This is probably why they are known to kill video equipment.
- 1000uF low ESR capacitors are GREAT for filtering the main voltage line. A 1000uF regular cap with a 100uH inductor is a good alternative (but more expensive and heavier).
- A tiny step-down SBEC paired with a 1000uF low ESR capacitor completely removes noise generated by the motors, while stepping down the power to whatever you need for your video equipment.
Conclusion, if you are going to put a capacitor to your power to reduce power noise, use a large ESR cap!  ![[-]](https://intofpv.com/images/collapse.png) The following 12 users Like Oscar's post:12 users Like Oscar's post • , Apicalis, Khutchinson22, Drone0fPrey, fftunes, sloscotty, romvesen, NimhBot, mgy, Luc, 2strokesmoke, BigglesFPV Posts: 918 Threads: 83 Likes Received: 533 in 271 posts Likes Given: 498 Joined: Jan 2016 Reputation: 30 Excellent advice and great video, Never had the problem myself either, have always used good filters on my gear. • Posts: 5,315 Threads: 672 Likes Received: 3,155 in 1,743 posts Likes Given: 2,030 Joined: Jan 2016 Reputation: 139 (26-Jul-2016, 03:29 PM)BigglesFPV Wrote: Excellent advice and great video, Never had the problem myself either, have always used good filters on my gear. Many people use cheap chinese clone PDBs with crap to none filtering and often wonder why my video is so bad and why they burn As we are seeing more and more PDB integrated FC, filtering might go to hell (as space limitation and cost saving) and this type of DIY hack might come in handy • Posts: 99 Threads: 13 Likes Received: 24 in 15 posts Likes Given: 33 Joined: Jul 2016 Reputation: 3 Perfect, as I cycled home from the field yesterday, my first thoughts were to swap out the cheap pdb and relocate the rx on my kissed qav, this mod is really a no brainer • Posts: 328 Threads: 76 Likes Received: 191 in 85 posts Likes Given: 39 Joined: Jan 2016 Reputation: 16 Wow good link! I had video problems too. I'm using matek pdb with lcfilter, maybe it's overkill but no more video noise for me. • Posts: 1,070 Threads: 70 Likes Received: 742 in 378 posts Likes Given: 577 Joined: Jan 2016 Reputation: 44 Thanks for sharing that vid Oscar. Great to see results from someone with scientific approach • Posts: 146 Threads: 20 Likes Received: 21 in 14 posts Likes Given: 86 Joined: May 2016 Reputation: 0 (26-Jul-2016, 08:58 PM)Konrad Stepanajtys Wrote: Thanks for sharing that vid Oscar. Great to see results from someone with scientific approach I agree. Great video. Makes me want to bust out the O scope. Enjoyed the video very much. • Posts: 5 Threads: 0 Likes Received: 0 in 0 posts Likes Given: 0 Joined: Jan 2016 Reputation: 0 Nice one! Now I can refer my friends keep questioning me about esr cap on pdb! • Posts: 1 Threads: 0 Likes Received: 0 in 0 posts Likes Given: 0 Joined: Sep 2016 Reputation: 0 Hi!!! i have a question, the capacitor in this kind of filter is a low esr? http://www.readytoflyquads.com/rtf-lc-filter-3amp-2-4s, if not, will be better if i change for a low esr one? thanks!!! • Posts: 146 Threads: 20 Likes Received: 21 in 14 posts Likes Given: 86 Joined: May 2016 Reputation: 0 Excellent post and video. Answered all the questions I've had about installing my new ESC's and explaned it well.  • Posts: 1,149 Threads: 50 Likes Received: 704 in 450 posts Likes Given: 1,189 Joined: Sep 2016 Reputation: 30 (22-Sep-2016, 04:45 PM)joke Wrote: Hi!!! i have a question, the capacitor in this kind of filter is a low esr? http://www.readytoflyquads.com/rtf-lc-filter-3amp-2-4s, if not, will be better if i change for a low esr one?
thanks!!! Just as a notice, the one you linked to is HUGE and heavy. Here's a smaller version which i'm gonna test on my next build: http://www.readytoflyquads.com/mini-rtf-...-3amp-2-4s However the idea is to additionally use low-esr caps on the PDB and/or escs.
Great video, thanks for sharing. • Posts: 307 Threads: 18 Likes Received: 69 in 48 posts Likes Given: 33 Joined: Sep 2016 Reputation: 9 Is it not always good to use a capacitor even if you don't use FPV.
Maybe your FC will also work better and maybe even your RX?
But is it better to place the Cap close to the ESC or to the Lipo.
I think the ESC because these make the noise on te power line. • Posts: 5,315 Threads: 672 Likes Received: 3,155 in 1,743 posts Likes Given: 2,030 Joined: Jan 2016 Reputation: 139 To be honest i don't know how noise in 5V power would affect Gyro on a FC without testing it further. But I have used littlebee on my LOS quad and it flies just fine without power filtering for FC. i wouldn't bother to add capacitors to the power if i am flying line of sight. We are picky about noise only because it's really obvious in video. • Posts: 2,410 Threads: 136 Likes Received: 1,790 in 1,052 posts Likes Given: 3,302 Joined: Jan 2017 Reputation: 50 28-Feb-2017, 04:51 PM (This post was last modified: 28-Feb-2017, 08:22 PM by Drone0fPrey.) Excellent excellent video! Much help ty!
This is my first build, Im using DRCs Pulse PDB which has filtered 5v and 12v. So in theory if I add the low esr cap to the batt inputs I should be good to go, yes? (Just double checking)
Also 16v, 25v or 35v for 4s build? • Posts: 65 Threads: 3 Likes Received: 36 in 20 posts Likes Given: 6 Joined: Feb 2017 Reputation: 1 28-Feb-2017, 07:51 PM (This post was last modified: 01-Mar-2017, 09:50 PM by Helibus.) I'm sorry, but I just can't sit silent on this. The conclusion regarding adding a low ESR capacitor may very well be valid, but I found the technical validity of the video marginal. That video would be chastised quite strongly in electronics circles.
Is the motor current going through this wiring? Breadboards and jumpers like he used are mainly intended for logic circuits, not for carrying the high currents that his motor testing would be using. The jumper wires are at best 24-gauge, and could even be lighter than that. He doesn't really explain or show how he has everything interconnected, but it's safe to say he's adding resistance and inductance into the circuit because of all the jumper wiring involved. A more technically accurate approach would be to wire up everything as it would be in real life, then adding in just the scope probe for monitoring.
What is he using for a ground reference point for the oscilloscope? It's critical that the same point is used in comparison tests - as soon as the scope ground lead moves to a different point in the wiring, you lose the ability to draw any conclusions from comparing the measurements taken.
I couldn't continue watching the video when he compared the noise from his low-ESR capacitor to the the capacitor salvaged from a power supply. Did no one notice that the low ESR capacitor is tested plugged directly into the breadboard, but the salvaged capacitor is tested hanging while plugged in with long wires? That's not a subjective comparison. The wiring on the salvaged capacitor added resistance and inductance that is by definition going to diminish the benefit of the capacitor. The low ESR capacitor may have done just as crappy of a job if it had been tested with the long wires on it.
Again - I don't dispute that adding a capacitor is a smart thing to do, and that a low-ESR one is a better way to go. I'm just saying that the video could have done a better job at making the argument. • |
