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Thread: Common caps for two escs?

  1. #151

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    Very impressive. Thank you very much sir!

  2. #152

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    Nice work Craig. Really appreciate the knowledge and wisdom.

  3. #153

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    Craig

    Those last three posts of yours are perfect.
    Most people would not do what you have done here.

    This way anybody that can handle a soldering iron (very small tip) can build one for them self.

    Larry
    Past NAMBA- P Mono -1 Mile Race Record holder
    Past NAMBA- P Sport -1 Mile Race Record holder
    Bump & Grind Racing Props -We Like Em Smooth & Wet

  4. #154
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    I was thinking: Give a man a fish, he eats a meal. Teach a man to fish, he eats for life! First one is the hardest, then they roll from there! If I can answer questions just post them here. I’ll post some pics of the tools I used. Thanks Larry!

  5. #155

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    Thanks Craig. Very cool reading. I might just make a few.
    Club GalvaPhong

  6. #156
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    Guys, hold off on the Opto Board builds! I’m testing with my Tactic TR325 receiver and it won’t drive the opto input... it only has 20mA of loading, so I’m pretty surprised! It did work on my FlySky setup. In any regards, this can’t be a flakey design, so I need to come up with some buffering. I’ll let you know when I find a solution...

  7. #157
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    Playing hooky from work, a benefit of working from home! I removed the 2, 232 Ohm resistors on the input and replaced with a 1.00K, same as the output resistor. That had a very insignificant impact on the timing throughput, so its a good solution. I’ll have to update the schematics. Looks like there is no need to drive the input that hard. Note, the optoisolators are a Panasonic part, known for high quality. If you use something else, there may not be enough gain across the device and it won’t work the same. I removed the posts with the wrong values to avoid confusion and unclutter the thread.

  8. #158
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    Problem resolved on the Opto Boards. I deleted one resistor and changed the value of the other to match the resistor used on the output. This reduced the Parts List by one component. Here is the schematic and board shots for the Single Motor Opto Board. Note: I didn't re-shoot the pics, so they still show two resistors on the input side.
    Attached Images Attached Images
    Attached Files Attached Files
    Last edited by CraigP; 01-25-2018 at 11:33 AM. Reason: Schematic still had errors, put in new version.

  9. #159
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    Here is the 1 Input, 2 Motor Opto Board...
    Attached Images Attached Images
    Attached Files Attached Files
    Last edited by CraigP; 01-25-2018 at 11:35 AM. Reason: Schematic still had errors, inserted a new version

  10. #160
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    Here is the 2 Input, 2 Motor Opto Board...
    Attached Images Attached Images
    Attached Files Attached Files
    Last edited by CraigP; 01-25-2018 at 11:40 AM. Reason: Schematic still had errors, inserted a new version

  11. #161

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    Thank you very much for the work you do.
    Today I try to start assembling a circuit.
    *!** The previous one tries to desoldar the resistances in parallel that add them ... but an attack of little patience ended up throwing it in the trash basket ... it worked too, like ?, I still do not know.
    I try to assemble and test with a futaba tx and comment.
    Greetings.
    Hernan

  12. #162
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    Did you see the new schematics? You need to increase the series resistor and take off the parallel resistor. Try the values on the schematic, 1K Ohm. This works with Panasonic PS2501, but don’t know if it will work with 4N25. I need your help to verify that. Can you do that and report?

  13. #163

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    Craig,
    I just tried it on the breadboard and the ESC does not work. TX / RX turnigy / flysky, optp 4N35, 1k resistors
    27267957_1786909541610779_441792067_o.jpg
    27393687_1786909551610778_562591907_o.jpg
    27330173_1786911981610535_1646977704_o.jpg

  14. #164

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    Invert the signal and ground wires at the output. Remaining the first circutito that I present. And it worked!

    27330173_1786911981610535_1646977704_o (1).jpg
    27267259_1786927544942312_1803098496_o.jpg

  15. #165

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    Last edited by golfito; 01-23-2018 at 11:06 PM. Reason: video

  16. #166
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    The connectors are wired to be compatible with Futaba style of wiring. My boards hooked right in. After changing the input resistance, it all worked good. I have them hooked up in series after the mixer board, and that works great.

    I’m not sure what changing the output resistor does, other than load the ESC BEC a bit more. It’s not a big deal... The output transistor is in the Emitter Follower mode of operation. So the current to the ESC input is not governed by that resistor. It’s there to bias the emitter, nothing more.

    It would be nice to see scope shots, but I understand not having one. You’re working blind! You have enough patience, that’s for sure!

  17. #167
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    Quote Originally Posted by golfito View Post
    Invert the signal and ground wires at the output. Remaining the first circutito that I present. And it worked!

    27330173_1786911981610535_1646977704_o (1).jpg
    27267259_1786927544942312_1803098496_o.jpg
    Golfito, I fixed those errors you found in the schematics. Could you please check these and let me know if they look like what you built? Thanks!

  18. #168

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    Hello Craig, tomorrow I will try to assemble a plate and comment.
    I am also trying to understand how to calculate in a practical way a capacitor bank. I am reading a very complete post in this same forum.

  19. #169
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    Golfito, the most important thing about a cap Bank is the capacitors. You may have a problem getting good one there. You can use many, smaller caps to get around that. If you want me to look up specs on what you might use, I would be happy to help. Just let me know.. I got a new project I’m building too. I like building things!

  20. #170

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    Thank you very much. I also enjoy building.
    The capacitor banks have already been assembled. Something generic. Not special. I just do not seem to follow advice correctly. And I exceeded a little in total capacity. 470ufx35v for 10 units each bank. http://www.nichicon.co.jp/english/products/pdf/e-hv.pdf
    That's the only low ESR I could get ...
    And the ESC T-180 brings 1000ufx35 for 3 units of Rubycon.
    Total each ESC T-180 will have 7700uf. It will run a double motor, 6SP1, 5A 70C lipo, TP 4050 1700KV, X447.

  21. #171
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    Yes, those are 1.8A@100Khz. So you got 10.... That should be pretty good. Looking good!

  22. #172

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    Hello, some other advance?
    I will try to restart the assembly of a PCB board.

  23. #173

  24. #174

  25. #175

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    Well change the resistance from 1K ohm to 220 between the opto and the RX. With the TX flysky it worked, but not so with the radio futaba. But I'm using optos 4N35 and not the ps2501.
    https://www.youtube.com/watch?v=e9RX...ature=youtu.be
    https://www.youtube.com/watch?v=8tLB...ature=youtu.be

  26. #176
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    I found the same thing, worked on one reciever but not another type. The PS2501 is a higher gain device than the 4N25, which was designed for slow switching and analog isolation circuits. It might give you trouble... The PS2501 worked very well going from 220 Ohm to 1K. Here’s a pic in my new boat, a UL-1. It’s in between the water lines, aft of the ESC. This is a single channel Opto Board.
    Attached Images Attached Images

  27. #177

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    I think I got a couple of ps2501-1 ... when they arrive I will try 1K on my RX futaba.

  28. #178

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    Quote Originally Posted by CraigP View Post
    Needs to be a conductor as big as the wire size going to the cap Bank. Just to let you know, round wires create external magnetic fields around them very easily. Those magnetic fields creates inductance, which is called “leakage inductance”, because it’s not directly coupled to a power source. This causes a loss and increases ripple current/voltage on the system. Flat copper plate does not create near as strong of an external field, so no leakage inductance. That reduces ripple... your wire helps, but you’ll still have quite a bit of ripple on that wire at currents over 120A.
    Hi Craig, your discussion here has me interested! I normally build my cap packs on short pigtails w/8-10x 1000uf and it seems to work. Original caps built into the esc that used to run very hot now with the cap pack run cool. Hence my assumption they are working.

    So talking single motor/esc, if I wanted to instead add 1 or 2+ of your 3600uf caps would it be better in your opinion to use the flat copper plate somehow as opposed to just soldering across the power wires close to the esc board? If so how would you do it? Thanks!

  29. #179
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    Flat plate reduces the added inductance that wires make. It all depends on the current you are using. Flat plate starts to have a good advantage at 120A and up. I usually get 1/16” copper plate, cut it to the desired shape and drill holes into the plate to mount the caps. I attached some pics of a big, 350A cap Bank to give you a reference.
    Attached Images Attached Images

  30. #180

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    Thanks man! So I assume you then skin back the power leads and solder to respective plates?

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