Common caps for two escs?

[Jesse J]

Is there any reason to not do this:

Twin set up, common battery bank... I'm thinking of putting the caps in the parallel harness, as opposed to dedicated set of caps for each esc after the split.

Thoughts? I'm not imagining a problem, but would like to learn from somebody else's smoke if there is a reason to NOT.

Thanks
Jesse

[CraigP]

The only thing that comes to mind and the reason I wouldn’t do it is because you are doubling the ripple frequency. These frequencies are not synchronized, so they will dead beat on each other and there will be periods where the ripple current will be double, which is pushing the caps too far. We are already pushing capacitors well into the danger zone on FE boats. I would use two different banks, but share a common ground. So in essence you would be making a 3-leaded capacitor Bank.

[Jesse J]

Hmmm, would you mind posting a schematic? The ripple factor is the part I was concerned about.
I imagined the caps as shock absorbers damping out the ripple. But I can see how ripple from esc A could go also to esc B and get everybody cornfused.

[CraigP]

Yes, I’ll post a pdf showing how I would construct it. I use copper plates in my cap banks to keep resistance low and help to cancel the unwanted inductance in the conducting elements. I’m going to be building a dual motor hydro this year, and will use this exact method..

[CraigP]

Could you share with me how much current you expect to run to EACH ESC? BTW, the battery will be split into a 3-leaded configuration to match the cap Bank. The drawing will show that...

[Fluid]

Caps should be as close as practical to the ESC, so use separate banks for each ESC. For high frequency ripple, more, smaller caps will work better than a few big ones. That said, I’ve had great success on SAW setups using three to five 1000 mF caps, each one bridging the two power wires rather than all of them on a pigtail.

.

[CraigP]

Here's a PDF of the Cap Bank I would use. As Fluid mentions, it is extremely important to get it as close to the ESC as possible. Using a common ground, you can use on the BEC outputs from one of the ESC's to power the electronics. If doing that, be sure to isolate the second ESC's output by removing the middle wire on the signal in at the ESC. A capacitor I'm having great results with is this from Mouser Electronics:

P/N 661-EGPD500E362MM40H, 3600uF, 50V Aluminum Electrolytic Capacitor. This capacitor has the highest ripple current rating and lowest ESR than any other cap I've found in this range. This is suitable up to 8S operation. FWI, caps with higher voltage rating always have lower ESR than a reduced voltage counterpart. Always apply a 20% de-rate to the voltage spec of a cap, never use it at the defined voltage rating! I hope this helps you...

[TRUCKPULL]

I always wire my ESC's together, so each motor see's the 2P setup.

Would I wire the caps the same as your pic or differently,

Right now I have 3 on the board and 5 on a pig tail on each ESC. 6-S 2P (Turnigy 180 - V2's)

Larry

[golfito]

I received help to calculate the amount of microfarads and this went for my T180 v2:

155884
155885
155886
155887

[Jesse J]

Here's a PDF of the Cap Bank I would use. As Fluid mentions, it is extremely important to get it as close to the ESC as possible. Using a common ground, you can use on the BEC outputs from one of the ESC's to power the electronics. If doing that, be sure to isolate the second ESC's output by removing the middle wire on the signal in at the ESC. A capacitor I'm having great results with is this from Mouser Electronics:

P/N 661-EGPD500E362MM40H, 3600uF, 50V Aluminum Electrolytic Capacitor. This capacitor has the highest ripple current rating and lowest ESR than any other cap I've found in this range. This is suitable up to 8S operation. FWI, caps with higher voltage rating always have lower ESR than a reduced voltage counterpart. Always apply a 20% de-rate to the voltage spec of a cap, never use it at the defined voltage rating! I hope this helps you...

Thanks Craig, I think I'll do something similar, but bring the batteries in series. I'd like them to get drawn down together. This may require separating the cap banks completely. I'll post a picture when I get it wired.

[CraigP]

Sounds like you’ll be using a separate external BEC and isolate both BEC outputs from the ESC’s? You need to keep your ground potentials close between the two ESC’s, or you’ll form unwanted ground loops thru the control side. Sounds like you know what you want, I’m sure it will all work great!

[Jesse J]

Ground loops? Only one I know about is the one when my rocket with pontoons did when I was a kid.
Yes external receiver pack, and all very short wires. I've pulled the red power wire out of both controllers.

[CraigP]

Hmmmm, confused :confused2: Jesse, you’ve got 5,573 postings on an FE forum and this is the first time you’ve heard of ground loops? It’s only the #1 cause of erratic receiver behavior. I’m finding that hard to believe...

[golfito]

Excuse me,
would the loop be a junction node between the ground terminals of both sets of ESCs / motor / battery?
I understand that on my boat the ground wires that come out of the ESCs (RX) are the only ones that are attached. Also external BEC and both positive cables isolated in the esc. Use a "Y" harness where you eliminate the red wires.
I saw the drawing in pdf ... magnificent !. And I understood that I am missing the ground connection in both systems.

[CraigP]

A “ground loop” is not a purposeful wire. Rather, it is a unintended current flow thru some of the ground conductors. It is the biggest reason people experience gremlin like behavior in their boats. I’ll try and give an example. Suppose we wire the duel ESC’s as the OP suggests. It seems simple and straight forward. Wire each side independently, where one batt set feeds one Cap Bank and ESC and another similar pack feeds the other side. The grounds and hots are kept separated between the two systems. Now let’s assume this is running 4s on each side. Each ESC has a BEC output, but only one can be potentially used. The problem is WHICH battery is going to supply the power for the control electronics, either thru the BEC from one of the ESC’s or from an External BEC, fed from one of the batteries. The OP says no BEC, use a separate battery pack for the control electronics. That’s fine, but it doesn’t address the problem, which is the Y cable you mention.

You see, no matter how you connect this configuration, that Y cable is going to try and short the two grounds together. The problem is that the grounds EACH have their own ripple voltage, and the peaks and valleys are out of phase, or asynchronous to each other. When the ground voltages don’t match, then that Y cable is going to try and short this ripple voltage difference and guess what, the control electronics are going to lose the battle. It causes a large current flow in the ground of the Y cable, which can easily disrupt any part or all parts of the control electronics.

It is for that reason that my PDF shows the grounds of the two batteries closely tied to each other on the common ground plane of the Cap Bank. Now the ripple voltage will only appear different on the positive side of each battery. Now, you can tie the positives together too, and many do that so that they discharge evenly. But that desire comes at a cost. Tying the two positives will now force all caps to see the voltage/current ripple of BOTH ESC’s. They are out of phase to each other, but at times they will add up to huge values, and this is very hard on the caps. It’s just exactly like the manner huge rogue waves are developed at sea. Ocean waves as they get large, get asynchronous to each other. Every once in a while, two big waves add in height and you have a 100’ wave staring at you, from nowhere!

Same thing happens in an electrical system. So I put up with the small amount of uneven discharge. I alternate the packs every other run. But my caps run cool, and I don’t have huge waves of electrical power to contend with. My apologies to the OP, I’m sure he would prefer to see this posted elsewhere.

[golfito]

Thank you for taking the time to detail the situation.
Excuse me for interfering. I found it very interesting and useful.

[golfito]

Make a connection with a conductor between both earth connections of the esc or caps. Thank you very much.155916

[CraigP]

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.

[Jesse J]

Hmmmm, confused :confused2: Jesse, you’ve got 5,573 postings on an FE forum and this is the first time you’ve heard of ground loops? It’s only the #1 cause of erratic receiver behavior. I’m finding that hard to believe...

Don't think that since I've been on this forum for ten years I know everything... or that I want people to think that...

[CraigP]

I didn’t imply that you thought you knew everything. I just thought that making that rocket crack and making light of an electrical problem that has probably caused people to suddenly run their boat into something hard was in bad form. Most you veterans could run circles around my knowledge on boat setups, racing tactics, prop configurations and many other topics. But I know electrical systems, and the bizarre behavior they can produce. I’m trying to help someone! I put effort into making a drawing that illustrates my point. It didn’t feel very good having that effort minimized.

[golfito]

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.


Thank you very much sir!
These topics are very interesting. They clarify many random defects that occur in electrical systems.

[Jesse J]

Craig, you will find that The OP has a dry sense of humor, but I have no intentions of belittling anybody or an opportunity to learn.
My comment about the ground loop was a jab at nobody but myself referring to a very memorable failure. I never excelled in physics 2 electricity and magnetism. I'm a visual learner and without schematics I can't visualize the electromagnetic enigma. I honestly have never heard of your ground loop before.

This is the perfect place for extended discourses and I welcome all opportunities to reduce my electromagnetic ignorance.

So the y harness is the power, not the radio wires? Is this gremlin behavior like when you unplug one esc from the battery, hit the throttle and the unplugged motor turns a little?

I calculate that I'm pulling 70-90 amps average in the application... so far. It will only go up with bigger props.

The "ground" is the electrical sense not the physical. I'm getting there...
I'll need to go back through the posts several more times as it is still not crystal clear.

Thanks for putting up with me :moon::laugh:

[Jesse J]

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.

What do use for this? I'm assuming it's for the cap board.

[golfito]

"Is this gremlin behavior like when you unplug one esc from the battery, hit the throttle and the unplugged motor turns a little? "

I experienced that situation when I had placed the harness "Y" and had only removed the red wire that was attached to the RX. (the two red cables of the esc had been joined by the harnes "Y").
Remove all positons / reds from the "Y" harness.
Excuse my English, I try to understand.

[CraigP]

What do use for this? I'm assuming it's for the cap board.

I get my copper plate from online metals.com here’s a link: https://www.onlinemetals.com/merchant.cfm?pid=7147&step=4&showunits=inches&id=966&top_cat=87

This is 0.062” material, good for 150 A at 1/2” width strips. For higher current, I double the strip up, by soldering to one side then stack another plate on top, then solder the two together. I made a big cap Bank for Dasboata (Chris). You can get some details from him too. It has stacked plates. That was a 300A Cap Bank to get his surface car to 150mph.

[CraigP]

"Is this gremlin behavior like when you unplug one esc from the battery, hit the throttle and the unplugged motor turns a little? "

No, that was probably the residual charge left on the ESC’s internal caps. This ground loop behavior really only shows itself while the vehicle is under load. It needs to be at high amp output, then the ripple problem and loops start to show up. For most of us, we’re just running our boats then suddenly it takes a weird turn or the motor cuts out or the ESC just burns for no apparent reason. The reason many ESC’s burn is because the ground loop current upsets the microprocessor and it glitches the program. This causes the ESC to lose lock on the rotation of the motor. If it sends pulses incorrectly timed, the resulting current overload will smoke the mosfets.

[golfito]

I'm going to implement it on my boat. I was able to get 10 AWG cable. It is my first construction and I am reviewing all the electronics before executing it.

[Jesse J]

Here is a vid from a while back.
im still not completely there on the ground loop thing.
In this video, the second motor is not plugged in to any battery. The receiver line is connected to a y harness, but the esc power leads are both unplugged.
https://youtu.be/Qyq4xSFAnsM
Thoughts?

[CraigP]

That’s cool! Just to re-cap:
1) ESC 1 is plugged into a battery, while ESC 2 is not.
Question: Do either ESC’s have a BEC?
2) Both ESC’s are plugged into a Y Cable
3) The Reciever is powered up, assuming this true since the motors are responding to a speed input.

Question: Hard to see from vid, but does the unplugged motor rotate in the proper direction, i.e. opposite of the other motor.

I think I know what’s happening, but need verification and question answered. Bottom line, you may be demonstrating the exact nature of the problem I was describing. Meaning wire connections can have unattended consequences! Thanks for sharing

[fweasel]

That’s cool! Just to re-cap:Oh, I see what you did there. Clever.

[CraigP]

Oh, I see what you did there. Clever.

I haven't done anything, but the questions didn't get answered. I think what is happening is that the unplugged ESC is getting power from the Y Cable and charges the ESC's caps. Then when he hits the throttle, that cap charge spins the unplugged motor for a short period of time. The Y Cable can't supply the current to keep it going, so the BEC is probably going into current limiting, which cuts off the receiver, then the process repeats. I don't think it is mutual magnetic field coupling because the motor I think (it was a question I asked) is turning in the opposite direction. Plus there is a lot of metal mass on the out runner and it does a good job of soaking up most of the magnetic field. Any field that leaked that much would make a pretty inefficient motor.

This is a good video showing that current can flow through wires that we wouldn't think of as high current carriers and actually should not be. I love out runners!

[Jesse J]

That’s cool! Just to re-cap:
1) ESC 1 is plugged into a battery, while ESC 2 is not.
Question: Do either ESC’s have a BEC?
2) Both ESC’s are plugged into a Y Cable
3) The Reciever is powered up, assuming this true since the motors are responding to a speed input.

Question: Hard to see from vid, but does the unplugged motor rotate in the proper direction, i.e. opposite of the other motor.

I think I know what’s happening, but need verification and question answered. Bottom line, you may be demonstrating the exact nature of the problem I was describing. Meaning wire connections can have unattended consequences! Thanks for sharing
Yes to all questions.
Your explanation seems very plausible. I agree that it's probably not the magnetic field as I proposed in the vid.

[golfito]

That same try to describe on my boat with both T180.
A single battery. External Bec. "Y" cable. I had just removed the red wire from the "Y" on the side of the RX. Both engines turned ...
Remove the other two red wires from the "Y" side of the "ESCs" and only the motor that had the lipo connected was working.

[CraigP]

So as interesting as all this is, the main thing to keep in mind is to watch for unintended current flows in the ground, or minus side. All the electronics rely on the fact that the ground is electrically quiet for everything to work as designed. So I stick to the advice that dual setups should use what is essentially a 3-terminal capacitor, as I posted in the PDF on page 1 of this thread. This keeps the ground quiet. If your ESC’s both have opto-isolation and no BEC, then using that kind of cap with and external BEC will work well. The problem really comes in when you have LV ESC’s such as the T-180, that has an internal BEC. I have not seen a wire diagram that will hold down potential noise problems. I build a small PCB, that has a dual opto-isolator on it. Each channel is independent. I run a control cable from the receiver that provides the throttle signal, ground and power to both opto-isolator inputs. Then each ESC is hooked up to an opto-isolator output and that ESC’s BEC provides the power for the output side of its corresponding isolator. This completely eliminates ground and power loops, but you have to build it. I haven’t found a PC board on the Internet I can just buy. If I run across one, I’ll come back here and post the part number and source with a new PDF to wire it.

[golfito]

Very interesting!
I can try to build it the pcb.
I'm not an electronic technician, but I'm curious.
https://static.rcgroups.net/forums/attachments/1/3/7/0/6/a4171075-156-esc.JPG
I found it sailing ... would it be a combination of two of these circuits?

One question that occurred to me: futaba has the "DUAL ESC", some benefit in using two channels of the RX? instead of using a "Y"?
https://www.manualslib.com/manual/1201892/Futaba-4pls.html?page=74
I do not think the entries in the RX are isolated.

[golfito]

http://www.eastbayrc.org/TimTips/TimsTips_DualBatterySetups.htm

https://www.wr-store.com/index.php/optical-isolator-c-22?osCsid=gqhstg1n0q5pdq6i4l1t71q572

[CraigP]

Very interesting!
I can try to build it the pcb.
I'm not an electronic technician, but I'm curious.
https://static.rcgroups.net/forums/attachments/1/3/7/0/6/a4171075-156-esc.JPG
I found it sailing ... would it be a combination of two of these circuits?

One question that occurred to me: futaba has the "DUAL ESC", some benefit in using two channels of the RX? instead of using a "Y"?
https://www.manualslib.com/manual/1201892/Futaba-4pls.html?page=74
I do not think the entries in the RX are isolated.

The circuit is close. That’s a circuit diagram, used to show a configuration. It’s not an actual working circuit. If fact with using the battery directly, you could burn out the input on the ESC... They “usually” have an upper voltage rating of 7.5V. The second link is showing the capabilities of that transmitter to do Dual ESC Mixing, a powerful function in the world of twins! It allows you to speed modify the two motors based on rudder input. It’s a feature usually found on the better, more expensive radios. This does nothing for the electrical noise problem. Both ESC’s are still sharing a common control ground.

[CraigP]

http://www.eastbayrc.org/TimTips/TimsTips_DualBatterySetups.htm

https://www.wr-store.com/index.php/optical-isolator-c-22?osCsid=gqhstg1n0q5pdq6i4l1t71q572

Nicely done Golfito!! The first link shows a solution under “Method 3, Power Domain Isolation, Opto Isolator”. The second looks like a viable part, but I like the cable layout better in the first link. It puts the opto isolator closer to the ESC, to help prevent noise pickup over the wire run. I would need to see the schematic of this part. I’m not sure how they are wiring the outputs on the opto isolator.

[CraigP]

It appears that West Mountsin Radio no longer makes that opto isolator. That leaves option 2. The east bay rc link on post #36 is in my opinion, a must-read for any FE guy! Loaded with good stuff!

[golfito]

I have a radio futaba and the necessary receiver ... do not use that function for recommendations in the FB, Elite RC B ...
I understand there is no noise isolation.
Also thinking about a kill swicht if it is possible that adapted work.
http://www.8fly.it/open2b/var/catalog/product/files/787.jpg
http://www.8fly.it/open2b/var/catalog/product/files/789.jpg
I hope you understand what I'm trying to describe.
https://hobbyking.com/en_us/opto-gas-kill-switch.html


And I found this:

http://www.mtroniks.net/prod/RC-Accessories/ZGM.htm#description

https://www.ebay.com/itm/D213-Opto-isolator-Breakout-Board-Module-ILD213T-Optoisolator-Microcontroller/401346520936?epid=869911972&hash=item5d721de768:g:Lo8AAOSw~XpZQAQq

http://rc.305.cz/view.php?cisloclanku=2015100004
https://www.ebay.com/itm/4-Channel-Opto-isolator-IC-Module-Arduino-High-and-Low-level-Expansion-Board-/311520477631?_ul=AR

[golfito]

https://drive.google.com/drive/folders/0B8i5PxQ5XywyZkFKankzVFVQOFU

These I can get in my city. Could it be used to build the circuit?
On Saturday I will try to ingest.

[srislash]

The circuit is close. That’s a circuit diagram, used to show a configuration. It’s not an actual working circuit. If fact with using the battery directly, you could burn out the input on the ESC... They “usually” have an upper voltage rating of 7.5V. .
Ah hah!!!!! I have been curious about this fact for awhile now but have not seen any manufacturer list specs. I would like to run a HV system but feared the ESC wouldn’t take it.

BTW guys this is a real good read. I have not experienced any of the loop issues but see room for improvement. Mmm, did lose one side of a twin ESC once mind you with no real cause

[golfito]

156293

This is more approximate. I think it could be useful.
I also followed the advice and link the ground wires of both ESCs.
156294

[CraigP]

Let me draw you a schematic tomorrow. These aren’t showing enough detail. The previous post wasn’t quite right either. You did connect your grounds together in the picture, that’s good. But I don’t think that the forum in general understands the difference between wires and flat plat conductors. It’s just too deep a discussion for this forum, I’m only going to be ridiculed, so I’m not going to explain. Just know there is a big difference! I’ll just continue to build my cap banks in a manner that makes the most sense to me. Not trying to be difficult, it’s just a matter of choice. Your on a good path, I really like your quest to know more. But the open forum just doesn’t work for me. If you want, you can PM me an email address and we can take this discussion elsewhere. In fact, please do that first and I’ll send the schematic to your email. Thank Golfito, look forward to direct communication!

[golfito]

You are very kind. Thank you.
I will send you a private message.

[CraigP]

Ah hah!!!!! I have been curious about this fact for awhile now but have not seen any manufacturer list specs. I would like to run a HV system but feared the ESC wouldn’t take it.

BTW guys this is a real good read. I have not experienced any of the loop issues but see room for improvement. Mmm, did lose one side of a twin ESC once mind you with no real cause

Shawn, will include you on the email traffic. If others have a serious interest in this discussion, please PM me an email and I’ll get you on the list. I think this is the best way to keep this topic going in the positive and constructive direction.

[srislash]

Shawn, will include you on the email traffic. If others have a serious interest in this discussion, please PM me an email and I’ll get you on the list. I think this is the best way to keep this topic going in the positive and constructive direction.
Thanks Craig, you know I'm all about getting things right.

[ray schrauwen]

156293

This is more approximate. I think it could be useful.
I also followed the advice and link the ground wires of both ESCs.
156294

Very interesting circuit. Subbed. Might send email but I'm just lurking.

[CraigP]

Very interesting circuit. Subbed. Might send email but I'm just lurking.

Would love to put you on the copy list Ray! Just posted an updated schematic for dual setups that addresses this ground loop or noise issue, whichever you prefer to call it.

[Jesse J]

Shawn, will include you on the email traffic. If others have a serious interest in this discussion, please PM me an email and I’ll get you on the list. I think this is the best way to keep this topic going in the positive and constructive direction.

Too bad you got your feelings hurt even after I explained that I was NOT ridiculing you. The hobby is not worth getting all stressed out about.
I'd like to learn, but not at the expense of tangling over misunderstandings.

[CraigP]

Hmmm, you might want to read what you posted over again. It’s easy to say I’m a snowflake that gets feelings hurt easily. Actually, thought you might want to know, received a PM from another forum member asking if I had done something to upset you. Seems I’m not the only one that didn’t get what meaning you were trying to convey. Some of us are serious about stopping unexplained failures and achieving extremely reliable boats. Sorry we got off track, but you posting about this being all my problem tells me you have other things on your mind. I wish you the best sir and I still enjoy and learn from most of your posts.

[TRUCKPULL]

Shawn, will include you on the email traffic. If others have a serious interest in this discussion, please PM me an email and I’ll get you on the list. I think this is the best way to keep this topic going in the positive and constructive direction.

Why take this to a private conversation?
There are probably a lot of us here on the forum including me that are interested in reading this discussion.

I run a duel motor cat with two ESC's
Red wires disconnected on both ESC's
U-BEC for power to the receiver.

Also both ESC's wired together on the battery side (+ and -) so each ESC sees the 6S2P setup.

Larry

[CraigP]

Can I ask you a question? Do your ESC’s have Internal BEC’s in them?

[TRUCKPULL]

Can I ask you a question? Do your ESC’s have Internal BEC’s in them?

YES


Larry

[CraigP]

Well Larry, we are discussing the problems encountered when running that exact configuration. So this schematic that’s being discussed is really different than your configuration. I’d expect you’re happy with your setup, but are you interested in reading about the potential problems? Before we went off site, it was discussed how running your batts and cap banks in direct wired parallel can create a lot of added stress on the caps, which are already stressed pretty good at these amp levels. The two motors don’t run exactly the same, so the caps see some really high current surges as the motors beat frequency to each other. That was the reason for posting the 3-terminal cap schematic earlier in the thread. Do you see any validity in what I’m saying?

[TRUCKPULL]

Yes the schematic in post #7 is what really me interested in this topic.

For my setup of 6S2P - would the connections for the 2P be before the cap bank or after the cap bank?
Two black going into the ESC's joined together, and the two red going into the ESC's joined together.

I race my boats, what I have noticed in the past before I started running the 2P setup is that towards the end of a race, on the last couple of laps the boat
would start to pull to the left down the straightaways.

Seeing that the hull is a CAT, in the turns (right hand) the outside prop is pushed down into the water more then the inside prop.
So as the race goes on the outside battery is getting run down more then the inside battery, causing the left hand pull.

Larry

[Jesse J]

Larry I noticed that the outside motor really draws more mah, 10-20% more! And exactly why I started this thread. Sincere thanks to all!

So I am thinking this as my plan.
This schematic should satisfy all participants in this thread.
If not please speak up.

[TRUCKPULL]

Jesse

Your schematic is exactly what I have now.
I like the cap bank that Craig posted in Post #7
Put now am getting confused, as he says NOT to connect the two red Battery wires together.

This means NO 2P setup.
This does NOT work for me when Racing. ( I need the 2P setup)

I can see it now I come out of the last turn, my boat stars to drift to the left. The guy right behind me passes me for the WIN on the inside.

Or I drift out an take out an other boat, CD calls me DQed for not holding my lane, now between the two boats there is over $2,000.00 in damage.


Larry

[CraigP]

This is a tough problem. I can surely see that one batt pack may get less volts on it at the end of the run. Also, I was planning on putting in a small PCB mixing board, that will slow the in-bound motor under steering command and make it turn better, but that will cause differential battery drain as well, especially on a novel course. I’ve read some racers like the transmitters with channel mixing, but they are a bit pricey. There’s a solution here, and I’m interested in exploring it because my boat may show the same problem. The 3-terminal cap solves the excessive ripple problem (well even under single ESC systems, the cap takes it on the nose). Larry, if you give me a bit of time on the CAD, I think I can come up with something that gets the noise out of the control system while allowing for dual battery pack connection. I’ll post something here tonight, but I’ve got to run some calculations. I’ve got an electrical simulator that can give me a pretty good idea on how it will work. Probably get simulation results tomorrow. This is a good one, I like it!

[CraigP]

Larry I noticed that the outside motor really draws more mah, 10-20% more! And exactly why I started this thread. Sincere thanks to all!

So I am thinking this as my plan.
This schematic should satisfy all participants in this thread.
If not please speak up.

Yes Jesse, that’s the power connections, and that’s the direction it’s got to go to fix the asymmetrical battery drain. But the “problem” comes with the interaction of the control hook up with the battery connections. Jesse, does your ESC’s in the dual have internal BEC’s like Larry’s setup?

[CraigP]

Here's what I posted off site, looks like some other folks may be asking the same questions. This has a separated battery pack, but you may find the information about the control side insightful.

I got a pretty good run on this and have this PDF to discuss. One of the things to note on this schematic is that the ESC batteries are in no way tied to the control electronics. The ESC’s common ground plate is also isolated. I show a separate battery to run the receiver. My thinking on that is an External BEC is typically a switching voltage regulator. These devices work by producing short bursts of current through an inductor to translate that charge to another voltage/current. They produce a lot of noise, that’s why most of the come with those little “rings”, which are ferrite toroidal cores. The power is wrapped around them to suppress the noise these devices create. Since a dual motor configuration is by nature, a noisy electrical environment, it doesn’t make sense to use a “noisy device” into the Receiver, the very thing we are trying to make noise immune.

Also, The ESC’s depicted on this drawing are LV ESC W/BEC types, meaning they have an internal BEC. This is very common when running ESC’s common to the 4S battery range, which is probably what you guys are running per motor. If so, then the batts are 4S type each, for a total of 2 in the system. Each ESC is using its internal BEC to bias the output of the opto-isolator associated with it. It is the ONLY thing these BEC’s are used for. As you can see, the grounds are tied for the ESC’s power input at the common “plate” of the Cap Bank. If you choose to use wires, then realize you are degrading the ripple reduction effort by as much as 4X. I’m going to try and explain this. Wires are round, and as such, any time an electrical current flows through them, they can easily create a circular magnetic field around the outside of the conductor which has a closed path. By establishing this magnetic field, you are turning that “wire” into an inductor. The only way to remove the inductive effect is to remove the closed, circular path of the magnetic field. This inductance greatly adds to the ripple problem. Now a Flat Plate, not being round in nature and being designed with the correct length/width size, makes it very difficult for that magnetic field to close in upon itself, or wrap around the whole plate. What the fields end up doing is to form many, little circular fields on the face of the plate. These consecutive fields, end up cancelling each other and viola, the magnetic field’s effect disappears! Read that over a few times, it took me a long time to understand this.

Also note, that the receiver’s power (+) is not required to bias the inputs to the dual opto-isolator. The power from the receiver battery is basically all being used by the rudder servo, which is good, leaves more power for servos with higher torque outputs. I always recommend putting a small, electrolytic cap on the receiver directly. That may have to get soldered into the wire leads if you don’t have enough free ports on the receiver. Rudder servos in boats pull big-time current pulses, and this can cause a power fluctuation in the receiver and glitch it into performing incorrectly. (Like steering into a stone wall or the shore).

The most probable cause of ESC failure is power disturbances on the control side, which glitches the microprocessor inside the ESC. It will lose track of where the correct motor position is and will no doubt over amp the ESC as it tries to get back on track. To relate to this better, you may search for threads written by airplane guys where they report blowing the ESC when landing the airplane and the prop grounds out on touch down and stops rotating. This stops the prop and the same problem occurs, ESC loses true position, guesses wrong and BLAM! So it’s imperative that the ESC has a clean source of controller power (on the 3-terminal wire).

Well, let me know where you agree and disagree. If you guys need part numbers and such let me know. I can look some stuff up.

Note: This is NOT the new schematic I'm doing in response to Larry and Jesse. But it shows a good loop isolator scheme on the control side. These are LV ESC W/BEC's

[Jesse J]

Yes, as I have stated, they are disconnected and I am using a 2s rx pack.
Per suggestion, the orange rectangles are Copper plate 1/2" by 1/16" I intend to attach to some non-conductive plate; plates were obtained from the links in one of Craig's posts.

This thread is getting better and better!!

[srislash]

A challenge!!! Nice. You guys know I can’t believe none of us have really come up with any of this or at least figured out it can be a problem. It is kind of like running the twin setup with both BEC’s. It may run ok for awhile but at some point it will give a stutter and POP!!!

I know of a number of people whom have lost one ESC of a pair with no real explanation. I am one. There is inline fixes(or has been) that I guess air guys have made as shown in post #36. but it never transferred to here

[CraigP]

I've got a new schematic. The copper plates at the caps are good, but needing to connect both batteries together will somewhat nullify that. This is something a bit different. I needed to make just a few changes to my original simulation and my hunch looks good. So we know wires can become inductive and that under normal conditions, is not what we want. But sometimes you can use it to an advantage, if applied properly. This design splits the cap bank into two sections, for each side. I show one cap at each battery. The batteries are tied together, then longer wire runs are made to the ESC, where there is a two-cap bank on each ESC. Those wires running from the batteries on the top need to be at least 4" long, to achieve the correct inductance value. This creates a complex type of electrical filter, known as a Pi Filter. It is a C-L-C combination, and is very good at holding noise at a point of interest, which is the ESC's. The noise I'm talking about is the high current ripple voltage caused by each ESC, and it's frequency is dependent on the speed and coil switching sequence of each motor. These will never be the same, so we want each ESC to essentially "see" its own ripple, and not that of the other motor. This circuit accomplishes that by using the split capacitors and tying them together through an inductor, which is in this case, at least a 4" length of wire of #10AWG. Sounds like you two (Larry and Jesse) are running opto-coupled ESC's on both sides, which is the superior selection. If your running LV ESC's w/BEC, then you should build the opto-isolator board as shown to break the ground connection that is inside the ESC's of this type, from the ground signal on the speed input connector (control input) and the ground on the battery input. Its that connection that is glitching your microprocessors, as I mention on the previous post. Simulation says this will work guys!

[CraigP]

A challenge!!! Nice. You guys know I can’t believe none of us have really come up with any of this or at least figured out it can be a problem. It is kind of like running the twin setup with both BEC’s. It may run ok for awhile but at some point it will give a stutter and POP!!!

I know of a number of people whom have lost one ESC of a pair with no real explanation. I am one. There is inline fixes(or has been) that I guess air guys have made as shown in post #36. but it never transferred to here

I've been losing uP's for 30 years! I just really got on top of this problem over the last 10 years. This is what I do... The airplane guys do have an in-line fix, but it doesn't work all the time and their motors are usually drawing much less current, which makes a big difference. At our current levels, if the uP looses position, you're pretty much going to let the magic smoke out! We got no safeties, and I haven't been able to even design in a practical fuse without incurring big time power loses. We're hanging it all out!

[golfito]

I try to follow you. It brings back memories of school.
Thanks for the time you spend. The proposal is very interesting.
This Saturday I will start with the double opto.

[golfito]

https://youtu.be/w55g1ILrVjE

I was able to find about 4N35 near home to be combined.
It works, just that I do not have an oscilloscope to verify the signals.

[golfito]

Craig, I consult: I have a 4pls futaba and allows to connect separately each ESC to the RX. It could be a good option too. How should I modify the resistances on both sides?

[CraigP]

Nice job! If you have separate outputs for each ESC from the receiver, then just make each input connect to its corresponding output. There is no need to change any resistance values.

The circuit should work good and notice I was able to design out the inverting transistors, while making the circuit have better edge transitions. The last schematic I posted is what I’m going to use on my dual. The guys here have been describing non-matching battery drains, which is a problem when using the batteries in an independent manner, as originally shown on the first schematic. So I would say the 3-terminal plate cap Bank is not the best choice. What do you think Golfito?

[CraigP]

https://youtu.be/w55g1ILrVjE

I was able to find about 4N35 near home to be combined.
It works, just that I do not have an oscilloscope to verify the signals.

I love it! You do great work! I used bread boards for years like you have there, brings back some great memories. Looks like the circuit is clean and can be adapted for the dual. Are you going to build it onto some pad-per-hole PC board and solder it all in? That’s what I was planning to do...

[CraigP]

Yes, as I have stated, they are disconnected and I am using a 2s rx pack.
Per suggestion, the orange rectangles are Copper plate 1/2" by 1/16" I intend to attach to some non-conductive plate; plates were obtained from the links in one of Craig's posts.

This thread is getting better and better!!

On high current (over 150a) parallel up those plates, to make it 0.125” thick. Plate needs to be 1/2” at its smallest width, or choke point to pass the current unfettered. I find it easier than soldering wire, and if you glue the bottom side of the plates to some FG insulation board, makes a great assembly! You are right on the battery drain problem, that is not acceptable...

[CraigP]

Golfito, does your 4-chan Futaba system have channel mixing on the transmitter?

[golfito]

I love it! You do great work! I used bread boards for years like you have there, brings back some great memories. Looks like the circuit is clean and can be adapted for the dual. Are you going to build it onto some pad-per-hole PC board and solder it all in? That’s what I was planning to do...



Thank you! here it is known as "protoboard".
If I am also remembering how to use it. I'm pretty rusty.
If today I bought some perforated plates to try to put it together. But it was a complicated day, I can not reason or think much ... jajajaj
With respect to the TX, if you can mix channels. is a 4pls futaba and the RX (R304SB T-FHSS 4-channel telemetry enabled receiver)
http://manuals.hobbico.com/fut/4pls-manual.pdf
From page 70. Do not use it yet. I did not program it either. I had it reserved for when this ship ends.

I also have the modified flysky / turnigy. That allows you to do channel mixes and use Rx from 3ch, to 8ch. But I do not want to use it on this ship.

And returning to the resistors of the circuit ... then it is not necessary to modify the resistance that is in parallel and the one that is in series in the circuit (anodo-cathode).

I hope not to say nonsense, to top it all, I use the google translator.

[CraigP]

I understand you good! You go through much effort to communicate with us. Hard Work! Yes, your Futaba has the right stuff, it’s here: Dual ESC Mixing "DUAL ESC" .................................................. .74

Read that... you can program the inside motor to run slower on turns, really helps the boat turn! It mixes the signal to each ESc with the rudder control. You can try it and bench test. Once it work right, then you program how much “mix” to use. You have to run the ship for that. The Flysky I don’t think mixes right for a boat. It’s made for 4 wheel steering, on a car. I got one and couldn’t make it work after many hours trying.

No resistor changes. Instead of running both channels from one Channel, just disconnect that parallel wire and run one of the opto inputs to your other reciever channel. Just add a wire!

[golfito]

I get it. Thanks for the tips. I did not know, I did not know it.
I hope to start tomorrow.
An oscilloscope would be ideal for checking the signals. But it is an instrument that I could never buy. About 20 years ago I used it a lot with cars.

[TRUCKPULL]

Craig

The 4pls futaba and the RX (R304SB T-FHSS 4-channel telemetry enabled receiver)
Will NOT work for the inside motor to run slower on turns
You need to reprogram the transmitter for that.(Futaba does not have a program worked out yet for the 4PLS radio)

The dual mixing on the 4PLS is for Truck crawler's with two motors and two ESC's
You have to step up to the next radio in the chain (Add about $200)

I asked Futaba about steering and reducing the inside motor to run slower on turns with the 4PLS.
Above is the answer they gave me.

Unless you have figured something out?

Larry

[CraigP]

Well damn! That’s the same road block I got to with my FlySky! I did find a little PCB that is tiny that you hook the rudder and throttle channels from your receiver to, and it provides two outputs for the left and right motor. It has a little pot on it to adjust the mix. Mix range is about 30-70%, adequate I think for most boats. Thanks for the info Larry

[CraigP]

I get it. Thanks for the tips. I did not know, I did not know it.
I hope to start tomorrow.
An oscilloscope would be ideal for checking the signals. But it is an instrument that I could never buy. About 20 years ago I used it a lot with cars.

It’s an essential piece of gear for me... sorry to hear getting one there is so difficult. Read Truckpull’s post above. That transmitter won’t mix like I said. I just saw the table of contents and figured it did, I was wrong! But I can help with that! I’ll post a part number/source for a PCB that does this function. Read my description above...

[TRUCKPULL]

Craig

In you last schematic, you show a Dual Channel OPTO - Isolator

Where can I get one?
Do you or can you build one for me?

My boat is wired about the same as you schematic except for the Isolator.

And that little PCB unit will be in my future also.

Larry

[golfito]

Thanks guys.
http://www.mtroniks.net/prod/RC-Accessories/ZGM.htm
You can get to serve yourself Larry.

[srislash]

Thanks guys.
http://www.mtroniks.net/prod/RC-Accessories/ZGM.htm
You can get to serve yourself Larry.
Oh man, I was going to go electronic parts shopping today but this will save a ton of time.

Larry, the channel mixer will take a little playing with and may slow the corners slightly but should be worth it. I had one made for me awhile back for the old Komodo build. I went to SAW running and someone with a larger boat needed the mixer more than I do I don’t have one in service now.

[CraigP]

Shawn and Larry, the module looks good! It has more in there and I like to keep the circuit at a minimum, to help eliminate potential problems. That shipping from EU can’t be cheap.

Look guys, this is such a simple thing for me, I have so many parts laying around and about 1/2hr to build each one. I will build each of you guys one if you just cover shipping. I would be honored to help you guys out. Let me know, I can get them in the mail Monday. I’m going to look up that stand-alone mixer and will post a thread to get it. I think Taiwan, about 1-1/2 week shipping. If you want one, then PM me your address.

[srislash]

Wow, that is so nice Craig. So you would need one to go inline(instead of Y) or one on each esc? And same question for the Mtroniks one since I ordered 10 of them. I know, impulsive!! I could cancel the order.

[CraigP]

Wow, that is so nice Craig. So you would need one to go inline(instead of Y) or one on each esc? And same question for the Mtroniks one since I ordered 10 of them. I know, impulsive!! I could cancel the order.

Well, the schematic is for a dual, but you bring up a good point. It would be beneficial in any boat, single or dual. So I'll make you two singles. They will have 3-terminal header strips, like the Receiver, just plug in-line. Remember, they are not required for Opto-Coupled ESC's, that have no BEC.

The sure fire way to tell if you should use one is to use your ohm meter and see if there is a connection from the ground on the signal cable for the ESC to the (-) battery side on the ESC. If its an open, you don't need it. Don't touch the metal tips on the Ohm Meter while measuring, it will read you body's conductivity and give you a confusing reading. This should read a complete open...

[CraigP]

Here's the link to the mixer. They built it for tanks and bots (much bigger market than boats) but will work on boats great. On first run, turn the pot all the way CCW. Do NOT force the pot past the stop! Just turn very lightly until it stops. These pots will not take any rough handling, like all micro, surface mount pots. If you need tighter turns, then start to turn back CW until you have it where you want it.

https://www.banggood.com/DasMikro-RC-Signal-Mixer-For-Tank-Dual-Bidirectinal-Motor-Control-p-1162275.html?rmmds=search&cur_warehouse=CN

[CraigP]

Wow, that is so nice Craig. So you would need one to go inline(instead of Y) or one on each esc? And same question for the Mtroniks one since I ordered 10 of them. I know, impulsive!! I could cancel the order.

Shawn, I'll send you a parts list, or email it. These are so simple to build, once you have these I think you can copy it no problem. Once you have your parts, then just build as needed!

[golfito]

Hello Craig, I can wait for the design of the mixer and build it. Some components can be found in my city. I could try with one to see how they work.

[golfito]

I want to tell him that I would like to have the construction scheme to make it in my house. As I do with the opto.

[golfito]

https://www.ebay.com/itm/DasMikro-RC-Signal-Mixer-For-Tank-Dual-Bidirectinal-Motor-Control-/172739479292?_ul=AR

[TRUCKPULL]

Here is a US supplier.

https://www.ebay.com/itm/Mtroniks-ZGM-Zero-Glitch-Module-Opto-Isolator/112604703004?hash=item1a37c3691c:g:3acAAOSw4GZZ5O-p

Larry

[CraigP]

Hello Craig, I can wait for the design of the mixer and build it. Some components can be found in my city. I could try with one to see how they work.

I don't think you can build the mixer. It is a small, microprocessor design. I'm building the optoisolator like you have. I won't have a schematic for the mixer.

[CraigP]

So you guys are good with the off-the-shelf isolator?

[golfito]

Ok, I had not understood correctly.
I could buy one by ebay later.

[golfito]

I am surprised that there are so many threads about erratic failures in RX / TX and not so much information about how to use an OPTO circuit in the RX / ESC.

[TRUCKPULL]

https://www.ebay.com/itm/DasMikro-RC-Signal-Mixer-For-Tank-Dual-Bidirectinal-Motor-Control-/172739479292?_ul=AR

Mix Ratio could be adjusted from 33% to 100%.

33% is the lowest setting.--- Not low enough.
We need below 10%.

Larry

[golfito]

Understood, thanks for the clarification Larry.

[CraigP]

Just to be clear, that’s 33% at 100% rudder input, to either side. I use D/R Reduction on my rudder, usually about 35%. I do that by making the crank arm larger on the rudder servo and use a smaller arm on the rudder. This brings the range to about 12% after the linkage ratio is in play.

I have one on my single Cat, where I just want some speed break heading into the corner. Only good for oval, right turn only. Let’s me run full throttle and allows me to concentrate on rudder only.

These things can be manipulated any way you want! It’s up to individuals to “see” their entire system, and bring each component into compliance to make that vision a reality.

[golfito]

http://www.mtroniks.net/prod/RC-Accessories/WTail.htm


http://www.mtroniks.net/prod/RC-Accessories/Progmixer.htm

[CraigP]

I don’t think the WTail Mixer will work. It has no adjustments that I could find in the manual.

The Progmixer has programming, but I’m not following the directions well. I would have to try one to see.

[CraigP]

I am surprised that there are so many threads about erratic failures in RX / TX and not so much information about how to use an OPTO circuit in the RX / ESC.


Yes, lots of unexplained failures. Many blame the ESCs. Probably, some ESC’s are more prone to signal glitching that others, I’m sure that’s a true statement. I’m beginning to think that all of my boats need isolation on LV ESC W/BEC. I don’t use ESC’s BEC for Rec/Servo power. Others have posted that some go into current limiting and that’s a big problem!

I’ve also been taking a closer look at the UBEC I got from OSE. It is not an isolated output. Has great current output. But it will carry the ground noise from ripple right into the Rec. A better choice is to use an isolated output, that is galvanically isolated from the power input, which is the noisy battery.

[CraigP]

Here’s my single opto-isolator. I’m going to put it in my DF29 Mono, that has a Turnigy 180A ESC W/BEC. Right now it’s running on that BEC, I need to get an external BEC.

[CraigP]

Here’s the dual isolator with the single. Golfito, this is more like what you need, according to your description. Saving this little baby for the dual build sometime this year!

These are using PS2501-1-L-A, a Panasonic version of the 4N25 that Golfito used. I used 0805 SM resistors and added a .01uF bypass cap, it was laying in front of me.

[golfito]

Excellent!
Very small size

[golfito]

I do not have smd resistors. Only 1 / 4w of wire.
I can gain space if I only use 220ohms. And not the sum of 220ohms + 33ohms to get close to the 249 ohms of the specifications.
But I'm afraid to degrade the circuit.

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[CraigP]

You can use 220 Ohm. I built mine with 232 ohms, I had them handy. Especially with a separate channel driving each isolator. You can gain space by mounting resistors vertically. Stick the lower lead straight into the hole, then bend the upper lead down, parallel with the resistor body. Then each resistor takes just two holes.

[golfito]

Great!

[ray schrauwen]

So you guys are good with the off-the-shelf isolator?

I suppose. Knowing now what you have found about ripple coming through, not so much.

Nice circuits. It's a skill I wish I was much better at.

[golfito]

I thought I could add some small capacitors between the + and - cable. C: 100mfx16v

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I have to make the bridges and the welds still.

[CraigP]

That’s way too much capacitance. It only requires .01uF, because the opto uses so little current. Large caps causes current spikes on power up, so you want to watch that. It could put the BEC’s in the ESC’s into current shutdown. The ceramic type cap, value .01-0.1uF, will be best. Sorry to tell you, but you want it right. The layout looks great!

[srislash]

Golfito... you are exhibiting some mad skills. You have a passion for this.

Craig I put in my cancellation of order request with Mtroniks so we shall see. I think at current moment I only would need to set up my BlownAway twin with isolation.
So I could use a dual isolator on that one.

Out of curiosity, would one still need to disconnect the red wire from the BEC equipped ESC’s when plugging in the isolator?

[golfito]

Thank you!
I think I have some ceramic capacitors out there ... the ones I used in brushed 540 engines.

Using the opto plate you must leave the red wires coming from the bec of the esc.

[CraigP]

Thank you!
I think I have some ceramic capacitors out there ... the ones I used in brushed 540 engines.

Using the opto plate you must leave the red wires coming from the bec of the esc.

Yes, each BEC inside each ESC powers up each opto-isolator. So the output signal from the opto-isolator is biased from the supply voltage from each ESC, and any noise is the same, so the ESC runs clean. The input is not wired to the signal (+) on the board, so no need to remove any red wires. The opto-isolator I built is wired like the Futaba servo wiring.

[CraigP]

Golfito... you are exhibiting some mad skills. You have a passion for this.

Craig I put in my cancellation of order request with Mtroniks so we shall see. I think at current moment I only would need to set up my BlownAway twin with isolation.
So I could use a dual isolator on that one.

Out of curiosity, would one still need to disconnect the red wire from the BEC equipped ESC’s when plugging in the isolator?

Shawn, email me your address. The one I built today is yours. I’ll let you know what the shipping is and PM you my PayPal info. Please read response to Golfito, you do not remove any red wires.

Note to Forum: I’m building this has a favor to Shawn, for no sale. He is just covering the shipping. Since the unit is not being sold, I figured this does not need to follow Forum rules for selling items. If I’m in error, then please let me know, thank you.

[golfito]

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The most similar and according to my friend google ... this one that says 104 would be correct. It is very, very tiny.

[CraigP]

You got it! Perfect size! It’s been so long since I’ve worked with thru-hole parts, brings back good memories...

[golfito]

I discovered that the yellow color means that it is 400v and the 104 equals 0.1mf ... what do you think Craig? I leave these or eliminate them directly ?.

[CraigP]

I discovered that the yellow color means that it is 400v and the 104 equals 0.1mf ... what do you think Craig? I leave these or eliminate them directly ?.

Good to go! :thumbup1:

[golfito]

Thank you!

[Jesse J]

Shawn, email me your address. The one I built today is yours. I’ll let you know what the shipping is and PM you my PayPal info. Please read response to Golfito, you do not remove any red wires.

Note to Forum: I’m building this has a favor to Shawn, for no sale. He is just covering the shipping. Since the unit is not being sold, I figured this does not need to follow Forum rules for selling items. If I’m in error, then please let me know, thank you.
Nice gesture Craig! So to put it simply, this unit is still recommended with the set up I attached in post #57?

[CraigP]

Yes Jesse, my simulation results is showing there is a need in all boats, unless you run an Opto-Coupled ESC, like the HV SW ESC’s. The isolation is already in there. I’m finding that sourcing the Receiver power from a BEC inside the ESC is a major step backwards from the days we all ran dedicated Rec batteries. There’s just too much noise at the ESC to make it the common ground. I’m changing my DF29 Mono, with a Turnigy 180 to using an ext. BEC. Then the int. BEC just provides power for the output of the isolator. I think all boat ESC’s should be opto-isolated.

The schematic on Post #64 is for a one input system, where the two motors will always run the same speed. A two input opto is for Chan mixing, with a Trans/Rec that has that capability. Then you will use two channels on the Rec, one for each motor. Also need 2 input for an Ext. Mixing board, such as those posted on this thread.

[golfito]

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

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https://hobbyking.com/es_es/turnigy-5a-8-40v-sbec-for-lipo.html

https://hobbyking.com/es_es/quanum-12v-5a-7-2-25-2v-dual-output-ubec.html

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

https://hobbyking.com/es_es/yep-20a-hv-2-12s-sbec-w-selectable-voltage-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-12v-5a-7-2-25-2v-dual-output-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?
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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.

[golfito]

Then for the simple opto I eliminate that resistance in parallel and I only leave connected the series resistance between pin 1 of the opto and the signal cable that goes to the RX.

[CraigP]

The resistance across pins 1 and 2 are to discharge the capacitance of the light emitting diode. Each diode needs its own discharge resistor. I guess I’m not following what “simple opto” means.

[golfito]

Sorry. Simple Opto I call it a single 4N35. And I tried to use one of these for each channel of the futaba rx.
In that modification
How would the resistor circuit for a single 4N35 be?
Resistance 1-2 is maintained.
So, I withdraw the series resistance between pin 1 and the signal cable ?.

[golfito]

I will put a resistance in parallel, both resistances of 249ohms. It will have half of its value in both and a resulting resistance of 249ohms.

[CraigP]

Sorry. Simple Opto I call it a single 4N35. And I tried to use one of these for each channel of the futaba rx.
In that modification
How would the resistor circuit for a single 4N35 be?
Resistance 1-2 is maintained.
So, I withdraw the series resistance between pin 1 and the signal cable ?.
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A dual opto is exactly the same as a single, only there’s two channels inside the device. Each channel must be wired the same. Treat each input diode the same. You can also wire it any way you want, this is just my circuit design.

[golfito]

https://www.youtube.com/watch?v=nqxkoz1t6E8&feature=youtu.be

My bad English is a limitation, excuse me.
I understand what dual opto and simple. I just wanted to have two simple opto circuits separately. And then use those two circuits to connect one in each ESC. In a RX of futaba with the dual function esc. Using the 2ch and the 4ch for the esc. Each with its opto circuit.

With the parallel, it reduced the resistance values by half. But just try it one at a time. And with the flysky rx.
*!** The real test will be with both teams together in the RX futaba. In dual mode esc. I hope not to damage any of the electronics by connecting both circuits and both ESCs.

[CraigP]

https://www.youtube.com/watch?v=nqxkoz1t6E8&feature=youtu.be

My bad English is a limitation, excuse me.
I understand what dual opto and simple. I just wanted to have two simple opto circuits separately. And then use those two circuits to connect one in each ESC. In a RX of futaba with the dual function esc. Using the 2ch and the 4ch for the esc. Each with its opto circuit.

With the parallel, it reduced the resistance values by half. But just try it one at a time. And with the flysky rx.
*!** The real test will be with both teams together in the RX futaba. In dual mode esc. I hope not to damage any of the electronics by connecting both circuits and both ESCs.

Are you having a problem when you test? It looks like it’s working in the video. I’m confused what the problem is...

[golfito]

It works. Both channels.
Only that it modifies the original circuit and the values of the resistances. To use it in the RX with "dual esc". But I have no confidence that he is correct with what he modifies. I can not prove it.


I'm going to build another opto board as its specifications and I will not use the dual esc function.
Very grateful for your help.

[CraigP]

Not sure why you’re reducing the resistance so much. This could cause a loading issue on the Rec. The Ohm Meter is lying to you. The circuit in operation does not “see” the combined resistance of 498 ohms. The led inside the device will only drop about 1.5 volts, so the parallel 249 Ohm resistor sees 1.5V across it. If your feeding 5V in from the Rec, then the series resistor “sees” 3.5V. So the Rec signal out has to deliver 20mA, well within its range. If you use your added up value of 498 ohms, which is wrong, the circuit would only pull 10mA from the Rec. So it actually pulls twice the current you think it’s using.

Not trying to be a problem, but I designed that circuit, then tested it on an electrical simulation program I use for my work. I then measured it on my DSO and posted pictures of that. The circuit is right! I’m open to debate about it if you can show me specific voltage/current information that is contrary to my stated facts. I think your just making a bunch of work for yourself and if you put that Rec into current limiting, you’ll be making more problems for your boat than the opto solves.

If I’m misunderstanding you because of the language barrier than I apologize. But you are showing half the resistance in the schematic you posted, I know that’s not the right way to go. You might want to try that with a Rec you don’t care about. Some the rec don’t have current limited outputs, so you could fry it. All in the name of science, I’ve blown piles of electronic parts up over the years!

[golfito]

I apologize for wasting your time. You have all the reason.
I used the concepts erroneously and realized that I must re-read the principles of the law of ohm. And read the data sheet. I wanted to have the circuit for a single 4n35 / ESC. Then use two of them for the dual esc. But I did not know how to solve it. It worked pure luck.

I'm going to buy the components again and build the circuit as specified. I saw the oscilloscope graphics. You did an awesome job.

I can erase the previous messages with my confusion if you want.
Thanks for the support.
Hernan

[CraigP]

I went back this AM and re-read your posts and they are misleading because those circuits won’t work like the scope shots I posted. I’m not asking to remove anything, because that’s not my place. I think you have to decide what’s best for the thread, and the many people that may read it. It seems we want to leave a path that is easy to follow. I would like to see other modelers build their own. So it would be nice to have a clean direction. Perhaps when you are done investigating I can drop in some clean schematics. There is interest in the single opto board, for single motor boats to break the ESC/Rec ground loop. There is also interest in a dual opto board, one with a single input connector driving both ESC opto’s. This mimics a Y Cable, only with isolation. The Opto Board is the “Y”. And lastly, a two input Opto Board where each input connector feeds one of the isolators, to be used for Trans/Rec packages that have Channel Mixing in the Transmitter or to come off an external mixing board, such as you found. That is my goal...

[srislash]

Craig, Mtroniks kindly cancelled my order so I’m not on the hook for 10 of those.

So I have a question, I have a couple of Spektrum RX’s (MR3000, dual outputs) that at some point along the way seemed to have one of the ESC outputs die. I’m trying to remember which setup they were in, lower voltage so ESC’s with BEC is coming to mind. Would the cause likely be that ground loop?
There were a number of issues when I started twins so I like you have a box of burnt stuff, lol ��

[CraigP]

Craig, Mtroniks kindly cancelled my order so I’m not on the hook for 10 of those.

So I have a question, I have a couple of Spektrum RX’s (MR3000, dual outputs) that at some point along the way seemed to have one of the ESC outputs die. I’m trying to remember which setup they were in, lower voltage so ESC’s with BEC is coming to mind. Would the cause likely be that ground loop?
There were a number of issues when I started twins so I like you have a box of burnt stuff, lol ��

Oh gee Shawn, thanks, LOL! Just what my wife wants to see! Kidding aside, yes, this ground loop can cause that failure. I can't believe it's taken me so long to see this... I did a poor job when I first laid out the electrical stuff in the first boat. Normally, I would spy that out from a mile away! I would love to see ALL ESC's come with Opto-Couplers, since I'm realizing (and the simulator is verifying) that a good ground can't be established at both, the Rec and the ESC. It has to be the Rec only. God only knows how bad the noise is in a twin, where the loops quadruple in magnitude. It's amazing that this stuff lives at all! It's only when I started the design process over again for my future twin build that I caught on to it...

I know many will say "it's good enough" and not pay attention. But at some point, the noise will give them some weirdness, and perhaps they spend time and effort redoing wires and placing things in others spots, never really solving the root problem.

[golfito]

Yes, excellent Craig.
I am interested in the three types of opto plates that I described.
Later I will start the construction of the circuit that you verified (simulates cable Y) As you do on the test plate (protoboard).
Greetings.

[srislash]

Oh gee Shawn, thanks, LOL! Just what my wife wants to see! Kidding aside, yes, this ground loop can cause that failure. I can't believe it's taken me so long to see this... I did a poor job when I first laid out the electrical stuff in the first boat. Normally, I would spy that out from a mile away! I would love to see ALL ESC's come with Opto-Couplers, since I'm realizing (and the simulator is verifying) that a good ground can't be established at both, the Rec and the ESC. It has to be the Rec only. God only knows how bad the noise is in a twin, where the loops quadruple in magnitude. It's amazing that this stuff lives at all! It's only when I started the design process over again for my future twin build that I caught on to it...

I know many will say "it's good enough" and not pay attention. But at some point, the noise will give them some weirdness, and perhaps they spend time and effort redoing wires and placing things in others spots, never really solving the root problem.

First off I feel for the wife, well I understand anyway.

Yes now we need to really prove this. There have been many unexplained issues over the last few years. Spektrum radios being blamed perhaps when it was something like this. Each ESC could be more sensitive than the next. As you said perhaps a over current shutdown in the rx(Rec).
Many (ok maybe just a few) have had the boat go out round a course and have a shutdown. Just over and over again. The fix?? A new Futaba radio as I recall. So someone should find out if Spektrum does undead have a Rx shutdown built in. I myself have never had an issue with Spektrum other than antenna things. So I always wondered what was up with these others. Perhaps this is it!!!

[golfito]

Very impressive. Thank you very much sir!

[srislash]

Nice work Craig. Really appreciate the knowledge and wisdom.

[TRUCKPULL]

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

[CraigP]

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!

[ray schrauwen]

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

[CraigP]

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...

[CraigP]

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.

[CraigP]

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.

[CraigP]

Here is the 1 Input, 2 Motor Opto Board...

[CraigP]

Here is the 2 Input, 2 Motor Opto Board...

[golfito]

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

[CraigP]

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?

[golfito]

Craig,
I just tried it on the breadboard and the ESC does not work. TX / RX turnigy / flysky, optp 4N35, 1k resistors
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[golfito]

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

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[golfito]

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https://www.youtube.com/watch?v=ZnUJe97xK30&feature=youtu.be

[CraigP]

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!

[CraigP]

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

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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!

[golfito]

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.

[CraigP]

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!

[golfito]

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.

[CraigP]

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

[golfito]

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

[golfito]

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[golfito]

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[golfito]

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=e9RX46Xdvvk&feature=youtu.be
https://www.youtube.com/watch?v=8tLBYyz6IGs&feature=youtu.be

[CraigP]

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.

[golfito]

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

[Jamey]

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. :confused2:

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!

[CraigP]

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.

[Jamey]

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

[Jesse J]

It would be best to keep this a twin motor thread, since there seems to be a lot more to consider working with twins than I thought.
Thanks!
Craig, I'm using for now, a pair of those opto gadgets posted on page 2 or 3. Seems to be working.

[golfito]

Opto_Board_2_Input_2_Motor_Power_Schematic.pdf #160
I could find only two ps2501-1. Armed as the PDF of post 160.
Working correctly for the flysky GT3B radios, it was running 3pv4 / 4pls and an old spektrum DX3s.
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[CraigP]

That looks good Golfito! I got about 80 of the PS2501-1 from an old project I did. They are still available. Maybe you can go over the spec sheet and find an alternative.

[MG1234]

So you guys are 5 steps above my pay grade regarding cap banks so I’ll jump in here and ask ,I read that I’m supposed to leave the stock cap bank when adding a set of caps but I just don’t have the room on a twin fighter cat ,I have 2 HW 180 amp ESC,ran them last year on 6 s each,they gave me a little trouble at the end of the season ,sent the boat up on the shore full throttle,it’s happened before with other boats using HW ESC running them hard,so I want to add a cap bank but need to remove the stock one ,I’ll also add a BEC, I read that that helps theses ESC also,I was going to install the castle creations capacitor pack that has the 4 caps and 2 posts to connect to,your opinion please ,my other boats have room to leave the stock caps in place ,I’ll be adding the extra caps there also,thank you,

[CraigP]

Sorry to hear about the troubles, nobody likes seeing their pride and joy heading toward the shore with a mind of its own! The problem sounds more to do with “glitching” of either the ESC or Receiver. A glitch is a term in electrical systems like the word “bug”, which means a critical system (usually the microprocessor in either the ESC or Rec) gets an electrical disturbance, normally on the ground of the electrical system. If you read through this post, you’ll see that some of us have started using Opto Boards to keep the ground clean between the ESC and Rec.

Also note that the BEC’s internal to many ESC’s (like the HW ESC) can shut down due to high servo current draws or electrical noise “glitching” the over current detection in the switching regulator. Bottom line, I don’t use the internal BEC and always install and external unit that can supply at least 3A continuous and 5A surge. ESC’s often state their BEC is in that range, but there are many reports of problems.

There is an unintentional ground loop formed which has been discussed earlier in this thread. I’m pretty sure you’ve been a victim of that. It’s NOT an easy topic! There are schematics posted on this thread that should give you some ideas to get it just so...

[MG1234]

Thank you for explaining the glitch,I knew it had something to do with pushing those HW ESC too hard,I’ll install external bec,now I just need to know if I can remove the existing cap bank to install an extra ,or maybe only because there is no other way ,installing the extra cap bank with extention wires maybe 3” long max,it’s really tight inside this boat ,anyone?..thanks ,

[srislash]

As close to the ESC as possible is the rule. If you can replace the old ones so be it.

Any chance you can marry the negative wires as shown previously in the thread?

It has been a given that any of the HW ESC’s would cook their BEC on 6s. At least it was on the old ones.
It is just to hard to reduce voltage and current that much in such a small space. There is no cooling provision for an onboard BEC either.

[MG1234]

Thank you ,I’ll look again at that diagram and see if I want to give it a try ,thanks again ,

[CraigP]

Switching regulators running at 200Khz and above won’t give you a heating issue. Most of these external BECs I’ve checked out are that speed and above. But they do emit noise! So they should be at least 2-3” away from your Rec and that goes for the inlet power wire as well. I use the type that have a metal shield over the noise emitting elements on the circuit board. They usually refer to those as “fully shielded”.

[MG1234]

I’m going to use a castle BEC ,just because it’s all I know ,thanks ,

[dasboata]

THT good reading

[CraigP]

Response to Jesse: Some receivers don't like them, but I've had good results with all of mine. My dual hydro has a silky smooth throttle response (no sudden lurches) and it cleaned up a servo mixer I was using for the rudder/starboard ESC. I slowed it down slightly on right turns. The only way I could get it to really dig out on a turn!

[CraigP]

Thanks Craig, I think I'll do something similar, but bring the batteries in series. I'd like them to get drawn down together. This may require separating the cap banks completely. I'll post a picture when I get it wired.
Jesse, you can make it a 2-plate system, all caps in parallel. Two sets of batt leads coming in, and two sets of ESC leads going out. Batt leads to cap bank can be longer, but cap bank to ESC needs to be short as possible. Bring one of the batt leads into one side of the cap bank, the other on the opposite side. Both ESC lead sets come from the middle of the cap bank. This forces even current sharing among the capacitors. So it looks physically like a T with batt leads coming from each side and the ESC leads both coming from the middle. I hope that helps you... oh, and all caps MUST be the same type..