Common caps for two escs?

[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.Inked25442832_1771890443112689_7268919452023559472_n_LI.jpg

[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 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

[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/merchan...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.