Hooking up twins

[dasboata]

so I am running twin TP 4060/1950 KV on 6 S , with water cooled castle XLX, my RX keeps cutting out, looking at the log it shows the BEC voltage is dropping to 2.7 and lower, the logging also shows the ESC rebooting during these runs the ESC does show hi temp, i have changed radios, I do have the red wire disconnect , I see guys running 2000 KV on 6 S ?? Im willing to buy new 1650 KV motor if that's the problem, I do have the logging saved if , I could send someone the zip files thanks guys PS the 1st 2 pics are port side

[jkflow]

Trying to reconcile some answers.
You need to run both ESC on the same channel, using a Y-cable.
You must remove 1 middle pin (positive) either from the y-cable or the ESC wire. Yes, that is causing your issue, see below.
You will effectively only use one BEC, which is what you need to do. I typically do not clip wires by default, you can lift a nose on those pins and slide back the contact. Heat shrink and you are done.
Once it's connected in 'y' you have to do the throttle range adjust and both ESC will see the identical signal.

I wouldn't recommend running this to 2 different channels and using mix mode or similar. Will probably work but over time things will drift slightly. Honestly never tried it but you avoid all the guessing with a y-cable.
You would still have to remove one positive 'middle' wire if you do this.
All positives and negatives are on their own bus inside teh receiver.

Why do they stop working?
You have 2 BEC connected, and they will never be the same, just based in real life wiring and subtle differences. Eventually they will start fighting each other and start to oscillate on the output voltage, eventually they will overload each other and the voltage will collapse. This can draw the max possible amp and might smokle wires. Even though they are separate circuits inside the ESC, they are truly not. Under high load, the ESC/BEC might drop more than the other, even if the BEC load is the same. One might sag just a little and start of this cycle of oscillation and ultimately cause the voltage drop. Most likely you do not see any oscillation on the logger, you will need a much higher sampling rate.
Note: I hope you are aware that you can zoom into your data and just look at the actual event or what is leading into it.

Other issues exist and people report just having the ground wires connected can cause ESC's to go haywire, but that seems to be a random event. Self-made opto isolation always has risks, no comment on what might have gone wrong above, would have to see the circuit design.
If you do use an external battery, you have to remove both 'middle' wires, or again you will see potential chaos.

[dasboata]

Trying to reconcile some answers.
You need to run both ESC on the same channel, using a Y-cable.
You must remove 1 middle pin (positive) either from the y-cable or the ESC wire. Yes, that is causing your issue, see below.
You will effectively only use one BEC, which is what you need to do. I typically do not clip wires by default, you can lift a nose on those pins and slide back the contact. Heat shrink and you are done.
Once it's connected in 'y' you have to do the throttle range adjust and both ESC will see the identical signal.

I wouldn't recommend running this to 2 different channels and using mix mode or similar. Will probably work but over time things will drift slightly. Honestly never tried it but you avoid all the guessing with a y-cable.
You would still have to remove one positive 'middle' wire if you do this.
All positives and negatives are on their own bus inside teh receiver.

Why do they stop working?
You have 2 BEC connected, and they will never be the same, just based in real life wiring and subtle differences. Eventually they will start fighting each other and start to oscillate on the output voltage, eventually they will overload each other and the voltage will collapse. This can draw the max possible amp and might smokle wires. Even though they are separate circuits inside the ESC, they are truly not. Under high load, the ESC/BEC might drop more than the other, even if the BEC load is the same. One might sag just a little and start of this cycle of oscillation and ultimately cause the voltage drop. Most likely you do not see any oscillation on the logger, you will need a much higher sampling rate.
Note: I hope you are aware that you can zoom into your data and just look at the actual event or what is leading into it.

Other issues exist and people report just having the ground wires connected can cause ESC's to go haywire, but that seems to be a random event. Self-made opto isolation always has risks, no comment on what might have gone wrong above, would have to see the circuit design.
If you do use an external battery, you have to remove both 'middle' wires, or again you will see potential chaos.

as stated above I do have one red wire disconnected by pulling the pin out , I did try on the bench removing the center red wire off the Y connector going in to the RX , instead of removing the 2 on the Y end , using a external LIFE battery , it did not work and the plastic plug showed signs of melting ? I'm going to make a new Y connector and try that, but still want to hear more opinions I can send the zip files of the data thanks man

[jkflow]

Ok, yes you are making a simple error, but essentially all the above applies.

The Y-cable connects both ESC in parallel and has a single leg going to the receiver. You essentially did NOT remove the plus wire from 1 ESC.

You actually have to remove 2 pins minimum if you are using an external battery, either in the Y-harness or each ESC leg.

Removing the center pin on the single Y-end does not work, You are still shorting out the BECs of the 2 ESC. You have only broken the leg to the receiver, but still shorting the ESC power lines.

You have to break the ESC to ESC leg, can either be done by removing a socket on the ESC connector (easy) or by cutting a wire in your Y-harness.
Removing the pins in the y-cable is almost impossible, removing the sockets on the ESC is very easy.

I can draw a quick picture if needed.

[jkflow]

You have done this, black line is the break. See how the 2 ESC are still connected inside the Y-cable?

Need to break 2 legs.Clipboard02.jpg

[dasboata]

You have done this, black line is the break. See how the 2 ESC are still connected inside the Y-cable?

Need to break 2 legs.[ATTACH=CONFIG]173869[/ATTACH]

what the difference ?

[jkflow]

The difference, you have never removed the ESC to ESC red wire. Still in place, all you have done is break the connection to the receiver. That does nothing to your original problem.
It matters where you break the chain. You can't do it in the end connecting to the receiver, has to be broken prior to avoid having the BEC in parallel.

[jkflow]

Do this on one of your ESC wires if you want to use the BEC function. Very easy to revert if needed. No cutting needed.
If you want to use an external battery, you have to do it on both or cut the wire going to the receiver, like you did.

https://www.youtube.com/watch?v=clNvfjhMQ5w&t=61s

[dasboata]

The difference, you have never removed the ESC to ESC red wire. Still in place, all you have done is break the connection to the receiver. That does nothing to your original problem.
It matters where you break the chain. You can't do it in the end connecting to the receiver, has to be broken prior to avoid having the BEC in parallel.

oh ok thanks Ill try that, I orders 2- 1650 motors , I'm going to run a external life 6.6 and disconnect both red wire out of the ESC & give that a try thanks man

[fweasel]

Chris, de-pin the red wires on both legs of the Y-harness that connect to the ESC's, not the single plug that goes to the receiver. That stops the BEC voltage from both ESC's from going anywhere. Then plug your LiFe battery into an unused channel on the receiver.

For the record, the larger Castle ESC's usually have high current BEC's to drive big servo's in offroad RC's. If you screw up the wiring, the problems will be bigger, faster, hotter because of the high current BEC.

[dasboata]

Chris, de-pin the red wires on both legs of the Y-harness that connect to the ESC's, not the single plug that goes to the receiver. That stops the BEC voltage from both ESC's from going anywhere. Then plug your LiFe battery into an unused channel on the receiver.

For the record, the larger Castle ESC's usually have high current BEC's to drive big servo's in offroad RC's. If you screw up the wiring, the problems will be bigger, faster, hotter because of the high current BEC.

Thanks Ryan that's the route, I'm going to go . I cant do it on the Y harness because those are males, & I cant get to the pin releases, but I will do it on the ESC , I hope I did not screw it up do already ,

[T.S.Davis]

That's the right way Chris. Just tape those down with some electrical tape or something.

I asked "when" it was cutting out because I thought maybe you were hitting the amp limiter. Done that multiple times myself. Doesn't sound like that's what is happening. Two BEC's fighting each other could do it. Or one BEC fighting a receiver pack. The LiFe should run your system nicely.

[TRUCKPULL]

Chris

I use the connection harness on the right side of the picture to disconnect the red wire (it makes it a lot easer to connect it at a later time for programing)

I also use two types of duel connection harness - one for duel servos, and one for duel ESC's

Larry

[dasboata]

That's the right way Chris. Just tape those down with some electrical tape or something.

I asked "when" it was cutting out because I thought maybe you were hitting the amp limiter. Done that multiple times myself. Doesn't sound like that's what is happening. Two BEC's fighting each other could do it. Or one BEC fighting a receiver pack. The LiFe should run your system nicely.

It was only pulling 70-80 amp when cutting out Terry ,,,I'm going to put the 1950 KV back in,, but I have some XLX2 on order that I will use instead

[dasboata]

I don't see a difference in the 2-Y connectors , so correct me if I'm wrong you still use the y connector , but you use the 2- wires in the right with it ?