Limitless Remotely switch ON/OFF Hobbywing Xerun ESC

[nathanlow]

Hi everyone!

Wondering if anyone has any idea how to remotely switch ON and OFF the Hobbywing XR8 G2S esc.

Red power button: Quick press to turn ON, Long press to switch OFF.

Using NB4 remote.
I don't think those LED switching boards (Connect to CH3/4 of receiver) can work on this Power switch.

Any ideas?

Not to be used for Limitless, but for my 1/8 GT race car.

Maybe i will share the reasons for this.
During race, we would want to highest possible charge and capacity of the lipos at the start of the race.

Unfortunately, incidents happen during line up, and cars are static waiting for others to get ready, and it can take up to 5 or 10 minutes.
High flow fans that sucks up amps doesn't help either.

And drivers are standing 3 floors up from where the cars are.
Some drivers will have someone switching it off for them. Most do not.

Thanks for any input.

 

[razorrc]

Sounds impossible without a separate receiver battery (like a nitro car). How are you going to turn on the car if the receiver isn't powered?

 

[nathanlow]

Sounds impossible without a separate receiver battery (like a nitro car). How are you going to turn on the car if the receiver isn't powered?

Maybe power it from lipo balance leads?
Main issue is the switching signal (short press, long press)

 

[RC-Dude]

I was breeding horses a while back. It was a breed that would need less and less food. When I finally got the main stallion so far that he did not need to eat anymore he unfortunately died. That could have been such a great venture. Was such a cool idea with climate and so.
Seems like this idea is a bit similar. Not sure, maybe I'm wrong.

 

[nathanlow]

Maybe i will share the reasons for this.
During race, we would want to highest possible charge and capacity of the lipos at the start of the race.

Unfortunately, incidents happen during line up, and cars are static waiting for others to get ready, and it can take up to 5 or 10 minutes.
High flow fans that sucks up amps doesn't help either.

And drivers are standing 3 floors up from where the cars are.
Some drivers will have someone switching it off for them. Most do not.

 

[rotauq]

Signal from the remote is not a powered relay. You would have to replace the power button with something like a rc kill switch (google it)
The led switching board you refer to could work as wel. The power button only enables the bec and has to deal with only a couple of amps.

When you directly power the receiver (some nb4 receivers take up to 12v), make sure you don't feed the red cable from the esc into the receiver or you will likely ruin your bec. You can use an extention cable and cut the red wire there if you don't want to cut the one on your esc.

 

[nathanlow]

Signal from the remote is not a powered relay. You would have to replace the power button with something like a rc kill switch (google it)
The led switching board you refer to could work as wel. The power button only enables the bec and has to deal with only a couple of amps.

When you directly power the receiver (some nb4 receivers take up to 12v), make sure you don't feed the red cable from the esc into the receiver or you will likely ruin your bec. You can use an extention cable and cut the red wire there if you don't want to cut the one on your esc.

Thanks for reply @rotauq
The Hobbywing switch is not a simple switch as it has a MCU on the pcb. It also houses the SET button. My guess is that it send PWM signal to the ESC.
As for external power to receiver, yup, i have done external BEC before(ESC LIPO leads>SBEC>RX 7,4V)
Definately need to remove the Power wire from ESC leads, leaving only the PWM signal wire.


Anyhoooo..seems like a dead end

 

[rotauq]

Thanks for reply @rotauq
The Hobbywing switch is not a simple switch as it has a MCU on the pcb. It also houses the SET button. My guess is that it send PWM signal to the ESC.
As for external power to receiver, yup, i have done external BEC before(ESC LIPO leads>SBEC>RX 7,4V)
Definately need to remove the Power wire from ESC leads, leaving only the PWM signal wire.


Anyhoooo..seems like a dead end

I am not sure about the Xerun version, but on any (ezrun)hobbywing/castle i was able to turn them on and off with a switch on red/black

When off, a quick press or continious on signal will work just fine.
When on, (and a continues signal is still running) turning it off and on again should power it off.

You could just try by manually hotwiring the black and red. I think you can even leave the power button on there if you would require the set function.

Other option is to disassemble the button and hotwire the botton instead of the wires

 

[Dan B.]

Maybe i will share the reasons for this.
During race, we would want to highest possible charge and capacity of the lipos at the start of the race.

Unfortunately, incidents happen during line up, and cars are static waiting for others to get ready, and it can take up to 5 or 10 minutes.
High flow fans that sucks up amps doesn't help either.

And drivers are standing 3 floors up from where the cars are.
Some drivers will have someone switching it off for them. Most do not.

You could easily switch your fans on/off with the proper assignment and setup of your radio. That would help a bit.

 

[Moonstonemike]

You could easily switch your fans on/off with the proper assignment and setup of your radio. That would help a bit.

Or get really intense and make a thermostat relay that cycles your fans based on temperature thresholds. This way your also not losing power until it starts getting to hot.

 

[dure16]

Or get really intense and make a thermostat relay that cycles your fans based on temperature thresholds. This way your also not losing power until it starts getting to hot.

Paging @MMoelmann

 

[LipoShirly]

I have not used this one, but there are cheap wireless switch units available that will work in "momentary" mode, similar to the PB switch on the ESC. You would have to hack into the existing one to do the interface, My only worry would be leading the final lap and having the unit glitch...

Amazon Wireless Switch

You could easily switch your fans on/off with the proper assignment and setup of your radio.

This idea is a little more fail safe

Amazon RC Switch

 

[SrC]

Is there a real reason to do this in the first place?
Short of doing it as an excercise, makes no sense to even need Remote power Up or Off at the radio. This is not like a Nitro rig with a remote Radio 'Kill Switch".
I wouldn't bother. I see NO advantage or benefit.
The power should always be powered Off in a deliberate fashion. By the ESC switch. Then the Lipos disconnected immediately, by hand, anyway.

The Safest way to operate any Electric RC car.
If it was a thing, ESC's and Radio would have done this already.
Not from the Radio.

 

[slick2500]

You could easily switch your fans on/off with the proper assignment and setup of your radio. That would help a bit.

This sounds like a much simpler solution to me.

 

[Moonstonemike]

This idea is a little more fail safe

Amazon RC Switch

Ive seen those switches before used for led lights. Can you explain what the difference is between using a switch like that and just just running off a 3rd channel?

 

[Yonic]

My Hobbywing XR10 have remote power OFF, but not on:

Remote Off
Option 1: Enabled
Users can simply push and hold the brake trigger for 6 seconds. This option allows the user to turn off the ESC without pushing the ON/OFF button switch

My XE8 G2s doesn't have this though. and as noted.. it's the "turning on" which is more problematic

 

[dure16]

Ive seen those switches before used for led lights. Can you explain what the difference is between using a switch like that and just just running off a 3rd channel?

The switch is required for the transmitter on/off signaling to work properly.

Plugging the fan into a 3rd channel without an additional switch will result in the fan being on all of the time.

 

[LipoShirly]

Ive seen those switches before used for led lights. Can you explain what the difference is between using a switch like that and just just running off a 3rd channel?

The 3rd channel operates just like the first 2, its a PWM signal that changes duty cycle based on position of some input device , like the throttle or steering. The 3rd channel on my Dumbo RC transmitter is a switch, either ON or OFF, but that doesn't mean the receiver output is ON or OFF, as mentioned its still a PWM signal, it just goes from 0 to 100% in a single push of the button. If you had an LED hooked directly to the channel you would see the LED ON but not bright when the channel was ON, and the LED would dim slightly when the channel was turned OFF. The RC switch I pointed to has a device on board that decodes the PWM signal and then opens or closes a switch accordingly, just put this switch in series with your load (LEDs) . Not a very good explanation, I'll look for a good You Tube video and post it

 

[RC-Dude]

Throwing a brick towards the car might work to shut off. But turning on with brick throwing - don't think that is going to work so well. Aiming practice takes away drive time. And I think it's a bit much to carry that brick around. And if you miss the first time you have to walk and fetch the brick. Don't think bricks are such a good solution.

Maybe one of those keychains where you clap and find your lost keys could work. Just connect the electrical pulse to the on/off of a sound switch. Perhaps a keychain where you can whistle to find your key would be better. That way you don't have to put the transmitter on the floor.

It's important to be good in clear thinking when it comes to these things. Hope nobody is offended by me thinking out of the box.

 

[Jerold]

Is there a real reason to do this in the first place?

This is a good question. What will you get from it or why do you need to do this?

Putting that question aside, I belive you will need to
1. Determine if the Hobby Wing PB is simply a switch.
2. Power the RX from a source other than your ESC, which means a bypass harness.
3. Add what ever circuitry you need to operate the switch from a channel.
4. Verify the assumptions

Is this more than a switch?
Looking at the switch (Xerun XR8) it looks like 4 wires. 2 red, white and a black. It also has two buttons! So there's a chance it's just a switch.

Looking HW website, it has several versions of the power lead and some of them are simple SPST slide switches. Which implies there is a "master switch" at least for some of the ESCs.
https://www.hobbywingdirect.com/products/esc-switch?variant=17845690500

So this depends a bit on which Xerun ESC you have.

Into theory/guessing land here. If the PB is a momentary switch, then it may have some sort of glitch filter that requires a "long press". Meaning that connecting the two leads turns it on, but connecting and waiting is required to turn it off. Which makes sense because if the switch gets bumped it could turn off too easily. It's only a spring and a contact so a hard landing might turn off your ESC.

If that is true, then a quick short of the leads would turn it on (assuming it has power) and a long short would turn it off and a PB, switch or something else doesn't matter as long as the voltage on the other end is correct. There is a bunch of logic in the ESC that is figuring out when to "turn on" the ESC. The reality is that it's on but the micros are not. So it's probably not really off (no current draw) when it's "off".

To figure this out I would see if you can Ohm out the switch and determine the behavior. Ideally you see button push = 0Ω and button not pushed = ∞Ω.

Lets assume that's true, the next thing to do would be to probe the voltage on the switch. One side will have some voltage and the other side is most likely 0V. For the sake of argument lets call it +V. If that's the case then you can pull the ground side to +V to start the ESC and pull and hold it 5V to stop it.

What? You're connecting power and ground, that's bad?
Not really if it's what I think it is. It's likely two IOs. IO's can float and be pulled low by a resistor, which makes it a pseudo ground. If you ohm it out from the PB to ground you should see some resistance, i.e. it won't be 0Ω.

My guess is that it would look something like this. Confirm this before and make your own analysis before you implement a new circuit.

Custom Harness
Bypassing the ESC power is probably the easiest part here. You will need an external BEC and remove the power wire from ESC-RX cable. Leaving the ground wire technically creates a ground loop (which can be bad) but it's low speed and very noisy, so it's probably not going to do anything as nothing has a solid ground reference anyway. Leaving it makes the modification simpler because you just pop the pin on each side and snip it off, that's all.

On/Off Circuit
This is the hard part. You will need something that turns it on and off. Basically do two things pulse the 0V side for the time Ton and the time Toff. What that time is I don't know it might be a bit of an experiment?

As someone mentioned there are some LED controllers out there. Maybe just have it work on a remote button that sends a signal the length of you button press.

But again You need to make sure the voltages match up, there are no shorts.

Assumptions
We made a lot of them and they are usually not correct.

There are no guarantees that any of this will work. You will need to verify everything to make sure you don't burn something up. Modify this scheme as the information comes through.

Best of luck.