Rear steer glitching whole truck

[Flippinrigs]

Hey guys, I have a custom tube chassis that's kinda based off of a wraith, it's got a wraith tranny and axles but has bomber trailing arms. Anyways, onto the question itself. I just added rear steer to it and its acting kinda funny. For electronics I'm running a castle mamba x with a Holmes puller pro 3500. The front servo is a promodeler 420. The rear servo is just a cheap one so I could try it out. The remote is just an old cheap flysky gt3b. I had to pick up a heyok 2 channel rear steer adapter thing. Running on 2s and 3s. Anyways, after adding it it works good, rear servo is a little slow because it's just a low torque cheapo. But after crawling for a few minutes it's like the whole thing shuts down. It wont do anything except turn slightly, then itll come back to life for another 20 to 30 seconds and do it again. Sometimes once it wakes back up itll go full throttle for a few seconds and shut off again. Any idea on what could be causing this? Sorry for the lengthy post but wanted to explain it the best I could.

[micro racer]

Sounds like the whole system is pulling too much current and needs a BEC. Unplug the one servo, drive it around and see if it glitches. If the glitching stops, check again with only the other servo plugged in. Basically, if both servos work fine on their own but glitch when together, you need a BEC.

[Flippinrigs]

Originally Posted by micro racer

Sounds like the whole system is pulling too much current and needs a BEC. Unplug the one servo, drive it around and see if it glitches. If the glitching stops, check again with only the other servo plugged in. Basically, if both servos work fine on their own but glitch when together, you need a BEC.

Would it be just a bec for 1 servo? The esc has an 8.4 volt bec. I'm not really too familiar with the whole bec thing. I've been into the hobby for a few years now but have just recently started getting serious with it

[micro racer]

A BEC provides a set voltage up to a certain amperage. Most stock speed control's have their internal BEC set to 6V or less, and can usually output about 2-3 amps. An external BEC, like the original 10 amp from Castle, or their newer 14A and 20A models, have an adjustable voltage and can output a current up to what it is stated in the name itself.

If your servos pull more current than the BEC (internal or external) can provide, the system will brown out. Some servos pull so much power that they'll brown out the sytem just while trying to center, which often makes it look like there is something wrong with the radio

*If your ESC is actually set to 8.4V, you may have toasted a servo* This is pretty unlikely, as it shouldn't have been set at 8.4V from the factory and I doubt you've manually changed any settings.

An external BEC will plug into the receiver and power both servos. The internal BEC in the ESC needs to be disconnected by removing the red wire from the servo connector, otherwise you have to different voltage sources and that can cause some weird problems.

[Flippinrigs]

Originally Posted by micro racer

An external BEC will plug into the receiver and power both servos. The internal BEC in the ESC needs to be disconnected by removing the red wire from the servo connector, otherwise you have to different voltage sources and that can cause some weird problems.

So to disconnect the bec in the esc I need to rid of the red wire on the servo leads? And would an external bec at 8.4 run them better than the internal at 8.4? Or how does that work? Sorry for the newb questions lol

[micro racer]

Yep, but I would just remove the red wire from the connector and heatshrink it back to the wire, instead of cutting it off. That way you could reinstall it into another truck without a BEC, or program it like on a Castle ESC.

An external BEC will always have a higher amp limit than the ESC's internal BEC (otherwise there's no point in the first place), therefore you will be able to run stronger servos, brighter/more powerful lights, and generally more accessories with an external BEC installed. An additional bonus is that many BEC's (definitely all Castle BECs, which I would recommend) have an adjustable voltage. So if you don't have HV servos, you can set the BEC to 6.0V; if you have "standard" HV servos you can set it to 7.4V, and true HV servos can be set to 8.4V.

*Again, your Mamba X internal BEC is probably not at 8.4V. Stock settings are like 5.5V or 6.0V. With an external BEC, make sure that your receiver itself, both servos, and anything else that is plugged in to the receiver (and thus getting powered by the BEC) is capable of running at whatever voltage you set it to.*

(No problem!)

[Steve g]

I've had issues with cheap servos causing the glitching. Could not have the reciever and the servo on the same bec. It wasn't that the bec was underpowered or over worked, it was something with the servo interfering with the reciever. So you might want to keep your receiver powered by the esc bec, and use an external bec for just the servos. Should wire it that way anyways, this way you can safely up the voltage for the servos and not have to worry if your reciever is rated for it. Holmes hobbies makes a plug n play connector to wire it this way with no soldering or cutting wires, if you need.

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[Flippinrigs]

Originally Posted by Steve g

I've had issues with cheap servos causing the glitching. Could not have the reciever and the servo on the same bec. It wasn't that the bec was underpowered or over worked, it was something with the servo interfering with the reciever. So you might want to keep your receiver powered by the esc bec, and use an external bec for just the servos. Should wire it that way anyways, this way you can safely up the voltage for the servos and not have to worry if your reciever is rated for it. Holmes hobbies makes a plug n play connector to wire it this way with no soldering or cutting wires, if you need.

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I have a heyok plug and play bec. Will that work?

[Steve g]

The no brainer bec? Yes that is perfect. It'll power just the servo and you leave your esc wire alone to still power the reciever. Heyok makes nice stuff too.

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[Flippinrigs]

Originally Posted by Steve g

The no brainer bec? Yes that is perfect. It'll power just the servo and you leave your esc wire alone to still power the reciever. Heyok makes nice stuff too.

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So which servo should I plug into the bec?

[Steve g]

Would do the rear one, seems to be the one giving you issues. What kind of servo is it? The powerhd 23kg wp was the one giving me issues.

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[Flippinrigs]

Originally Posted by Steve g

Would do the rear one, seems to be the one giving you issues. What kind of servo is it? The powerhd 23kg wp was the one giving me issues.

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I have no idea, just some no name 20 dollar servo from Ebay I think lol, it was just an old one i had laying around. My promodeler doesn't give me any issues, the truck ran flawlessly with just it

[Flippinrigs]

Originally Posted by Steve g

Would do the rear one, seems to be the one giving you issues. What kind of servo is it? The powerhd 23kg wp was the one giving me issues.

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So, I tried playing with it, haven't found my no brainer bec yet so I havent tried that. But I unhooked the rear servo and now everything is exactly the same as before but yet it still goes in and out. Except now my notor is extremely hot. That never happened before. Now I'm wondering could it be something to do with my motor? I hope not, it's only a few months old and it's like 130 dollars lol

[Steve g]

Well that's not good. Almost seems as if the rx went bad, but I don't think it would cause the motor to get hot. Maybe something happened with the esc. Do you happen to have an extra rx or esc to test out? There's no drive line binding right?

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[Flippinrigs]

Originally Posted by Steve g

Well that's not good. Almost seems as if the rx went bad, but I don't think it would cause the motor to get hot. Maybe something happened with the esc. Do you happen to have an extra rx or esc to test out? There's no drive line binding right?

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I tested it out with a different rx/tx and it runs fine without the rear steer hooked up (didnt try with rear steer hooked up) but my motor is making an awful grinding noise and after just 2 minutes of being ran its hotter than it should be. Hotter than it ever got after a couple hours of abuse. Theres no drive line binding, it's all be recently gone through

[Ditchrat]

Originally Posted by Flippinrigs

I tested it out with a different rx/tx and it runs fine without the rear steer hooked up (didnt try with rear steer hooked up) but my motor is making an awful grinding noise and after just 2 minutes of being ran its hotter than it should be. Hotter than it ever got after a couple hours of abuse. Theres no drive line binding, it's all be recently gone through

That sounds like a hung up brush or a comm that had a plate come loose. It would also explain your glitching and reset.


Situations like that draw high amps which might send the esc in to shut down.


You might try disconnecting the motor, then trying your original rear steer set up. See if the glitching goes away.


the other thing is check your end points, I have had cheap servos do all types of wonky things when they over heat because they are maxed out(on end points). Mostly on shifting servos, but it did cause the esc to overheat and shut down.

[Flippinrigs]

Originally Posted by Ditchrat

That sounds like a hung up brush or a comm that had a plate come loose. It would also explain your glitching and reset.


Situations like that draw high amps which might send the esc in to shut down.


You might try disconnecting the motor, then trying your original rear steer set up. See if the glitching goes away.


the other thing is check your end points, I have had cheap servos do all types of wonky things when they over heat because they are maxed out(on end points). Mostly on shifting servos, but it did cause the esc to overheat and shut down.

Should my esc still be okay? It sucks but I'm fine with replacing the motor, just dont want to have to replace the esc as well