Steering servo bad?

[TRX4]

Ive owned my Defender for a year now and I'm experiencing my first issue with it. The truck will steer intermittently and will sometimes get stuck to the right or left. I'm assuming it's the servo since my batteries are fully charged in both the controller and truck


My question is, if I get the upgraded 330 or 400 servo from traxxas, do I need to run a bec for them to work or can I skip that for now? Thanks!

[amigaman]

You'll need a BEC for almost any servo in the TRX4, because the stock XL5 is very low on power.
The often recommended 1080 from Hobbywing is far better (6V 3A instead of 1A) and also has a better performance on the motor, and you won't need a BEC with at least standard servos.
The Traxxas BEC is only 6V and also pretty low on amps, so it won't really help, TRX parts are only good if you want an "all-TRX-Sticker" truck or need it to be absolutely plug and play because you and none of your freinds know how to solder.

So i would not recommend the TRX servos, there are a lot of alternatives out there that have equal or better performance but are far lower on price.
You just need to look they work with 6V and have the 25 tooth spline and the correct size.
A slight mod on the wiring will even free you from the 6V burden, you could have a so-called HV servo on a BEC while the rest of the truck still works with 6V, as the receiver and the small servos only work on 6V and can't be used on higher voltages.

[Fricker08]

The BEC will definitely help you get the most out of any servo upgrade you do. But for that kind of money you could buy a savox 1230sg 500oz or 1231sg 444oz. Just my $0.02
I had a 1231sg in a wraith that was great and I now have a trx4 with traxx that has a savox 1212sg 600oz. They can be a bit noisy but perform great.
I run a splitter that I modify to feed the servo direct from the bec so the rest of the truck stays 6v like amigaman pointed out.

[TRX4]

Originally Posted by amigaman

You'll need a BEC for almost any servo in the TRX4, because the stock XL5 is very low on power.
The often recommended 1080 from Hobbywing is far better (6V 3A instead of 1A) and also has a better performance on the motor, and you won't need a BEC with at least standard servos.
The Traxxas BEC is only 6V and also pretty low on amps, so it won't really help, TRX parts are only good if you want an "all-TRX-Sticker" truck or need it to be absolutely plug and play because you and none of your freinds know how to solder.

So i would not recommend the TRX servos, there are a lot of alternatives out there that have equal or better performance but are far lower on price.
You just need to look they work with 6V and have the 25 tooth spline and the correct size.
A slight mod on the wiring will even free you from the 6V burden, you could have a so-called HV servo on a BEC while the rest of the truck still works with 6V, as the receiver and the small servos only work on 6V and can't be used on higher voltages.

My goal is to stay away from a bec because I dont like the added complexity. Plug in and play is absolutely ideal but I dont care for name brand stuff either. I also would like it to be as quiet or quieter than stock so maybe I should just buy a OEM one and skip all the bs lol but at the same time I dont want it to fail again, i hear bad things about the stock servos in the trxrs. Wish there was something similar to the stock one with added reliability and same specs so I could utilize stock parts on it now

[QuesoDelDiablo]

Originally Posted by TRX4

My goal is to stay away from a bec because I dont like the added complexity. Plug in and play is absolutely ideal but I dont care for name brand stuff either. I also would like it to be as quiet or quieter than stock so maybe I should just buy a OEM one and skip all the bs lol but at the same time I dont want it to fail again, i hear bad things about the stock servos in the trxrs. Wish there was something similar to the stock one with added reliability and same specs so I could utilize stock parts on it now

The only way to absolutely avoid running a BEC is to invest in a Mamba X. Every other ESC doesn't deliver enough power with their on-board BECs.

Outside of that, your best bet is to invest a servo that's grossly over-powered (i.e.400-500ozin) and that way running with lower power input you'll still get 250-300ozin out of the servo.

And whatever you do, don't buy the Traxxas servos. Even a PowerHD from Amazon will be immensely better. (I'm actually a PowerHD user and they've been great for me).

If you're trying to avoid a BEC, avoid Savox servos too. They're notoriously power hungry.

If you don't want something "off-shore" (i.e. PowerHD, JX etc...), your best bet is probably a Hitec. Depending on your budget there's other options as well like Bluebird, Promodeler and more.

Be aware that Reef's are just over-priced/re-branded junk. 3bros might be ok but I haven't encountered too much from them so my ability to comment is limited.


*
My recommendation would be to get a servo bypass cable (Holmes makes one) and run a BEC with whatever servo you choose. It's really not a lot of extra complexity if you use that bypass harness and the benefits are huge.

[TRX4]

Originally Posted by QuesoDelDiablo

The only way to absolutely avoid running a BEC is to invest in a Mamba X. Every other ESC doesn't deliver enough power with their on-board BECs.

Outside of that, your best bet is to invest a servo that's grossly over-powered (i.e.400-500ozin) and that way running with lower power input you'll still get 250-300ozin out of the servo.

And whatever you do, don't buy the Traxxas servos. Even a PowerHD from Amazon will be immensely better. (I'm actually a PowerHD user and they've been great for me).

If you're trying to avoid a BEC, avoid Savox servos too. They're notoriously power hungry.

If you don't want something "off-shore" (i.e. PowerHD, JX etc...), your best bet is probably a Hitec. Depending on your budget there's other options as well like Bluebird, Promodeler and more.

Be aware that Reef's are just over-priced/re-branded junk. 3bros might be ok but I haven't encountered too much from them so my ability to comment is limited.


*
My recommendation would be to get a servo bypass cable (Holmes makes one) and run a BEC with whatever servo you choose. It's really not a lot of extra complexity if you use that bypass harness and the benefits are huge.

So your saying I can run a 4 or 500 oz without a bec I just wont be utilizing all the power from it? That's fine by me lol what model number do u reccomend?

[svt923]

Originally Posted by TRX4

So your saying I can run a 4 or 500 oz without a bec I just wont be utilizing all the power from it? That's fine by me lol what model number do u reccomend?

Without an adequate BEC you won't get all the servo torque or speed but there is also the very real possibility a high torque servo could draw all the available power and cause your receiver to shut down or fry the ESC's internal BEC in a worst case scenario.

[JatoTheRipper]

Isn't the Traxxas BEC plug and play? If so, any servo should plug into it. Make sure the replacement servo has the same number of splines do you don't need a new servo horn.

Not wanting a BEC is exactly why I replaced the XL5 with the Castle Mamba X or HobbyWing 1080 in my trucks.

[RCTom]

Another option is to use a servo that has an input power lead designed to run directly off of the battery (such as a Holmes Hobbies SHV500V; there are also others) and simply plug the JST power lead from the servo directly into the lead coming from the stock XL-5 ESC. In this configuration the servo bypasses the ESC's internal BEC altogether delivering full power to the servo.

If you're already using the ESC lead to power lights or some other accessory, you could make or buy a Y-harness that lets you power both the servo and the lights.

I run my TRX-4 indoor comp rig this way (sans lights) on 3S batterries with no brown-outs or other issues whatsoever using the stock XL-5 ESC and an older Holmes Hobbies SHV500 servo.

[amigaman]

Originally Posted by TRX4

My goal is to stay away from a bec because I dont like the added complexity.

Then you need to replace the ESC.

Originally Posted by TRX4

I also would like it to be as quiet or quieter than stock

The 1080 can drive the motor with 8 or 16kHz, so the motor howl is reduced.
Servo sounds can't be reduced, the 2075 is pretty slow and weak, and faster and or stronger servos are louder. Some are even more prominent, Savox is know to be beeping all day long...

Originally Posted by TRX4

Wish there was something similar to the stock one with added reliability and same specs so I could utilize stock parts on it now

Impossible because there is not sufficient power. Everything faster or stronger needs more power, anything working with the bad XL5 BEC is slow and weak.

Originally Posted by QuesoDelDiablo

The only way to absolutely avoid running a BEC is to invest in a Mamba X. Every other ESC doesn't deliver enough power with their on-board BECs.

This.

Originally Posted by QuesoDelDiablo

Outside of that, your best bet is to invest a servo that's grossly over-powered (i.e.400-500ozin) and that way running with lower power input you'll still get 250-300ozin out of the servo.

Nope.
That'll overload and destroy the BEC, nothing else.
Or you use a 8.4V servo and power it with 6. The it is far slower and weaker if it works at all.
Still, it most likely uses more than the half amp the XL5 can supply.

Originally Posted by QuesoDelDiablo

If you're trying to avoid a BEC, avoid Savox servos too. They're notoriously power hungry.

yup

Originally Posted by QuesoDelDiablo

My recommendation would be to get a servo bypass cable (Holmes makes one) and run a BEC with whatever servo you choose. It's really not a lot of extra complexity if you use that bypass harness and the benefits are huge.

A Y harness is enough:
- Top left is servo
- Top right is BEC
- Bottom is Rx
- Remove red wire from Rx end to isolate Servo BEC from the Receiver

Originally Posted by svt923

Without an adequate BEC you won't get all the servo torque or speed but there is also the very real possibility a high torque servo could draw all the available power and cause your receiver to shut down or fry the ESC's internal BEC in a worst case scenario.

That's true, and to avoid it the Y harness and extra BEC is ideal: The Rx and gear servos run from the ESCs BEC @6V, the servo can have a higher voltage, and whatever happens, the Rx won't brown out.

Originally Posted by JatoTheRipper

Isn't the Traxxas BEC plug and play?

It is, and it totally replaces the ESCs BEC that is only used as switch signal.
So it only works with the XL5 because it connects to the red battery plug.

Originally Posted by JatoTheRipper

Not wanting a BEC is exactly why I replaced the XL5 with the Castle Mamba X or HobbyWing 1080 in my trucks.

Which definitely is the better alternative:
- stronger BEC
- better Motor control
- silent

[Inspector86]

Originally Posted by JatoTheRipper

Isn't the Traxxas BEC plug and play? If so, any servo should plug into it. Make sure the replacement servo has the same number of splines do you don't need a new servo horn.

Not wanting a BEC is exactly why I replaced the XL5 with the Castle Mamba X or HobbyWing 1080 in my trucks.

The Traxxas BEC doesn't work like that. It only plugs in between the wimpy XL5 1a 6v ESC and the Receiver where it receives a pass through signal from the ESC and sends it on to the RX but boosts the power to 3a 6v.

I have been running an HW 1080 driving a Savox 1230SG with no BEC on my TRX4 Sport for a little over a year without any issues. I know it is not ideal but it does work. I have two other TRX4s with HW1080 and 1230SG plus a CC 10a BEC and HH bypass harness. The two with the BEC do have slightly stronger steering. My point is that the HW1080 and 1230SG will work without a BEC, they just work a little better with a BEC.

I do NOT recommend the Traxxas BEC or either of the Traxxas servos. They are over priced and under powered compared to what you can buy aftermarket. The Savox 1230SG is rated at 500 oz in at 6v for about $72. You can add a Castle 10a BEC for $24 and HH Bypass harness for $6. By using the HH Bypass harness this setup is 100% plug and play.

[amigaman]

Originally Posted by Inspector86

You can add a Castle 10a BEC for $24 and HH Bypass harness for $6. By using the HH Bypass harness this setup is 100% plug and play.

Don't forget the castle link to set up the BECs voltage. Also: "100% plug and play" would mean it is not necessary to solder the BECs input wires to the battery plugs of the ESC. Is that really so? ;) I can't find any product under the name "HH bypass harness" not even with "holmes hobbies", so i can't check myself.

[Fricker08]

Think this is the one
https://holmeshobbies.com/electronic...s-adapter.html

But I’ve bought a 3 pack of Y splitters for $11 and made my own

[TRX4]

Originally Posted by amigaman

Then you need to replace the ESC.


The 1080 can drive the motor with 8 or 16kHz, so the motor howl is reduced.
Servo sounds can't be reduced, the 2075 is pretty slow and weak, and faster and or stronger servos are louder. Some are even more prominent, Savox is know to be beeping all day long...


Impossible because there is not sufficient power. Everything faster or stronger needs more power, anything working with the bad XL5 BEC is slow and weak.


This.


Nope.
That'll overload and destroy the BEC, nothing else.
Or you use a 8.4V servo and power it with 6. The it is far slower and weaker if it works at all.
Still, it most likely uses more than the half amp the XL5 can supply.


yup


A Y harness is enough:
- Top left is servo
- Top right is BEC
- Bottom is Rx
- Remove red wire from Rx end to isolate Servo BEC from the Receiver


That's true, and to avoid it the Y harness and extra BEC is ideal: The Rx and gear servos run from the ESCs BEC @6V, the servo can have a higher voltage, and whatever happens, the Rx won't brown out.


It is, and it totally replaces the ESCs BEC that is only used as switch signal.
So it only works with the XL5 because it connects to the red battery plug.


Which definitely is the better alternative:
- stronger BEC
- better Motor control
- silent

Thanks for the info, very informative!