Stock receiver specs

[mmn]

Can't find specs for the TRX4 Sport receiver. I'm going to a Hobbywing 1080 ESC which has the capability of running the internal BEC at 7.4 volts for high power servos. The stock ESC runs the BEC at 6 volts. My question is if/when I go to a high powered steering servo, can the stock receiver handle 7.4 volts?

Regards
Michael

[GA Dawg]

Mine didn't.

[Dirt Runner]

I have an external bec on mine for a few years and still on the stock rx no issues. The esc regulates the voltage. I don't see why you should have an issue.

Sent from my SM-N950U using Tapatalk

[mmn]

Originally Posted by GA Dawg

Mine didn't.

What was your solution?

Regards
Michael

[amigaman]

All TRX electronics have 6V max, even the power servos that need the TRX BEC, that has 6V 3A.
That includes the Rx and shift servos, too.
To have your steering powered by a higher voltage you'll need a second BEC for it and leave the rest on 6V, or replace everything with stuff that can withstand 7.4V.

It's easy to supply the steering only with another BEC by modifying a Y cable.
Plug Servo and BEC into the top arms of the Y, remove the red wire from the bottom end (Rx end) of the Y and plug it into the Rx.
Ding, ESC-BEC powers everything except steering on 6V, steering can be powered by whatever you like.
This way a blocked steering will also not brown out the rx.

The only problem is you need to supply the second BEC with battery, that usually needs soldering.
You could look for wire connectors like these: https://www.wago.com/de/installation...emme/p/221-413
They're available as fakes from china too, makes connecting something to the battery easy:
- cut the original ESC battery wires
- strip the isolation
- plug them into one of those connectors each
- add ESC wires
- add BEC wires
done.
You need two connector blocks! DO NOT PLUG PLUS & MINUS INTO ONE BLOCK! THATS A SHORT AND WILL CAUSE A FIRE!
These blocks are available as 2, 3 and 5 pins, so you could easily connect battery, BEC and ESC with a 3-port block, or use the 5-port and add e.g. a winch ESC and lights.
China fakes may be available as 2-poles-in-one-block, watch out for the connections.

[mmn]

Thanks all. After Jens' answer above and following a bunch of threads, the answer is "no", even though some have done it with mixed results. Traxxas doesn't say it in their specs, but there is a line in their Binding instructions that says the receiver must be connected to a 4.8-6v power source.

Common solutions are to either run a second BEC and a Y adapter that delivers 7.4v to the servo and signal from the receiver, or move to a receiver that can handle 7.4v.

Interesting that Traxxas sells a 400 gram servo that is capable of 7.4v but a) they don't tell you the torque at that voltage, and b) the BEC they recommend to power it only does 6v. It just takes the servo load off the stock ESC.

Regards
Michael

[Greatscott]

Originally Posted by Dirt Runner

I have an external bec on mine for a few years and still on the stock rx no issues. The esc regulates the voltage. I don't see why you should have an issue.

Sent from my SM-N950U using Tapatalk

Not sure what is really going on here...

The external BEC has to be set to a specific voltage. When running an external BEC, no voltage should be coming from the ESC, if there is, you didn't remove the red wire out of the connector like you should have.

You likely don't have an issue because your BEC is likely set for < 6VDC.

Originally Posted by mmn

Thanks all. After Jens' answer above and following a bunch of threads, the answer is "no", even though some have done it with mixed results. Traxxas doesn't say it in their specs, but there is a line in their Binding instructions that says the receiver must be connected to a 4.8-6v power source.

Common solutions are to either run a second BEC and a Y adapter that delivers 7.4v to the servo and signal from the receiver, or move to a receiver that can handle 7.4v.

Interesting that Traxxas sells a 400 gram servo that is capable of 7.4v but a) they don't tell you the torque at that voltage, and b) the BEC they recommend to power it only does 6v. It just takes the servo load off the stock ESC.

Regards
Michael

Very good synopsis.

Sadly, no matter how you slice it, there will be a tradeoff. In your solution above the electronics on your rig are a bit complicated, and can make the wiring messy. The "clean" solution is to run another TX/RX that can handle the higher BEC voltage, but then you lose functionality of the stock TX, like cruise control, and you still have to manage the power to your mini servos, unless you ditch them altogether, or upgrade them to a mini that can handle the voltage.

[Inspector86]

Another option is to run a hi torque servo that is rated at 6v. For example, the Savox 1230SG is rated at 500oz in at 6v. I have a couple of TRX4s running stock RX 1230SG and all powered with only a HW1080 at 6v. If you choose to run an external BEC to power a servo at 7.4v the HH bypass harness works great.

https://holmeshobbies.com/electronic...s-adapter.html