HW 1080 esc and 7.4v servo
 

I know the HW 1080 has a 7.4v setting for the internal BEC. I’m going to use a servo that can handle 7.4v. Will the internal BEC provide the power needed to get the most out of the servo, or would I be better off using an external BEC like the HeyOk nobrainer?

Re: HW 1080 esc and 7.4v servo
 

What model servo? The Hobbywing will power most servos from its internal BEC...

Re: HW 1080 esc and 7.4v servo
 

When I installed my wp1080 I was still advised to run an external bec. Yes it was from my lhs owner, but no, it wasn’t just to sell me more parts. I don’t know the technical reasons, but I trust his advice.

Re: HW 1080 esc and 7.4v servo
 

Internal BEC is fine on the hobbywing IMO. I slapped a 500oz torque servo on mine and it yanked my C hubs right off the damn axle! Id say it has enough amps for most users easily.

Re: HW 1080 esc and 7.4v servo
 

It’s the new traxxas 400. Long story about why that particular servo

Re: HW 1080 esc and 7.4v servo
 

The motor in my traxxas trx4 sport died along with the esc, so I’m putting in a HH trailmaster 550 21t with a HW 1080. I’m actually excited. 49 yrs old and like a kid waiting on Christmas morning.

Re: HW 1080 esc and 7.4v servo
 

The Traxxas servo should be fine working off the internal BEC. There are people running the ProModeler 470oz-in servo from it without issues...

Re: HW 1080 esc and 7.4v servo
 

10-4

Re: HW 1080 esc and 7.4v servo
 

The concern is Amps and if it can supply enough for your chosen servo.

The HW1080 has a 3A bec on board so it push *most* servos just fine but some that are higher draw (Savox comes to mind) will want more amps and may brown-out during high load applications.

Re: HW 1080 esc and 7.4v servo
 

Correct me if I'm wrong, but most receivers (especially in RTR's) can't handle 7.4v
That's why people recommend an external BEC

Re: HW 1080 esc and 7.4v servo
 

^^This.

Check your specs for receiver and servo draw.

Super cheap radio may have a volt limit it will run on - no problem with a spektrum - AFAIK their volt range is 3.5-9, so 7.4 is no problem, even 8.4.

Servos up to about 300oz/in will draw up to about 3.5ah at full load/stall. Greater than that will generally draw more. This is where you could stall out or brown-out your circuit causing glitching, burning, any number of issues. You're pulling too many amps through your ESC and reciever. And that's why anything from 400oz/in and up all recommend an external BEC. The Castle one is easy to setup and provides 10ah to power your servo. And I think you can set the volts with it as well.

There was a nice test and report done around here somewhere that rated a bunch of servos of varying torque and volts, and what they draw at stall. Pretty much anything over about 300oz/in was well over 3ah draw.


You might get away with it for a time, or you might burn things out too.

I run 6.0v servos at 7.4 as well. They sing pretty well there, and have not burned one out. Wore them out - the shaft gets sloppy which makes your front wheels wiggly, but no issues running them.

I have also run LED light controllers rated at 4-6v and definitely burned it out on 7.4volts. "What's that burning smell???" LOL

Some stuff you can get away with, some not. Or for a time, and then POOF!! :mrgreen:

Re: HW 1080 esc and 7.4v servo
 

Most modern receivers should be OK up to 2S, but it's always smart to verify that with your particular model BEFORE you find out the hard way that it's not. I've learned that it's very difficult to put the smoke back into electronics.

If your receiver can't handle higher voltages, rather than cough up $20 or more for an external BEC, as nice as they may be, for under $1 you can pick up an adjustable buck converter, or get a non-adjustable 5V buck converter. These do exactly the same thing as a BEC except that they have lower current handling capacities and they're a lot cheaper. Instead of using it to send higher voltage to your servo, you can set your ESC's BEC to your desired voltage, then use the buck converter to lower the voltage going to your receiver and other lower voltage accessories.

Re: HW 1080 esc and 7.4v servo
 

garage-boo, just be aware that the stock TRX4 electronics are rated at 6v so if you use the 1080 without a BEC the voltage you set the 1080 at will also be the voltage the receiver sees. To be safe, you need to set the 1080 to 6v to power the receiver and servo. If you want to power the servo at 7.4v you will need to install an external BEC like the CC 10a and the HH Bypass adapter harness. One reason I like the Savox 1230SG is because it is rated at 500oz/in at 6v making it compatible with the stock electronics and the HW1080 has no problem powering the setup.

Re: HW 1080 esc and 7.4v servo
 

Thanks for the info and will do

Re: HW 1080 esc and 7.4v servo
 

I ordered a different rx that will handle up to 8.4

Re: HW 1080 esc and 7.4v servo
 

That will work too! Keep in mind that by eliminating the TQI transmitter you will no longer be able to take advantage of the Traxxas telemetry options.

Re: HW 1080 esc and 7.4v servo
 

This is all good stuff to know. I've wondered about what's the upper limit of my HW 1080 in terms of how powerful of a servo it can support before a BEC becomes necessary. I'm currently running an EcoPower WP120 (337 oz-in@6.0V and 400 oz-in@7.4V) and it seems fine, but it's still early days. Nice to know that others have gone just a little more powerful than that and not had too many problems.

Re: HW 1080 esc and 7.4v servo
 

Maybe it will help you rest easy to know... I'd been powering a Savox 2290sg from the HW 1080's bec at 7.4v for the last ~6 months and had zero issues. Yes, the 2290 is rated at 9.2a at stall, yet it never glitched or browned out, had no shortage of turning force, and nothing ever got too hot to touch. The 1080 is a tough little bugger!

I did recently switch all of my electronics in that car (except the 2290) so it is now powered by a CC 10a bec at the same 7.4v, and it does turn with even more authority. That right there tells you that it was not previously being supplied with all the juice (amperage) it asked for.

In short, the 1080 will do fine on its own, but if you've got a hungry servo, it will be even better powered from an external/higher amperage bec.

Re: HW 1080 esc and 7.4v servo
 

If you end up deciding to stick with the Traxxas tx/rx stuff, the info I provided above about using a buck converter will allow you to retain the Traxxas receiver while still allowing the ESC to provide 7.4v to the servo.

Re: HW 1080 esc and 7.4v servo
 

I'm curious of how wiring this would be achieved? Being that the receiver is basically the "hub" of all your connections.