Using a BEC with a 5-wire servo?

[Jim85IROC]

:lmao:

I know this question sounds ridiculous, but I'm asking anyway. My Clone Hammers uses crap electronics including a 5 wire servo. This servo is extremely weak and has a hard time turning the 1.9s. It's getting replaced along with the rest of the electronics soon, but before I do that, I want to try an experiment. I'm going to measure the voltage going to the servo, and depending on what it is, I may try raising it a bit. I'm expecting to see something below 6V being supplied, and if so, I'm going to raise it to 6.0V to see if the servo performs any better. Once I get closer to swapping the electronics, I'll try raising that voltage to see how much the servo can tolerate.

Out of curiosity, has anybody tried boosting the voltage on a 5 wire servo before?

Who wants to place bets on whether this works or I just end up smoking the servo? :mrgreen:

 

[Hydrocarbon92]

Usually electronics are rated in voltage steps such as 3/4/6/8/10v etc. They're also usually rated 20% greater than their target, and and usually 1 step higher for caps/transistors/etc.

I did a quick search at 5-wire servos appear to be just a motor & pot inside, so the ESC/RX combo deals with signal & power internally. If you're lucky, it will use transistors to send power, and you might be able to up the power on their collectors. IMO it might be easier to get a cheap flysky 2ch system & mod micro servos to fit.

 

[Jim85IROC]

There's no need for micro servos. The steering on this car is a full size servo, and I'm going to be replacing all of the electronics soon enough, but before I do I want to see if I can get the 5 wire to perform better. As you mentioned, things usually go up in somewhat incremental values, but I forgot that the 5 wire is just a motor & pot. The buck converter idea won't work so I'll use a MOSFET switch instead. That's easier than trying to crack open the ESC and power the collector of the existing driver.

 

[Hydrocarbon92]

It would probably need to be some sort of an H-bridge and/or diodes. Servos usually work by swapping the motor poles and braking by pulling both poles to ground. The actual control circuitry is usually an h-bridge with 2ch N- & P-channel mosfets or dual 2ch N-channel where one channel is high-side and the other is low-side.

If you know more than I do, let me know what you figure out. It could be used to turn a normal servo into a high-voltage servo.

 

[Jim85IROC]

No, I think you're right. I was trying to imagine this while I was working, so I was only half paying attention to it. I figured the MOSFET could switch a higher voltage, but neglected to remember that it needs to be able to reverse the polarity to go the other way. I may try to use 2 MOSFETs with a couple diodes, but by that point it would probably be easier to work up an H bridge.