Electric Buggy conversion w/ brake servo
 

I'm converting my Lois Eight to electric. I decided to run a clutch setup with a servo for mechanical brakes. I have a Mamba Monster w/2650 motor. My current radio has no mixxing ability, so I just picked up a y harness and connected up the brake servo into the throttle circuit as described in Tekno's info in the conversion chassis kit. The problem is this: the brake servo operates backwards - pushing on the brakes as the throttle goes up. I tried to reverse the connector and that causes the ESC to go into and error mode where it beeps and stops functioning. Same error if you try messing around with reversing throttle at the radio.
Before I cut the y harness and start swapping wires around there, I figured I'd ask here to see if anyone has an easy answer.;)

maybe you can try reversing the throttle on the radio and switch two wires from the brushless motor. you can also reverse motor direction using the castle link software

One option is to use a servo reverser. Not unusual with airplanes. Here are a couple examples:

http://www.futaba-rc.com/radioaccys/futm4150.html

http://www.rcdude.com/servlet/the-19...rser-V2/Detail

Or if you want to just rewire the servo, something like this:

http://www.youtube.com/watch?v=EK_FdRTenl0

Obviuosly flipping the connectors over doesn't actually reverse it (I would be done allready and not here) it seems to be the wrong combo of red / black / brown wires, so I'm wondering if I can get away with cutting the plug off the y-harness and rewire it there and get it right that way and be done with it fairly fast. Maybe keep the black to blask and swap red and brown???Also, correcting the direction there would allow for quick swap of the servo if (when) something happens to it.
I'm not sure the programming will help since it's split off the throttle signal.

You can't reverse your servo in the radio?

That will not work. And you risk letting the magic smoke out that all electrical devices operate on!

The red is a power wire, the brown (in your case, depends on brand) is the signal wire. Different functions, can't just mix them up.

Another option that may or may not work, can you mount the linkage to the other side of the servo? I'm guessing not, but just wanting to explore all possible options.

re-configure the brakes to work when pushed :). This is the most common way to fix this problem.

Nope - transmitter must be set with throttle on "normal" not reversed or the esc will not take it. It does nothing but the error beeping and no functions work.
Luckily, no smoke even though I played around with the wires!! Esc goes into a safe shutdown mode anytime the wiring isn't right.

And as far as I can see, there's no way to rework the brake linkage - it has cams to push the brakes which only work in one direction.
I think the real problem with this is the conversion kit flips the whole center diff / brake setup around 180* to make eveything fit / spur line up while keeping the brake servo on the same side.

I did , however, have one possible idea - so far Ive been messing around with Hitech and JR servos. I plugged in a Futaba and it operates the reverse of the others. I don't have any good Futabas (the one I tried is one that jammed on me the first time I used it - not one I would put in for racing).

Maybe it's time to go buy another radio with mixing capability.......

It would be cheaper to just buy a servo reverser.


Yeah, you can't reverse a servo by just messing with the 3 wire harness. Years ago, about 7 years ago, my first hobby grade rc was a emaxx and I rigged up rear steering, but the rear steering was backwards so it caused the truck to crab walk. Not knowing any better I thought, easy fix, just reverse the red and black wires and bam should turn the other way. Needless to say I ruined the servo in seconds.

When you reverse the throttle channel on your radio, are you redoing the throttle calibration on the esc? Anytime you change throttle profiles/settings like neutral/center point, direction you need to redo the throttle calibration.

If you are using a sensorless motor, just switch 2 of the motor leads, this will make the motor run the other way, recalibrate the radio to the ESC and you are good to go. You may need to reverse your throttle channel at the transmitter too. Otherwise the best option is the reversing Y-harness as mentioned above.

you are really lucky you didn't toast your esc or receiver. i'd also say a servo reverser is the way to go.... actually a 3 channel with brake mixing would be better, especially with all the money you've spent so far on a e buggy. You'd have much better adjustment of braking action, EPA, trim etc. on the fly from your radio. With a reverser you're limited to mechanical adjustments.