Outside power switch linkage

[JD and Beastlet]

Tired of taking the body off my TRX-4 to turn the power on and off, I rigged a mechanical linkage to allow me to do it from outside. I'm certainly not the first to do this, but I though I would share my approach.


I started with a Hitec cross servo horn - I have lots lying around.





I cut off one of the arms and shortened the remaining two. I had some 1/16" angle aluminum too, so I cut a bracket from that. It's stiff enough that the servo horn can be supported on only one side. That's done by a 2mm bolt and nylock nut through the bracket and the bottom hole on the downward servo arm; the tension on the servo horn is tight enough to keep it from moving on its own but loose enough to not keep pressure on the ESC power button. The black bands around the forward edge are 3 layers of heat shrink to better engage the power button, which does not protrude much. The brass part on the right is a 2-56 clevis, which passes through the floor.











The aluminum bracket is attached to the floor with 2 bolts and nylock nuts. a 2-56 bolt is screwed into the brass clevis, and that is the external link that turns the power on and off.


The setup works very well.

[brimdogg]

Nice, reminds me of the switch lever I had found and used when I had stock electronics still.

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[Inspector86]

It's just a good habit to unplug the battery when the truck is not in use.

[JatoTheRipper]

Originally Posted by Inspector86

It's just a good habit to unplug the battery when the truck is not in use.

It's more than a good habit IMO. It's required. If you do not unplug the battery from your truck you WILL eventually kill a battery.

[mebeknob]

Yeah when do you unplug the battery when you use this lever?


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[JD and Beastlet]

I hadn't though of that though I do remember reading about it in the Traxxas manual. Why is that necessary, and does it apply to NiMh batteries as well?

[drzoo2]

Originally Posted by JD and Beastlet

I hadn't though of that though I do remember reading about it in the Traxxas manual. Why is that necessary, and does it apply to NiMh batteries as well?

Leakage current.

Turning the ESC off only shuts down the BEC supply inside the device. There is still an electrical connection across the switch FETs inside the speed controller. FETs are not ideal and not truly "open" when not switching.

Over the course of weeks or months and depending on your battery charge, it will deplete your battery. If your just turning it off when your out crawling, there is no need to disconnect your battery. Assuming a few hours at a time, worst case.

Affects all batteries.

Sent from my HTC U11 using Tapatalk

[JD and Beastlet]

Originally Posted by drzoo2

Leakage current.

Turning the ESC off only shuts down the BEC supply inside the device. There is still an electrical connection across the switch FETs inside the speed controller. FETs are not ideal and not truly "open" when not switching.

Over the course of weeks or months and depending on your battery charge, it will deplete your battery. If your just turning it off when your out crawling, there is no need to disconnect your battery. Assuming a few hours at a time, worst case.

Affects all batteries.

Sent from my HTC U11 using Tapatalk

Thanks for the explanation. The switch will be still be useful during a crawling day but I will remember to disconnect the battery for longer idle periods.