How Do RC Car Brakes Work

[Evo_ermine]

Was just wondering, obvioiusly if i push the throttle trigger away from me the car brakes sharply. If I let off the throttle obviously the car will coast to a stop much slower than if I apply the brakes. But how does the braking system work, in an electric car, with no obvious brakes like on real car?

It might sound simple but I've never really thought about it before. It's obviously transmission based, rather than braking individual wheels like a real car.

Edited April 9, 2012 by Evo_ermine

[HATZY]

apart from leccy they use a disc and pad setup just like a 1:1 car

with leccy i dont know the exact physics but the motor is whats used to brake. i would have thaught by reversing the polarity so slowing down the motors movement, kinda like a retarder in lgv and coaches clamps onto the driveshaft

Edited April 9, 2012 by HATZY

[Evo_ermine]

I'm thinking about electric. I'll edit the OP. Ta.

[shaun17]

on a nitro, off the throttle servo you will have another linkage use your remote and brake, and you can see how it work

edit: ahh leccy, done thru the esc,

Edited April 9, 2012 by shaun17

[Revorocks]

Okay, on an electric car, you put energy in from the batteries, and it's converted into kinetic (movement) energy (spinning the motor which spins the wheels).

However, a motor is the same as a generator.

Put power into it and it will turn.

If you turn it it will generate power.

On an electric car it simply draws energy off the motor, slightly topping up your batteries (not much though).

This is how electronic brakes work.

However they only work when the car is moving, hence you can't have all electric hand brake on an electric car, otherwise it will just slowly roll away.

I could explain all of the physics part but I really can't be bothered

Edited April 9, 2012 by revorocks

[suicideneil]

^Regenerative braking- not all escs function like this as it is dependant on the type of motor / esc ( brushed or BL, along with hardware differences ).

Essentially though, the esc introduces a stall current to slow the motor down, or it will short the phases electronically to induce a stall- it won't reverse the polarity ( straight away ) as that would just destroy the drivetrain; if anyone has ever owned an old tamiya model with a mechanical speed controller, they'll know what I mean. How hard you press the brakes or how harsh you have them set will determine how quickly the motor grinds to a halt.

TL;DR? Voodoo magic man, frickin' voodoo magic....

[Evo_ermine]

^Regenerative braking- not all escs function like this as it is dependant on the type of motor / esc ( brushed or BL, along with hardware differences ).

Essentially though, the esc introduces a stall current to slow the motor down, or it will short the phases electronically to induce a stall- it won't reverse the polarity ( straight away ) as that would just destroy the drivetrain; if anyone has ever owned an old tamiya model with a mechanical speed controller, they'll know what I mean. How hard you press the brakes or how harsh you have them set will determine how quickly the motor grinds to a halt.

TL;DR? Voodoo magic man, frickin' voodoo magic....

Thankyou, that explains it a bit better. Cheers for the other replies too. Electricity really is a mysterious thing.

[Si Coe]

Of course what all this means is that for a 2wd like your Edge only the rear wheels have brakes - which isn't ideal as weight shifts forwards under braking and in a real car 70-80% of the braking effect comes from the front brakes. Some '4wds' also do this if they employ oneways - the are 4wd under acceleration but 2wd (rwd) under braking.

[Jack R8]

Of course what all this means is that for a 2wd like your Edge only the rear wheels have brakes - which isn't ideal as weight shifts forwards under braking and in a real car 70-80% of the braking effect comes from the front brakes. Some '4wds' also do this if they employ - the are 4wd under acceleration but 2wd (rwd) under braking.

Perfect for handbrake turns then

[Evo_ermine]

Perfect for handbrake turns then

Yep, it's very easy to spin it around by pushing the trigger too hard. Fun on tarmac. Maybe tricky to modulate properly in a race situation I imagine.

Edited April 14, 2012 by Evo_ermine