What is that springy thing in a King Song 14D pedal wheel motor hub asembly?

[woke rider]

I was practicing jumps on my KS-14D and I landed with most of my weight on the back of the pedal. I was barely rolling forward at the time and when I landed on the EUC the pedal kind of sprung down and then back up again. It saved me from falling, but it wasn't a tilt back it was some kind of springy mechanism? What was it?

[mrelwood]

In which direction did it move? Backwards, or downward from the side of the pedal? Did both pedals move or just one?

Edited June 22, 2023 by mrelwood

[woke rider]

Both pedals just kind of sprung downwards in the braking direction. That happened to me when I was just learning how to ride too. It seems like some kind of safety mechanism built into the motor.

Edited June 22, 2023 by earthtwin
typo

[mrelwood]

It sounds like you overburdened/overleaned the wheel. The wheel didn’t have enough power to stay upright when you landed with your whole weight at the back of the pedals. The 14D is not a powerful wheel, and it can’t cope with sudden or hard accelerations and decelerations. 

[Mitch G]

You just overpowered the wheel.

[Cerbera]

I'll be honest - I wouldn't even try jumps on such a small, weak-motored non-suspension wheel ! Something's gonna give if you keep that up, probably the axle...

Edited June 22, 2023 by Cerbera

[woke rider]

I was concerned about the axle too. I don't want to break my wheel, but my 14D is more fun in a lot of ways than my Z10. If I broke it I would fix it for sure, but I don't want to break it in the first place. My 14D is my trick wheel.

[woke rider]

@Mitch G I'm not even sure what "Over powered" even means because if I charge my 14D over night and forget to unplug it as soon as the light turns green, then when I ride it the next morning, if I go down a hill my King Song will alert me, "Warning-Over Power" while I am breaking.

The bounce is mechanical, it's some kind of safety mechanism, it's not the same as a tilt-back.

[Cerbera]

6 minutes ago, earthtwin said:

I'm not even sure what "Over powered" even means because if I charge my 14D over night and forget to unplug it as soon as the light turns green, then when I ride it the next morning, if I go down a hill my King Song will alert me, "Warning-Over Power" while I am breaking.

In a riding / control input context, 'Over-powered' means over-leaned, and thereby too much demand placed on system, simple as that, which leads to pedal dipping and then cut-outs if you continue to push it.

That is completely different from the Overpower warning the wheel gives you downhill after a full charge, which is designed to alert you that regenerative braking such as you get downhill is nudging voltage up past the maximum achieved by the charge, which is not a good thing.

Edited June 22, 2023 by Cerbera

[woke rider]

Well, the warning is scary when it happens, but it's so slight that I rarely get the warning after the first 5 minutes after riding on a slightly over charged battery. Actually, I feel safer know that King Song actually has an audible warning for that "Overpowered"  condition. Whenever I over lean my King Song then I get a tilt back instead of a cut-out.

Edited June 22, 2023 by earthtwin
more info

[Cerbera]

2 minutes ago, earthtwin said:

Well, the warning is scary when it happens, but it's so slight that I rarely get the warning after the first 5 minutes after riding on a slightly over charged battery. Actually, I feel safer know that King Song actually has an audible warning for that "Overpowered"  condition.

The way to not get that message, btw, is to slightly stress the wheel before you get to the first downhill, so do a few pendulums back at base to bleed off the first volt or 2... and then go down the hill faster than you normally would so the regen is less. The reason it stops after a while is simply that when your power gets low enough, regen doesn't take it near the max any more.

Edited June 22, 2023 by Cerbera

[woke rider]

I have never gotten a perpendicular cut out with my KS-14D, but I have gotten like 100 tilt backs at high and low speeds depending on the charge state of my battery. The only cut out I ever had on my King Song wheel was when I tried to turn to suddenly at too much of a lateral angle. That also caused a short cut out that I recovered from with my Z10 at a really low rate of speed.

[Cerbera]

Just now, earthtwin said:

The only cut out I ever had on my King Song wheel was when I tried to turn to suddenly at too much of a lateral angle.

That's a good thing - you are obviously reacting to tilt-back fast enough to avoid the cutout.

[woke rider]

Tilt-backs are scary; I can't imagine somebody keeping on trying to go faster after a couple of tilt-backs.

[mrelwood]

 

1 hour ago, earthtwin said:

if I charge my 14D over night and forget to unplug it as soon as the light turns green, then when I ride it the next morning, if I go down a hill my King Song will alert me, "Warning-Over Power" while I am breaking.

I guess KS has saved valuable memory by only including one warning voice, but like @Cerbera so well explained, it’s an overvoltage warning due to regenerative braking. Actual overpowering is a different event altogether.

1 hour ago, earthtwin said:

The bounce is mechanical, it's some kind of safety mechanism

It is not. It is mechanical in the sense that you are overburdening the electromagnets in the motor. But only because there is not enough power in the said electromagnets that can keep the wheel upright by matter how hard it tries.

 All the wheel’s power is used for keeping the wheel upright. When you create a tilting force to the pedals that exceeds the wheels power to stay upright, it no longer stays upright. This applies to accelerating too hard, braking too hard, or slamming your body weight at the edge of the pedals (which is the same as accelerating too hard).

 And the available power to stay upright gets lower the faster you go, and the lower the battery level gets.

 Those are very important facts-of-lifes about all self-balancing vehicles, and comprehending them is important for staying safe on a wheel.

1 hour ago, earthtwin said:

it's not the same as a tilt-back.

Correct. A tilt-back is a preprogrammed intended behavior. Overlean happens when the wheel’s intentions are not enough.