Another thing that can happen to cause unexpected WOT events is a broken ground on the throttle (or grounding problem inside the connector between throttle and controller).
trazor wrote: ↑
Jan 30, 2018 7:14 pm
I wonder how the "big brands" prevent this?
By having the controller fault and shutdown when such a problem is detected.
Yours already does this, but apparently not in a sufficient way.
As you note, however, it's possible for the "short" to be insufficient to be full supply voltage, but still be enough to be full throttle voltage. Not much the controller can do to differentiate that in a single-sensor throttle.
However, you could use a dual-sensor throttle, where one sensor and magnet is run clockwise, and the other goes counterclockwise, but both magnets fixed to the moving part of the throttle, so that both of them have separate signals that change at the same time. One starts at higher voltage and goes toward low, and the toher is "normal" and starts at low voltage and goes toward higher voltage.
It's not likely taht *both* of them would have the same fault at teh same time, so a controller that reads them will detect eitehr of them faulitng compared to the other, and shutdown.
YOu can build such a throttle by cutting two throttles up, and merging their mechanics into one with the magnet/sensor seciton of one of them flipped over vs the other. (or custom-machine one and use the bits from two inside it).
You could build a circuit that reads such a throttle, by inverting the voltage from the "second" sensor, then comparing the voltage between teh two. The comparator output (activated anytime there is a difference between the two throttles) would be the "error" signal output, used to drive the "disable" or "shutdown" control line of the controller. Then the voltage from the "normal" throttle is passed to the controller itself as the throttle signal. (or the inverted voltage from the other one).
If this unit is inside the controller case, then it's not possible for a wiring fault between the unit and the controller to cause a failure, as long as teh controller itself is waterproofed or itself inside a waterproof compartment.
However, it's still possible for stuff to get inside the controller, then it could still cause the same problem as at the throttle itself--it's just less likely to, since throttles are more exposed and vulnerable than controllers, typically.
Waterproofing the throttle might be another way, but it's VERY hard to *completely* waterproof stuff.
liveforphysics wrote: ↑
Jan 30, 2018 7:04 pm
The painted white lines in the road are more slippery than the asphalt when wet. I've often experienced the tire spin up going over them on bikes that had no throttle malfunction. Ebikes spin up the wheel really fast compared to ICE bikes of similar power levels.
I think that's half of what caused my ankle-breaking crash at the Death Race (though it was a crack-repair-strip on the asphalt rather than marker strip, and it was dry). Never know for sure, though.
12-C wrote: ↑
Jan 31, 2018 10:58 pm
To my knowledge the CA has a throttle short protection by detecting the short as a fault ( ie. 5V signal as mentioned above).
Can anyone comment of this being a cure for such a problem?
Sure--teh controller the OP has even did this (faulted and shutdown). But it's not perfect, and only works for over-limit voltages. Doesn't detect an undesired WOT taht is within the normal range.