Yeah, I actually thought I'd been in Mission, but the phone app said Cruz. I wonder if the loss of power also toggled the shaping somehow.
Posts made by ggould
Riding along, just getting onto the ramp into a parking lot, my OW+ stopped going. I of course kept going, though it was a minor fall and nothing but a bit of road rash.
When I returned to the OW+ after brushing myself off I was surprised to find that it was powered off. Powered off as in, phone app not connected, no lights, no blue LED. I had to power it back on to keep going. This seems odd -- certainly different from my previous falls. It even seems suspiciously like a board issue rather than user error (although I still assume it was some sort of user error -- I'm under 100 miles and still working out the kinks).
To cover the obvious bases: Battery at 82%, Cruz profile, traveling at low speed (perhaps 6 mph), going from flat road to slight upward incline.
I'll admit it makes me a bit nervous -- if there's a sudden power-off condition and it happened at speed or near traffic I could be in quite a pickle! Is there a known behaviour that I might have tripped through inexpert riding or should I worry that there's a loose power coupling?
RE: What's your cruising speed? 14mph? 20mph?
I mostly cruise about 13mph; this is because I am old and fragile and don't want to die just yet. In praise of this speed, however, let me point to my constant companion in my automotive research job, the fatality/speed graph:
Note the sharp increase from 20 kph (~12 mph) to 30 kph (~18 mph).
Now this doesn't mean we're risking death -- those numbers are for car collisions, which are more like going full speed into a wall than like falling off a plank, and those folks weren't wearing helmets. But it gives you a good idea of how much the hazard level starts to ramp up as you push toward 20mph. Roughly, energy goes as the square of speed, injury goes as the square of crash energy, and in a crash all that energy has to go somewhere.
RE: One-wheel Plus noise while stopped
Most gyros-on-a-chip are MEMS coriolis gyros (vibrating rings whose vibration modes rotate while the ring itself does not) or fiber optic gyros (where a light pulse in a a fiber optic loop is the "moving part"). Low-end MEMS gyros run about $2 in large quantity and can be only a few millimeters, so that's the way I'd bet.
So actually a gyro, but a really tiny one with very little inertia. And really tiny gyros can "spin" physical abstractions like vibrational modes and photons rather than hunks of metal. It's the same physics and math as a classic gimbal-and-ring gyroscope, but tiny and cheap and won't take your finger off if it slips.
RE: Help understanding "overcharge"
@gadgetrider The last brake chopper I worked with (on an agricultural robot) weighed five hundred pounds and needed a separate radiator to keep from melting, so my knowledge of such things has little application to the OW.
In general the OW design seems to be working near the limits of practical heat dissipation, so I am confident that FM's engineers have considered this.
RE: Help understanding "overcharge"
@djinn With most motor systems, that is precisely regenerative braking -- the amount of battery power to apply negative torque is negative, so you get regeneration for free with braking. The only limit is your ability to sink that power, which is why heavy vehicles with regen brakes also have a "brake chopper" (a huge resistor bank) to sink more power than the battery can take (and then a huge heat sink to dump the resulting heat).
RE: Boston-area advice
Okay, here is one data point: T cops watched apathetically as I locked up my OW+ in a bike cage. So that's apparently legit-ish, even if technically prohibited.
(To live in Boston is to live in the gray zone between what is illegal (nearly everything) and what anyone actually cares about (nearly nothing))
RE: Fender with battery inside
I'd worry a bit about safety.
The current battery is bracketed by basically all of the OW's structural elements -- it's in just about the safest place in the whole OW (second to the wheel hub). You are going to need to armor a battery in a more exposed position -- if the wheel ingests a rock and pins it to the battery from below, the maximum torque of the hub motor times its maximum ground speed is the amount of power your battery armor needs to be able to absorb in a collision. This is not a small number.
At minimum I think you'd want cushioning or breakaways in the fender mountpoints?
RE: Question for urban riders
Tried the hop approach on my morning commute -- the sidewalks are wicked uneven but if I can use them they're safer than the road. It worked pretty well, but it takes some practice to scale the size of hop to the size of bump. Of course I was approaching the discontinuities at a 90 degree angle because swerving all over the sidewalk isn't neighborly.
I found that losing contact with the board was a much bigger concern than the board not mounting the step. The hop gets noticeably easier and smoother at speed -- approach fast, brake hard, and hop seems to be a good recipe.
I'm definitely strapping on pads before I practice higher speeds and bigger bumps, but this feels promising.
Got my OW+ a week ago on a whim; I've had a few falls and I'm a bit beat up but I think I'm learning.
I'm interested if any riders in the Boston area have specific local advice. The general unevenness of the sidewalks has been a problem for me, for instance -- I've taken one hard fall from misjudging how big a pavement edge it can power over.
I'm also interested if folks have experience interacting with the MBTA. I know one isn't allowed to carry electric devices like this on the subway, but is that enforced in practice? How about on buses? Are they allowed to be locked in the bike cages at the stations?