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Everything posted by Mono

  1. It seems quite unlikely that this would make any notable difference. Given the same air pressure however, a wider tire has less rolling resistance and hence should give the larger range. Having said that though, even the tire construction and the used materials probably have a much larger influence than the size in itself.
  2. Racing bikes have narrow tires to 1) minimise air resistance and 2) minimise weight. If one wants to minimise rolling resistance, a wide tire is better. The reason is that, given the same air pressure, a wider tire undergoes less deformation. For day-to-day use I personally find the comfort a thick tire provides more important than any other parameter, even on a bicycle.
  3. The issue is trying to counter gravity by blowing air downwards. Lifting 100kg with 10km/h takes in itself 2.7kW, or in other words, lifting 100kg by 10m takes 2.7Wh.
  4. The main safety concern though is not the riders who indeed should know their risk, but everybody else who may not know the risk and should not need to care. Protecting our fellow citizens should be our main safety concern, always, not protecting ourselves. Of course, if you only meet one of them twice a day, this concern doesn't need to be that big.
  5. On a decent wheel like the InMotion I would be pretty confident that a cut out only happens when one exceeds the maximal speed (which should be beyond 30km/h for the V5F). Before that, the wheel might still not be able to deliver enough power to keep the pedals horizontal. Fortunately, this is quite different and a situation from which I have recovered in the past without going down. Tiltback advances the wheel in front of the rider and makes it very difficult to accelerate further. That's what it is for. I have the same impression as you though: hard braking seems to become more difficult under tiltback and one may well have the fear to slide down the pedals. I think, as usual, bent, soft knees help to mitigate the problem even though they make the foot positioning even more awkward in this case. I also agree that tilt forward can be a perfectly feasible way to notify the rider to slow down and it has happened to me once or twice on different wheels when I apparently reached the power limits of the motor. A wheel that gets suddenly soft and mushy gives a great incentive to slow down. I don't think though that it would have the advantage to make braking easier. In particular to initiate braking becomes rather more difficult.
  6. I think to set the tilt back speed to a lower than the maximal value is a good idea and the best you can do. I am doing the same on my V8. This has two beneficial effects. The wheel is always further away from its power limits and from its cutout speed, and when a crash happens, it happens at a lower speed. I do not expect the wheel to ever cut off due to running into the tilt back speed but only due to running into/over the cutout speed.
  7. Yes, it's perfectly OK. The only downside: due to the weird and changing foot positioning, the wheel may be more difficult to control.
  8. I was just citing what you said: Aaaaand of course, with higher voltage comes higher power motors... If you define an increase of 25% to be going through the roof, right Just for a rough reference: EUC: 1kW at 60V -> ~17A Tesla: 2x200kW at 400V -> ~2x5000A
  9. It took much longer for me. Less than an hour but certainly way more than 10 minutes. I would calculate 20-25min for changing the battery. That is the reason why I abandoned the idea to carry a second battery for increasing the range.
  10. I have never heard of a firmware update for InNotion wheels.
  11. All true (well, almost, higher voltage does of course not always come with higher motor power. Voltage and power are independent specifications. We can well have a 50V 1000W motor and a 100V 400W motor). Nobody in the right mind would deny that there is a difference between 67V and 84V. Yet, this seems neither to explain why this 25% difference may be decisive, nor that any of these consequences cannot be achieved through other means, e.g. 25% thicker wires or...
  12. Depends on which market one wants to take over
  13. Mit oder ohne Helm?
  14. For showing off: 00~ 00~ 00~ 00~ 00~ \ | | _| _/ /\ /| /| / / \ \ / / / \ \ \ | / O O O O O For playing it safe: 00~ 00~ 00~ 00~ | | _| 00~ | /| /| | _| /| / / // __| /_ \\ \ \ \ O O O O O
  15. Analysing the data, I found a negative correlation between tilt back angle and current in the above graphs. It remains negative when taken from second 31 or when removing acceleration in a multivariate linear regression. AFAICS it's not likely a direct causal link, as I still have no reasons to believe that tilt angle effects energy demand.
  16. Tilt-back is a mechanism to incentivise the rider to slow down. The mechanism is simple: the neutral inclination angle of the shell and hence the pedals is changed from horizontal to negative, tilting the pedals back This gives the rider the incentive to initiate a slow down (see also below). Here I discuss my understanding of the energetic (and a few other) consequences of tilt-back. Remember the feeling to lose the ground under your feet when the tilt-back sets in? Here is why. Simple geometric consideration reveals that if the riders feet stay in contact with the pedals, tilt-back raises the riders front feet and lowers the riders heels. Lowering ones heels feels like losing support and means that the riders body lowers as well if the heels remain grounded. The effect from the centre of mass: most of the work to raise the riders body (or the toes ) is done by muscles, hence the energy comes from the food the rider has digested. (Lifting 102kg by 1cm loss-free needs about 10W=102*9.81*0.01W for one second or 100W for 0.1s thereby adding 2.78mWh=10/60^2Wh=0.0024kcal to the potential energy of the rider). However not only the rider needs to work: when the wheel pushes the rider forward (or backward), straightening up or raising the riders body adds momentarily to the riders perceived weight and hence to the power demand of the wheel. Vice versa, bending the knees or lowering the body gives the wheel a short period of decreased power demand (perceived decreased rider weight). Lowering by 5cm would remove the entire rider weight for 1/10 of a second. This is definitely something one should exploit in any critical situation: the reflex of bending the knees to keep or restore the wheel under the rider is a life saver! I had two or three quite surprising saves from intentionally going rapidly-almost-falling-like deep into the knees. Unfortunately, going deep into the knees is particularly difficult and somewhat physically limited under tilt-back. Yet, soft knees are our suspension. Soft knees get us over bumps and out of potholes. Bending knees is THE invaluable reflex when riding an EUC. But I digress... First summary: when tilt-back sets in, the riders heels lower and (without body posture change) the riders centre of mass lowers and this leads to a small but possibly notable power demand reduction. The effect from the change of tilt angle (here I stand corrected): because changing the tilt angle backwards increases the speed of the motor traveling relative to the shell, changing the angle requires energy. The amount however seems to be rather miniscule. If we travel 20km/h=5.6m/s with an 18" EUC and change the tilt angle from 0º to -10º in 1 second (pretty scary, IMHO), the shell position changes over the wheel circumference by 4cm = 10/360 * 18" * π. Hence, the circumferential rotation speed increases for 1 second by 0.72% = 0.04m/5.6m, i.e. by less than one percent. I am actually not sure what the power demand of this mechanism is (between 0 and 1.4% seems a good guess), but to all I can tell it must be negligible. Tilting the wheel also lowers its centre of mass. Lowering 20kg by 1cm in 1s may deliver 2W for 1s at most. Second summary: all in all, I do not dare to decide whether the effect from titling the wheel saves or demands a very small amount of energy. For the remainder, the simple but conclusive approach is to considered energy conservation: any consumed energy from the battery must be converted into kinetic energy or potential energy or heat. After the tilt angle has changed, from the energy balance perspective nothing is different to the situation before. If the wheel consumes additional energy, it produces more torque. More torque leads to acceleration (hence energy is converted to and conserved as kinetic energy), just as it happens without tilt-back or while the tilt-back sets in. Some people feel that under tilt-back they seem to apply more pressure to the front foot, or equivalently, that the wheel applies more up-pressure. This means that the wheel produces more torque to provide this counter pressure. Torque however invariably leads to acceleration of the wheel (or the wheel and the rider). The other way around, if the wheel does not accelerate, this feeling is a perception due to the uncomfortable foot position but not actually an increased up-pressure. Finally, slowing down the wheel, with or without tilt-back, can be accomplished by initially accelerating the wheel to the front of the rider. Tilt-back is the invitation to do exactly this. In particular, if the rider does not adapt to the changing neutral tilt angle, the wheel accelerates (without the rider and quickly). This acceleration requires some additional power (less than the acceleration of wheel and rider). With the knee-bending trick applied immediately, the additional power to initiate braking can at higher speeds probably be reduced to zero.
  17. That's right, the current is not limited in a controlled way. Then the weakest element in the chain is likely the battery with the smaller voltage experiencing an overvoltage and overcurrent under charging.
  18. Is it multifunctional in that the wheel can rest on it staying upright? Should be doable.
  19. I have been letting ride quite a few strangers, mostly kids, but not only. I can't even remember a single case of someone who was brave enough to get on and obviously put off afterwards. There was one girl who I didn't even manage to get standing on the wheel (my fault, I guess, I have a steep and slow learning curve as an advisor), who I assume wouldn't consider to pursue even if she had considered before. It helps though that the "brave" are usually above average in climbing the initial learning curve.
  20. No, below 85%.
  21. I was trolleying my V8 and started running (was in a hurry). Surprisingly the V8 started to beep, I believe like when speeding. Surprising? No, not because I couldn't run so fast but because the wheel was off at the time. The observation is reproducible: only when off the wheel starts to beep when pushed quickly via the trolley. Has somebody else observed this and what's it for?
  22. Maybe you don't talk about the same situation? To parallel cells with different voltage is rather detrimental, as it will overcharge the cell with the smaller voltage (it will be charged until no voltage difference is left), no?
  23. I do have scraping when I have been riding on dirt ground. When the tire is clean, there is none.
  24. Yeah, it takes a little more practice to trolley comfortably without turning it on. While off needs more work than on, I can easier pass over curbs and stairs only by lifting by the trolley handle.
  25. Where do you have this information from? AFAIK, if you wire two identical packs in parallel, they behave like one pack with the same voltage and twice the Ah. From the electrical perspective (physical location aside) they are like one pack with twice the Ah. Also for a third pack added in parallel they look and behave exactly like one pack with twice the Ah. For a forth pack added in parallel these three packs look exactly like one pack with three times the Ah...