Christoph Zens

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About Christoph Zens

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  • Birthday 02/18/1973

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    Vienna, Austria
  1. Same here. For me, left turns were much easier in the beginning. I also wondered why that is and what I do different during a right vs. a left turn. Eventually, I found out that I didn't really look into the direction I wanted to go when doing a right turn. This lack of really facing the way I wanted the wheel to go caused the problems for me. In my mind, I figured a right turn, but my body was not acting like it so the wheel was not doing what I wanted either. The feeling that the wheel would not want to follow me made me act even less confident when entering the turn, so this was like a circle of action and reaction I had to break through. Once I started to concentrate on facing the direction I wanted to go first and let the body and wheel follow automatically, things became much easier. I also used the same technique later when I practiced 180 degree spot turns. I started to practice them relatively early since I consider this maneuver essential for safe riding. It comes in handy when one needs to turn around in a confined space. Again, I had problems to do the full 180 degrees at the beginning when trying to do a right turn and again it helped to first turn around and face the desired target direction before actually executing the move with the lower body. Another good way to gain more confidence and even out the left/right preference is to go slow on a straight path and sway left and right evenly, just like one would do when skiing.
  2. That's also what I heard (although from a reseller, so we have to take that with a grain of salt). He said that they don't care about individual sales and there is no after sales support to be expected directly from the factory, but more interestingly, he said that any beta units or first batches of a new product, which a knowledgeable reseller won't buy for one reason or another, are going into direct sales. For example, the first batch of KS16S apparently had different (not quite optimal) battery cells, which were then changed to something else for future batches. So my reseller held off and did NOT buy from the first batch, because he wanted the units with the new cells for his customers. Again, I'm only repeating what he told me, and I can't really verify it at this point, but it does make sense to me and I don't see why he would come up with such an elaborate story if there is no truth behind it.
  3. Well, sometimes the answer is WD40. As we all know, all of life’s problems can be solved with two things — duct tape and WD40. If it moves and it shouldn’t, you need duct tape. If it doesn’t move and it should, you need WD40.
  4. It's great that they let you configure this however you like on modern wheels. For the NB1, I was paying closer attention recently and now I'm not even sure if what I wrote about firmware 1.4.0 is entirely correct. Their algorithm seems to be somewhat more complicated. For example, when I ride on a very smooth and flat surface and accelerate slowly up to top speed, I get tilt back without any beeps. However, when there are bumps, or I'm climbing a hill, I get the beeps before any tilt back. Maybe these are the power draw beeps. This is maybe the same on modern wheels. Not configurable and independent of speed. So, what does a KS16 with tilt back speed set lower than alarm speed do when it reaches power limits? Does it then first tilt back or beep?
  5. Interesting, they seem to have upgraded the battery. My almost 2 year old NB1 E+ came with the pink LG MG1, rated for 10A continuous, 2.8Ah capacity. One could argue that even with those cells, something like 1.2kW average power would be OK, when the motor is only rated for 500W. Maybe they upgraded for safer downhill driving, because that's where the older cells are out of spec. I see readings of 12A reverse current when going down a steep hill. That's a 2C charge for the MG1 cells, which is not good.
  6. I replaced my Ninebot One E+ battery when it was around 1 year old and worked for 1000km. The thing I noticed was that it did not perform well in cold weather (sub zero degree celsius) and that the shrink wrap started to have holes in it due to the battery moving in the housing on bumpy roads. Also, I found out that the original battery had no balancer, which would cause truble in the long run when charging (over charging some of the cells). This was a major safety concern for me, so I decided to swap the battery out ASAP. I got a much better battery from a German shop (1RadWerkstatt). He uses better cells and a better BMS, including the necessary balancer circuit to make sure none of the cells are over charged. For the Ninebot One E+, his battery has 388Wh and the cells he is using perform much better in cold weather. Here is a link for reference: http://www.1radwerkstatt.de/epages/80603321.sf/en_US/?ViewObjectPath=%2FShops%2F80603321%2FProducts%2F"15S Ninebot" However, almost another year and another 1000km later I am in the market for a new wheel and pre-ordered a KS16S. At the time I decided to swap the battery, this model was not available yet and all the 16" wheels had 800W motors, which did not sound like that big of an upgrade to me, but now that there is a 1200W and >800Wh 16" wheel, it is very tempting to just get an upgrade. Today, I am not sure if I would have updated the battery of the Ninebot, if such a wheel would have been readily available. It is unfortunate that Ninebot stopped innovation. I think they still have the best looking wheels, which are also very reliable and easy to maintain. Just compare the procedure to change the tire on a Ninebot vs. a Kingsong...
  7. For KingSong, I would recommend to buy from the German "1RadWerkstatt": http://www.1radwerkstatt.de/epages/80603321.sf/en_US/?ViewObjectPath=%2FShops%2F80603321 They offer free shipping for the entire EU, are an official KingSong reseller, and are very reliable. You could pre-order a KS16S from them (no down payment necessary). I have one on pre-order. They told me they are checking and testing every single wheel before they ship it out to a customer. Since they run a repair shop as well, they have all the tools necessary to service your wheel if required. I would not recommend GotWay. Check the forum for pictures of the wire harness GotWay uses in their wheels. They seem to have issues with cables and connectors getting so hot that the plastic melts, causing shorts, cut-outs, and people flying off their wheels. I would not risk that when riding on amalfi coast. I was there once (by car). Very scenic but also steep cliffs in some areas. I wouldn't want to fall off the wheel there... KingSong is known for having the goal of building the safest wheels possible.
  8. So the assumption is that it was a BMS shutdown? If that's true, then I would say the motor controller is not working properly. The firmware has to know what the systems hardware limitations are, and must not exceed them under any circumstances. Why on earth would the firmware decide to overload the power supply and cause a complete and sudden loss of power with the rider definitely flying off the wheel, instead of just letting the wheel lag behind while pumping all AVAILABLE power to the motor to keep up as much as possible? This would cause the rider to tilt forward as the wheel under his feet lags behind, but it would at least give him a chance to react and ride it out. If there is no more power to be had, it's no use to stick to the simple control loop and overload the system up to a complete failure. Controller software needs to allow for errors in wheel balance, in favor of staying within the safe operating area of all its components. Battery voltage and current is constantly monitored. It should be no problem to limit motor power output when battery voltage drops too low or currents are too high, approaching BMS limits. Under normal situations, it is of course better to warn the rider upfront by doing the opposite, which is to drive the motor even harder to overtake the rider and cause the pedals to tilt back, since this will safely slow him down. But if things got bad all of a sudden, there is no more power reserve for tilt back, and no time for beeping, any wheel should keep going at maximum permissible power output and hope for the rider to correct his balance. Exceeding BMS limits is a software error and must be fixed. There is no excuse for this behavior and I don't see how a sudden power loss due to the BMS shutting down could be preferable to any other option. Also, overheating is no reason for a sudden shutdown. I used my NB1 at 35 Celsius outside temperature climbing a steep hill in the woods until the overheat warning kicked in at 70C system temperature. The wheel did not shut down on me while I was riding. Just started beeping and kept going until I stepped off to let it cool down. That's correct behavior. Same thing with trying to climb faster than the wheel can handle. On a very steep hill I climb almost every day, I can go like 7-8kph. Pushing it harder causes it to beep as it approaches its 1.5kW power limit. So the beeps we can configure as a speed warning are one thing, but any wheel should beep by itself regardless of current speed, when power output approaches critical values. The only problem with these warnings may be that there is no time, when a rider causes the system load to change too fast. I for myself see riding the EUC as doing SMALL adjustments to a delicate control loop. Any control loop has a certain feedback delay and needs time to adjust its output to the new situation. So even when accelerating to overtake someone, take it easy, and pay close attention to the wheels response. Ultimately, it is the riders responsibility to stay on top of the wheel, and not the wheels responsibility to always stay exactly below the rider. That's how I see it and how I ride the relatively weak NB1 for almost 2000km now, without any crashes.
  9. Oh yes, pedal dimensions! I don't know why this is missing most of the time. Maybe for Asia, pedals are by far large enough and no one really cares, but for Europeans, they can feel pretty short at times. Ground clearance is related to maximum lean angle, but I agree it should be specified since it's a different kind of property. It would not tell you how much you can lean into a turn, because maximum lean will also depend on pedal width, but it tells you how big a stone or other obstacle can be, before it will hit the pedal (going in a straight line past the obstacle, like in a near hit of something laying on the ground). I added your points to the list in the OP, thanks.
  10. Yes, since power is basically torque times RPM, there can be different motor configurations, all rated for the same power output, but with different RPM/torque ratio. That's what I meant by "motor power alone doesn't tell the whole story". From the power rating, the end user can not deduce what the motor configuration is and how much torque it would deliver at a certain speed. My example about using different motors in wheels rated for the same top speed did not assume same motor power. When I decide on a car or bike (riding heavy motorcycles for around 25 years now), I always look at the torque characteristics of the motor for an educated guess about how the vehicle will perform. I would love to see such a graph for EUCs one day. Maybe legislation in Europe, which is in general pretty over-regulated in every aspect, will demand such measurements in some sort of official approval, to make sure the EUC is safe (as safe as it can be riding on one wheel) in the sense of providing enough torque to stabilize the unit in all common situations. Pot holes will always cause crashes...
  11. I would like to make a case for better technical specs provided by the manufacturer in their data sheets. This would help a lot in making the right decision when buying a wheel. Specs we get right now, like top speed, battery capacity, electrical power sustained and peak, unit weight, dimensions, and estimated range are a good start and there is nothing really wrong with that. But it's not complete. Especially for riders with an eye on safety, additional data would be required to get a picture of how much safety margin the manufacturer actually built into the unit. This is not shown anywhere right now and we are constantly guessing. Additional data I would like manufacturers to list are: Graphs of actually measured available torque (at the wheel, in Nm), similar to what we get for cars. Torque on the Y axis, speed on the X axis. Multiple curves, for 100% and 20% battery as well as high and low temperature. This graph alone would provide a lot of information we are currently only guessing. More data on the battery, like maximum permitted output before the BMS cuts power and the time delays applied (if any), or cell type used for the packs. Maximum electrical power the motor controller is designed for (headroom to overdrive the motor in certain peak load situations). Maximum lean angle (similar to what we get for motorcycles). PWM frequency used to control power as well as MOSFET configuration (how much phases, how much FETs in parallel if any). available negative torque vs speed, i.e., the graph of maximal brake power depending on speed inner and outer pedal ground clearance pedal dimensions There may be more ideas, so I started this topic for people to chime in, and hopefully someone from KingSong, Inmotion, or GotWay reads this and thinks about it. It could help manufacturers to showcase their concern for safety and get credits for using better MOSFETs, better battery cells, or a motor designed to deliver usable torque up to 70kph even though the wheel is spec'd out for 30kph only. I feel that torque over speed is the most important information missing as of today. In a wheel designed for 30kph operating speed, the motor could either barely make the 30kph and be almost out of torque (which would be very dangerous and should not be the case with any current wheel, just an example), or it could have been designed to go 70kph or more, meaning that it still has ample torque available at 30kph. The drop in torque would be much more flat and less noticeable, adding a lot to safety for 'fast' riders. Electrical motor power alone is a hint, but does not tell the whole story.
  12. My Ninebot One E+ is 20 months old and did almost 2000km so far. Mostly riding near top speed, going up and down really steep sections on a regular basis, did some riding in the woods until the overheat warning kicked in, used it in winter at sub-zero degrees Celsius outside temperature, used it on snow and wet roads, in the rain, on sand... No issues whatsoever, no cutouts, no faceplants, but it had to survive some drops in the beginning, which did not cause any problems with the wheel. I guess these units are pretty well built and I would expect it to last for at least another 2000km.
  13. Interesting. I guess since that's the first firmware for the 16" 1200W motor, they take it easy on startup. Not to blow the MOSFETs or cause a BMS shutdown. Maybe they will gradually change to a more aggressive start once they are confident with the new hardware. It's better to do it like this than the other way around. Keep in mind that a motor rated for 1200W continuous output is capable of extreme current draw when it's not moving yet. This is because there is no Back-EMF to work against the 67V applied to the inductors. They get the full load. Once the motor starts moving, the induced counter voltage will work against the voltage applied by the MOSFTEs and thus reduce power consumption (up to the point where the induced reverse voltage equals the available forward voltage to drive the motor, which is the maximum speed the motor can go). In early days, one had to use switchable loads in series with the motor to limit the current draw during the start-up phase. Nowadays, we use PWM to control the amount of power delivered to the motor. The MOSFETs used in the KS16S are capable of up to 1280A pulsed current and 195A sustained DC current (at 25C case temperature), which seems like enough headroom, but the motor controller also need to watch out for the BMS, which could cut power if over-stressed. In my opinion, many of the 'cut-out due to overloading the wheel' reports simply indicate firmware bugs. If the motor controller is working correctly, it stays within the SOA of all components at all times, and there is no reason ever for a BMS to shut down due to 'overload' or a MOSFET blowing up due to over heat or over current. The worst thing that should happen is that the wheel can not keep up with the rider, causing the pedals to tilt forward as the wheel lags behind. Any experienced rider will be able to balance this out immediately and correct for the lag. What can't be balanced out is a sudden shutdown, ultimately caused by bad decisions made in the controller software. I was riding a NB1 E+ for almost 2000km and are in the market for a KS16S as well. Once I get it, I'll report back how it compares to the NB1.
  14. Maybe it draws 18W while you are looking at it with the app, but enters a low power state when sitting ilde. Like a friend of mine who wondered why his washing machine would not finish. Every time he looked after it, it was running - yet, the program didn't finish even after hours. Turned out that the outlet to which the machine was connected was only powered when the lights were on. So when he left the room and turned off the lights, the machine stopped. When he came back later and turned the lights back on, the machine was running... crazy things happen :-) Another likely possibility is that the 300mA reading is just very inaccurate. Power measurements done by the controller board are designed to protect electronics and battery by warning the user about over power conditions. These conditions imply currents of around 50 Amp, which the board needs to handle and measure. To allow for some safety margin, the circuit will be designed to handle even higher currents than that. Now if you expect the board to be able to accurately measure something like 100mA up to 50A, that would be a 1:500 range. Considering that the controller board is not (and does not need to be) a general purpose power measurement equipment, I would be very surprised if it could actually measure power from 10W to 3kW with good accuracy. What happens to the 0.3A reading if you turn the lights on and off? Does it change in a way that makes sense?
  15. I find 23kph a speed I can sustain without beeps or tilt back, but only when riding on a flat and smooth surface, like a new bicycle path. Rough terrain causes beeps much earlier. Exceeding 23kph first results in beeping, then in gentle tilt back. I am using firmware 1.4.0. Compared to earlier firmware versions, I like the current behavior best. Previously I used to get sudden tilt back before any audible warning. Beeping started only when leaning against the tit back. I found that somewhat annoying. It's better to be warned by a beep first, before tilt back actually kicks in.