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Chriull last won the day on December 3 2016

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About Chriull

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  1. Peak power’s peak duration?

    Mostly. At low speeds by current limitation nominal output power cannot be reached and/or can/will lead to overheating. At higher speeds once the limit curve is reached nominal output power also cannot be reached anymore while accelerating... (for the short time while faceplanting) Peak power can be reached at exactly the speed where one of the constant power lines just "touches" the limit line. As the slope of the lines is determined by some factors and the constant power lines are also "distorted" by some factor the ratio between max speed and the speed at which peak power can be reached should imho not be some universal constant (once i get into the formulas again i could double check this - maybe it is some constant? Both factors could depend on each other?). It will depend on the wheel design and also the wheels operational state (copper temperature, battery state, etc). But in the above example it seems to be around 50% max no load speed. The power shown by the Kingsong App (and all other apps) is just some number - the slower one drives, the more the value is off (too high) (http://forum.electricunicycle.org/topic/7549-current-demand-versus-battery-voltage/) I don't have any idea how the real nominal and peak output powers for the used motors are. Nominal Output power could be "reused" for the EUC nominal power by the manufacturers (would make sense to me). Peak output power for an EUC is determined by the (current)torque over speed limit for each actual battery state and not by the motors maximum output power (at least i'd hope that the motors max output power is not really reachable within the torque-speed limit of the EUC - there should be some safety margin for a sane design) Power = torque/radius * speed = constant * current * speed So the constant power lines (reddish lines) are current * speed = constant (1/x lines)
  2. KS Firmware 1.26

    Just discovered that 1.26 is available for KS16B/C. Did not remember reading something about this around here. Is it new or did i just miss it? Anybody already try it and knows differences/probs?
  3. Peak power’s peak duration?

    If you look at (Taken from my http://forum.electricunicycle.org/topic/7855-anatomy-of-an-overlean/ topic) for an KS16C. There are the dark red (800W), medium red(1200W) and pink lines(2200") which show constant power output. The grey areas are (depending on the battery voltage) the not reachable areas - The motor cannot provide this much output power of example the pink 2200W output power line. Along the blueish limit lines (light blue - highest battery voltage till dark blue - lowest battery voltage) one could imagine the corresponding constant power lines, which are reachable within this limit. The more the battery voltage drops (by discharge and temporarily by "internal chemical processes" but not by normal voltage sag over the internal resistance - this voltage sag by internal battery resistance is already regarded in the limit lines) the lower this limit line and by this the maximum reachable output power gets. So in this example the KS16C will stay "forever"(unitl EUC shuts of in because of low battery) in the range above nominal output power of 800W if one stays in the speed range above approx 14 km/h. At lower ranges the current is quite high and could/should lead to overtemp situations while asking continously for this amount of output power. Edit: PS.: please ignore values for the violett lines for now (current for incline xx and acceleration of xx) for now - i am not sure about their scale! Edit: The limit lines are determined by - The "no load" battery voltage which specifies the max no load speed at one end and - coil resistance and internal battery resistance at the other end. coil resistance can vary by something around 20% depending on the temperature of the copper in the coils and also battery resistance can vary depending on load/age/temperature/etc... - the 80 A limit is choosen arbitrarily - don't have any idea of the real value, but fits in the diagramm and somewhere around up there should/could be some limiting...
  4. German Discussion Group

    Hoffe die Verletzungen waren nicht allzu schlimm! Tlw. hängen Stürze/Unfälle vom eigenen Verhalten ab - tlw. "passieren" sie einfach und können nicht verhindert werden. Auch die "Art des Fallens" kann wohl beeinflußt werden, aber es besteht immer ein Risiko, dass man überrascht wird und/oder unglücklich fällt. Also, je besser deine Schutzausrüstung ist, desto weniger sollte passieren im Fall der Fälle, und je langsamer man fährt, desto geringer sollten die Auswirkungen eines Sturzes sein und das Risiko das man überhaupt stürzt. Neben den absoluten Geschwindigkeiten sind auch die relative Werte je nach Einrad wichtig - die Sicherheitsreserven, die man dem Einrad läßt ("Abstand" zum Drehmoment über Geschwindigkeitslimit in Abhängigkeit der Batterieladung). Ist also eine rein persönliche Entscheidung wieviel Risiko man in Kauf nimmt, wieviel man übt und wie man sich schützt. Wird wohl für jeden eine Auf/abentwicklung sein - solange nichts passiert und man erfahrener wird fühlt man sich immer sicherer und wird risikofreudiger, nach einem Rückschlag fängt man wieder vorsichtiger an bis sich die Sebstsicherheit wieder aufbaut... Oder man fährt einfach durchgehend vorsichtig oder das ganze ist einem sowieso egal - hauptsache man hat Spaß (solange es geht ). Ich fahre immer mit Handgelenksschützer, so gut wie immer mit Ellbogen und Knieschützer und ohne Helm. Fahrradhelme decken imho viele Einradunfälle nicht ab - und Vollvisierhelm mag ich einfach nicht zum Fahren nehmen ... ändert sich vielleicht nach meinem ersten ordentlichen Crash...
  5. Hearing loss while out.

    Imho there are earplugs that leave some frequencies with less dampening, so one gets not absolutely "deaf" and can hear cars approaching, etc... 120 db are the pain threshold. So if it hurts or its getting extremely discomfortable you know you reached about this 120db. Strong traffic should be around 80 db according to tables. Imho 85db is too much just for driving 10 mph thats maybe the solution. Its could be the noise created by the wind at the opening for the phone microphone? As having a telefone call with someone in a windy enviroment - one hears mostly only this wind induced noise and not the voice. So for measurements one should try that the microphone is not held directly into the airflow. You could also check the values shown from your app against some described sceneries in noise level tables.
  6. 18L Group Buy?

    Maybe just the VAT could pose some problem - hopefully it stays below the declaration threshold for one time "business" for private persons... ... Or can be ignored without too much risk to be caught by the tax authorities 😎
  7. Goin down a hill with a wheel

    Yes, one needs the same energy to break as it was build up by the system. As the kinetic energy goes with the square of the speed its "much less" at lower speeds and zero at immobility. By regenerative braking real work is done! Beside the real heat losses (power dissipation) there is real power consumed by the battery for charging. And as the voltage generated by the motor is transformed "upwards" by the mosfets in combination with the motor coils, the braking power ("current flowing into the battery") can be nicely controlled. With normal (bike) brakes you also do not need to put energy (besides pressing the brake shoes) into the system for braking. No matter at which speed. So these are imho no arguments against regenerative braking possubilities. The main difference with electric motor braking by putting a load at the motor output (regenerative braking is just a case of this) is that only an asymptotic approach to a speed of zero is possible. Beside this intrinsic limitation the voltage transformation will not be feasable below some specific speed - there is just not enough voltage generated by the motor to transform it up to a little bit above battery voltage. Then there is just another mode of motor braking left, that switches the polarity of the voltage put on the motor. But this needs quite some power from the battery and leads to high power dissipation in the motor coils. So this cannot be used at higher speeds. (Or speaking in terms of foc (field orientated control) putting the vector of the commuted magnetic field "behind" the vector by the motor generated field - very imho, one of the firmware guys would have to confirm this...) In my opinion this last kind of braking just happens at the very very very end of a braking process and is "hidden by/transforms smoothly into"(1) the normal balancing process that happens continously. Unfortionately the sampling resolution of the data sent by the wheels and logged by wheellog is not high enough to clearly see/follow/analyse this "mode" switching (or at least i have not found an real unambigous proof of this in my logs. Edit (1): while at higher speeds balancing just needs some slight speed(acceleration) changes, at very low speeds balancing has to change the direction of the wheel and by this at some point this "polarity change braking" has to occur?
  8. Goin down a hill with a wheel

    Halogen bulps seems to be a nice solution. Once a member posted here a diy solution. But imho no follow up after the first tests... Edit: found it:
  9. First wheel for commuting e+, s2, v5f

    Should be both nice wheels. Main difference is imho weight vs range... Imho the ks16b was aailable with many different battrry configurations. So this could relativate the decission again.
  10. Fan Cooling questions

    With my ks16 c and s it is not hearable (by me) while driving. If its active at standstill in a quiet environment one can hear it. btw: ks sends the fan on/off state - would be a nice addition for wheellog to log this additinal data I have never heard or read about a ks (or other brand) fan failure. would be interesting to know if this could lead to mosfet problems or just to earlier overheating alarm/tiltback/shutoff?
  11. Kingsong 14D speed issue

    As it seems with firmware 1.05 speed reduction starts gradually at 50% to reach 12mph near 0%: Imho no 420Wh wheel could make you happy. average consumption of wheels is (as far as i remeber) between 10-12 Wh/km for slow and easy driving to somewhere above 15-17Wh/km for max speed cruising/inclines/... so just 80% charge of the 420Wh pack leaves you with 336Wh. This give you ~22km range at 15Wh/km and by this about 1h riding time at some average speed of 20km/h. (Or accordingly less time the nearer you get with you average speed to max speed). and this leaves you just 336-420*50%=126Wh at unrestricted speed... so your choice should be at least something like the ks14s with a 680Wh pack and speed restriction starting at 31,25% Edit:ps: the 15-17 Wh/km are maybe the lower range for ambitious driving:
  12. I'd also see "our" responsibility in "educating" the EUC drivers - giving them a chance to understand whats happening why, so they can take their personal decision. Also the user manuals provided (and homepages) by the EUC manufacturers should be the first instance to explain the mechanics and limits/dangers of EUC riding! Many EUC Riders come here first time after they already had an accident/incident. Some nice, easy to understand, pedagogic valuable, explanatory article about overlean (torque speed relation), overvoltage cutout while regenerative braking, etc as a sticky first fat topic in the general forum would be nice. Imho that's quite about all that should and could be done here? I am no friend of too much restrictions by the forum rules - once one starts, where to end? After the dangerous apps EUC's without or with deactivatable tilt-back/alarms are next? Then each EUC which drives faster than 15-20km/h? ... Such an article could also be linked/copied by resellers ( @Jason McNeil? what do you think - that should not really be bad for the business? At least not in the long run!) and could be presented to the manufacturers to be put it into their manuals. Unfortionately i'm not really able to provide light & easy understandable explanatory topics... No. But partially distributed and this forum provides a platform for "promotion"/distribution. Since already US lawyers were mentioned - i do not have any idea about the legal situation, but sincerely hope that this could not inflict any responsibility for @John Eucist or any US Moderator.
  13. Music?

  14. What about firewheel?

    Thats the generation before firewheel...
  15. What about firewheel?

    Some used new generation wheel? Is there a market for second hand euc‘sin greece? Then one it fould be just ik for one direction. also if i remember right from @esajs reports firewheel has no tiltback (as it can be turned of with gotways?), so you have to be carefull to hear and follow the alarm beeps, so you don‘t overlean and faceplant by reaching the max speed for the actual load of the wheel.