Chriull

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Everything posted by Chriull

  1. If you ever do something like this again, you can also hide your topic after submitting it - add your additional post without anyone (but us moderaters) seeing it and then finally unhiding it once you finished.
  2. Ist laut Homepage mit 260Wh Batterie - Das sollten dann 16s2p mit 2200 mAh Zellen sein? Auf http://www.eroue.fr/produit/gotway-mcm3-monocycle-electrique/ habe ich den gleichen mit 340 Wh gesehen um 549. Der auf electro-sport.de wird derzeit um 589 angeboten... Habe aber keine Ahnung welche Batterien beim MCM3 verwendet werden, noch kenne ich den französischen Verkäufer... gerade mehr Wh sollten normalerweise eher besser sein?
  3. It shows ni voltage value? then you could try some third party app like wheellog/gyrometrics or the other one i can't remember the name. They all support inmotion v8? or you order an charge doctor and can monitor the charge process and get numbers for the battery capacity.
  4. That's about one of the worst things to happen to liion cells. (Besides letting them fully discharge) according to http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries liion cells stored for 3 month at 60 degree celcius just have 60% of their capacity left! Hopefully it was not as hot in the garage - at least not at night time... The bms of the e+ has a reverse voltage protection diode at the charge side - so there is no (valid) voltage to be measured at the charge port. But one can monitor the charging process with the chargedoctor or something similar. maybe some optical inspection of the batteries would be a good idea after this treatment? the strange behaviuor of the charge state displays (led, app) could be a sign of bad cells. Unfortionately there are quite some reports/discussions that the ninebot e+ Bms does not really balance the cells ;( but a try should not hurt - maybe it works... Should be the safest way - or opening the pack and taking a closer look at the cells before? anyhow - this pack should be treated with special care - beside no supervised charging also charging only in some safe envirome could be recommendable.
  5. Just got the wheellog data from another rider of an "high-speed crash" he had with his KS16B some time ago. (1) He heard no beeps and there was no tiltback - they wheel just stopped supporting him... The speed and current (dark blue line - IMotor KS16C) in the limit diagram: One sees nicely how he "hit" the motor limit (violett line) at around 27 km/h - 36A and continued on this limit line until about 36 km/h. So tiltback would have started at 30 km/h - but not anymore possible since the motor was at it's limits. It just should have beeped by then - but quite imagible that this was not heard anymore after beeing in the process of falling and seeing the street coming nearer... The wheellog data (speed,voltage,current,temp - the rest is calculated..): I had to adjust some motor constants a little bit to get the calculated limit line to his measured one (my first try was some real rough estimation (http://forum.electricunicycle.org/topic/7549-current-demand-versus-battery-voltage/?do=findComment&comment=106424)) For the internal resistance of the battery pack (16s4p LG MJ1) i have now 0,23 Ohm instead of the calculated 0,148 Ohm. I got this by minimizing the "ripples" of the calulated no-load battery voltage (U Batt 0) as low as possible... The still nicely seeable peaks on U Batt 0 are from the regenerative braking - the motor current is always measured as positive value and the used formulas are not right for the "regenerative" case.) R Coil was changed to 0,37Ohm and kv to 1,41 V/km/h. (1) he "just" got some nasty road rash/bruises and recovered fully. Ps.: Had some interesting reading about that the coil temperature has quite an influence on the motor charateristic - copper increases it's resistance roughly about 0,4% per degree celcius - so between 20 and 80 °C is a difference of 24% in resistance of the coils! And this resistance is one of the main parameters for the "steepness" of the limit line. PPS: he refused to repeat this with his KS16S so i get data for our new wheels...
  6. This milage should be no probs, if the pack got balanced from time to time. Whats the battery voltage the app shows after a full charge?
  7. I would not buy any of these - they have too weak batteries. these are both 2+ years old wheels... There should be better wheels in the market for almost the same price. If it has to be one of these then the ninebot c+ is the clear favorit - more robust and better "technology".
  8. The voltage from the graph was delivered from the control board and seems fine?! No tiltback is just because the motor could not accelerate enough anymore. Done. Somehow imgur downscales pdf's... ;( Just one point is not clear to me till now - he accelerated with ~3 m/s² before the incident. The calculated values for the limit graph would suggest just 1,2-1,4 m/s² (between the orange and black line)- wondering what went wrong with the calculation of the needed power/current...
  9. if each cell (cell pair) is and can be charged to 100% individually the problem is solved. Maybe just temporarly if there is a big capacity difference. Could be that the original charger is not anymore able to balance all cells to 100% - depends on the capabilities of the balancer circuit of the BMS. Maybe the cells were just never balanced and this was the reason that the cell voltages "drifted" too much apart. One real balancing and it could work fine again. Maybe the cell is just at the end of the lifespan and has to be replaced - can imho not be said without some trial...
  10. The hall sensors should be the next big question mark - if they don't fit nothing works. Also their positioning could be different with different motors? Also the motor windings could be connected as "star" or "triangle" (also i never heard of a "triangle" bldc for euc's - but who knows...) Chances could be quite high to just dump money if one tries this... But one could buy a suitable motor afterwards (if the mb survives)... Adopt the shell if it does not fit, etc...
  11. That's another huge advantage of packs with many cells in parallel - each cell gets less current drawn! As you maybe know the dampfakku.de discharge graphs - the more current is drawn from a LiIon cell, the less real capacity it can provide. I am really looking forward to the first Panasonic 20700B cells used in 2-4p packs - or even better cells like this until this will happen... Also on http://airwheel.ru/test-monokoles-na-dinostende/ is nicely seen how "cell quality" influences the wheels performance (V8 Vitaly vs. normal V8, ACM Litcher vs. ACM 680, KS18 680 vs KS18 1360, KS16 340 vs KS 16 840)
  12. You could make a "first" rough test if your bwheel could (maybe) be upgraded - measure the lift cut-off speed. (and hope that it is not limited by the controller - imho that's normally not the case). For the KS16 for example the maximal safe riding speed is about 2/3 of this lift cut-off speed. So for your BWheels motor beeing able to provide 20 km/h riding speed you'd need roughly about 30 km/h lift-cut off speed. For the KS16B/C going 30 km/h it's about 47 km/h. (45 measured with almost full batteries) This should be one of the main parameters. You could maybe have good luck (if this lift-cut off speed is in the right range) that a 20 km/h microworks motherboard works for your motor. But there is a second important parameter - the coil resistance. Don't know how and if this influences the needed controller. From looking at the motor one should not see anything - there are no tables to compare them. Also i don't know if this above mentioned two paramters are already enough to choose a suitable motor...
  13. Yes - that's something all BMS controllers do since "ever" - like the controller mentioned in http://forum.electricunicycle.org/topic/2247-decrease-charging-time-5a-high-current-charger-mod/ for the ninebot e+ already had this "functionality". But this voltage threshold can be programmed and maybe is choosen too high from Inmotion? But anyhow - a bad cell has to be replaced. With a working balancing this should only happen with a "very old" pack. Don't know if Inmotion wrote in their manual about the importance of balancing and maybe also checking the voltage in the app from time to time after a full charge - especially if the wheel starts to feel "weaker". Or as written before, the charging stops prematurely.
  14. i assume he means he has both - a ks16 and a yellow bwheel?
  15. Thats the same with all other wheels except GW, which have no "protection" for the discharge side. that problem arises only with older packs, or if one has bad luck and got a not so good cell from the manufacturer. Also this should (normally) start by the charger shutting off prematurely, because some of the good cells start to get overcharged. One could notice a shorter range and lower performance. could be that the cells never got balanced (too low charger voltage or the charger never left plugged in long enough?) the v8 also has "only" a 2p pack - so the cells age faster and get more burden - thats why i got my ks16 with a 4p pack, and by now they are not abailable anymore with less.
  16. Which firmware version do you have? Starting from standstill against a burden could destroy your wheel! The KS has a more powerfull motor than the ninebot - try it with a little bit of speed and you'll notice the difference. KS (and also GW imho) had some probs with "starting the wheel up" - they have some current/power limiter implemented, so the wheel cannot overpower/fry the mosfets but this caused sometimes with some firmeware versions that they wheel did not "start well from standstill" Yes - have the same memory from my ninebot. Seems he has some better firmware algorithm for controlling the motor at low speeds. Have no idea - but that should not be the reason...
  17. This is a resistor - if one googles for "Ks-18A motherboard" one can see nice pictures of it alive. Could be "red-black-black-gold -- brown"? - Cannot really 100% identify the colors on the pictures ;( If you can you could try replacing it - but there are chances that this is not the only part that died... Maybe also some ks18a owner is around here and can help identifying? As the google resulsts show, you could still have chances to get a new KS18A board from some shops/aliexpress/.... Basically you could ask everyone selling KS if he still has some stock...
  18. Fortionately he had a mishap - negative currents are still available for the KS16S log It's now just a If (Current>3,2768) then Current = (current-6,5536)*100 else Current = Current*100
  19. Could be - there was a topic not too long ago of one member wanting to replace the broken connector on the motherboard for the wires coming from the motor. He wrote something of a "missing" wire he could not track clearly? Maybe there is just one wire going to the motor connector which is there somhow "encoded" (chip, resistor or whatever...) inside the motor plug?
  20. The power consumption of the app is just a house number - at low speeds it can be easily twice or triple of the real value. +1! also on a straight road once when i did not watch the surface there was a small ditch which made me "fall" forward - i was already sure that i have my first high speed faceplant on asphalt, but the ks made it to accelerate again under me so nothing happened other then a bit of adrenaline! No. Beeps are Only for slow speed overpowering, overheating and the fixed speed alarms. Thats very easy to implement, needs almost no cpu resources and would be a real usefull alarm. a 30 km/h alarm and tiltback is extremely conservative with full batteries and useless if one accelerates a bit more on not so full batteries - then a below 30 km/h "cut-out" is easily possible. Without any beep or tiltback. @ubertoad- maybe thats my strategy to stay safe: the faster i go the less i accelerate!
  21. As far as i know no wheel has until now warnings (beeps) before it reaches the torque limit. Somehow i managed it to stay well below the limits ( if you look at the blue dots in the graph). Also like it was written around here with the power abilities of the modern wheels and the pedal length (lever) it is hard to reach the limits? i don't know if i have a certain strayegy - i just don't want to faceplant. Maybe its something one learns over time - maybe at one of my next uphill rides i have my first real faceplants... you could just log your rides with either wheellog (android) or Gyrometrics (ios) and put your data into this limit excel sheet and check after your ride in which "regions" you where riding. ps.: gyrometrics has a small fault in the actual version - for ks it shows the current by the factor 100 to low.
  22. Just an overheat cut-out is power related (or cut-out due to wires/connectors melting or mosfets frying). then there is the overcurrent cutout of the bms (which gw does not have) and which does not really happen anymore with modern wheels. and then is the last reason for a "cut-out" when one hits the motor limit - thats the most counter intuitive. This is not a real cut-out but an overlean - from a certain speed on the motor can only deliver decreasing torque, so is not able to keep one upright by accelerating. If you take look at the graph ( motor current in A (which is proportional to motor torque) over speed in km/h): And look at the line "current for incline 5 degrees and acceleration 1 m/s^2" (some grey-magenta color) - if you imagine one "rides" along this line and accelerates. If the speed reaches one of the "max limits" lines - depending on the actual battery voltage - then the motor suddenly cannot deliver the needed torque (not enough current possible to flow) anymore and if the rider does not brake/balance himself immedeately he faceplants...
  23. We have P motor output = I motor * U Back EMF = I * kv * v and P mechanic = M * r * v so I * kv * v = M * r *v and I = M * r / kv. or how it is imho normaly defined: P motor = I * kv * omega = P mechanic = M * omega -> I = M / kv ( with omega as rotations per second)
  24. Just noticed this shortly - i'm a slow updater... . It's a simple "double division by 100" which happened to @Paco Gorina... just opened him an issue on github. unfortionately he inhibits negative currents for Kingsong - seems that i have to power up my mac and try an own version once i get my Ks16s. I absolutely want and "need" the signed values! Regarding power: All apps show invalid numbers as power: the wheels send motor current and battery voltage, so the power values are always too high. By this the energy numbers are invalid too...
  25. They are as vulnerable - there is no security concept. The good thing is that gw, ks and the others cannot be remote controlled as a minipro. Don't know if an attacker could start a firmware update or calibration while one is riding - should be prevented by the firmware, but imho noone tried this by now... (as also the power button is disabled while riding...)