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Chriull

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Everything posted by Chriull

  1. That's a pack of 16 cells in series (16s1p). The two connectors (11 and 6 pin) are the balancing wires. Connected to every cell - 16 cells give 17 wires. Maybe you can figure out the sequence by looking at the mainboard?
  2. The low pedals give the "easier" feeling in the beginning and by the better "leverage" make the wheel more responsive. But one gets used to the higher pedals quite fast - and they have the big advantage to get over obstacles without falling and much better "cornering" (?driving curves?) performance! So every EUC driver wants high pedals, although they need some experience. Imho.
  3. Cut offs is a very ambigous expression. A "real" cut off happens if something in the wheel "cuts off", like a fried mosfet, molten motor cables causing a short circuit, in earlier times a BMS cutting off, CPU shutting down, etc... Mostly it's just an overlean - one just aks for too much torque, which the motor(wheel) cannot deliver at this moment. These graphs could about somehow very roughly correlate with an MSX 84V/100V. So a Tesla could be not too far from this pictures (just having less speed by beeing a 16 inch wheel instead of the MSX beeing 18 inch wheels, if they used about the same or a similar motor). This shows the physical limits of EUCs. They can only operate within the grey area (dark grey in this example for the 84V Version, light grey the "extension" for the 100V version) How to "use" this graph: One knows the speed at which one is going - so one can make a vertical line at this speed and sees by this how much of an current the wheel can "push" through the motor at this speed. The current is directly proportional to the torque the wheel delivers. So one sees for each speed on is riding how much torque the wheel can deliver. What is torque needed for / what "uses up" the torque: - air drag - by the square of the speed one is riding - friction: Of tire rolling on the road, the motor axle, etc... - acceleration: torque needed for acceleration is directly proportional to the acceleration and the weight that's getting accelerated. - driving up an incline: Is like an acceleration - depending on the steepnes, one is accelerating "against (parts of) the gravitation" As comparison the same chart for empty batteries: Unfortionately i don't really know, would be interesting - so please if one can confirm or set this right?! Imo GW let one enable or disable some fixed speed alarms? The speed at which they occur cannot be changed? The tilt back speed can be freely choosen up to some maximum value? As reported (in this topic, afair) the third alarm starts at 80% maximum speed. (whatever maximum speed means exactly...) If you look at the above graphs, the real maximum speed (no load speed) is directly proportional with battery voltage. So at full battery (4.2V per cell) compared to empty cells (3.3V per cell) it is ~79 km/h vs ~63 km/h. And 4.2 / 3.3 = 79 / 62. As the alarms are "just" speed dependend, they cannot warn safely from an overlean. If one is near an overlean depends on the speed and the burden (acceleration, incline, wind drag) of the wheel. Additionaly the faster one is going, the less burden the wheel can take. It's not "under the limit" - with an overlean one just "goes along the limit" of the wheel, as shown in the graphs above. For more detailed infos about overlean take a look at There are the logs of a KS16B "perfoming" an overlean below tilt back speed... Hard to answer - but mainly the faster one drives the less one is allowed to "burden" the wheel. So at high speed low accelerations. And decreasing the speed before going up an incline. At low speeds the prob with the high power wheels as the Tesla is, that they can fry the motor cables. So for instance @Marty Backe set with wheellog an 90A alarm for his Gotways and tries to not get that alarm triggered going up inclines. So his wheels stayed (mostly) safe... Yes. But as written above - this alarm can also come too late... ... but on the other side, one can pass the 3rd alarm (best on some slight slope going down (?decline?), without headwind) accelerating very slow and carefull on a "perfect" road easily. That's how many GW drivers go for high speed records - and make high speed faceplant records if they try a bit too fast....
  4. Some (technical) thoughts regarding MSX 84V (20s6p battery configuration) vs MSX 100V (24s4p battery configuration): Assumptions: - both wheels have the same motor - one Li Ion Cell has an internal resistance of 0,04 Ohm - the motor coils (2 of them in series, as they are commuted each time) have 0.3 0.2 Ohm ohmic resistance (this number is very wildely guessed - could be anywhere else in very about this range. This is just assumed to have some numbers to work with!) - 60 km/h no load speed for 84V -> leading to a kv of 0,714 km/h/V Edit: (1) - ~78 km/h no load speed for 84V -> leading to a kv of 0,93 km/h/V - contact/wiring and mosfet resistances are not considered - there is a current limit at 120A (from an old post of an gotway representative) Internal resitance of the 20s6p battery: 20 * 0,04 Ohm / 6 = 0,133 Ohm Internal resitance of the 24s4p battery: 24 * 0,04 Ohm / 4 = 0,24 Ohm The maximum torque over speed diagram (operational limits of the motor) are then defined by the maximum no load speeds on the x-axis: 84V * 0,93 km/h/V = 78.5 km/h 100.8V * 0,93 km/h/V = 94.2 km/h On the y-axis (current == torque) the limit is set by the internal resistances and the Voltage (I = U/R) - the "no speed" (short-circuit) current flowing: 84V, 20s6p: I = 84V/(0,24+0,2)Ohm = 252 A 100V, 24s4p: I = 100V/(0.133+0.2)Ohm = 229A So with the abovementioned assumptions the 100V version has more torque and speed in any case. (But this could change with different values for motor coil resistance and current limit, which are just guessed) But, there could exist a point in time, were the 84V Version "overtakes" the 100V version torque wise by having a higher battery capacity (slower voltage decrease) ... if one drives long enough ... But although could not be - did not look at this in detail... Edit: Unfortionately i took the numbers for no load speed from the wrong row and got the Z10 numbers instead of the MSX 84 numbers ;( The MSX 84 has about 78 km/h at 84V! ... not 60 km/h!... So i changed all the number above and the charts accordingly. I also took now 0.2 Ohm for the two motor coils in series instead of the 0.3 Ohm (this value was still afair from an "old" m3s - with the higher power ratings this could/should decrease a bit the coil resistances? Or not - have no idea )
  5. That's exactly what i meant with @YYY - if you can get such a fan (1) i'd cancel the noctura fans and go the way with the axial fan! (1) here a link to one product https://www.ebmpapst.com/en/products/compact-fans/radial-compact-fans/radial_compact_fans_detail.php?pID=54111 (just as example - as written above you won't get them in HK...)
  6. That's one of the meanings of broken - not working. So it's perfect (imo) Yes, they have a good reputation!
  7. Lol - and one should not forget to caress ones long hair cat often inbetween Ps.: To write something usefull too - i like to use the foam pieces/plastic bags from the PCBs as underlay, as they all should be (a bit) conductive to prevent static electricity.
  8. Interesting. I have never heard here any report of a broken fan. But i am not too much into GW (just reading here - owning none) - maybe i missed reports? ... or maybe the seller wants to earn something extra? I like Pabst fans - but they could be hard to aquire in HK. And unnessecary expensive "over there". Any nice brushless fan with good (ball) bearings should do. From the computers there should be many available with nice rotors (good efficiency for airflow, noise) More rpm mean beside more noise higher stress (less life expectancy) for the mechanical parts. So just as much as necessary . Afair from computers the "main" fans blow on the heatsink to get there rid of the hot air efficiently. I like the setup in my KS16S - an axial fan blowing into the gap between mainboard and heatsink.
  9. @Mono afair always gives the tipp to turn the tiltbackspeed down with the app so one can test tiltback at low speeds! Tilt forward, especially as shown in your video is a "system fault". Maybe your wheel needs some recalibration? Or just the gyro chip has severe probs? Wheel behaviour while lifted has (not really) anything to do with any tilting while normal riding. What you feel as "tilt-resistance" are the "gyroscopic effects" of the (accelerating/decellerating) spinning wheel. That the wheel tilts forward after this once you put it down, is again a system fault/gyro problem.
  10. I have no special ESD equipment and also build up some computers and similar things successfully. As you said - one should stay away from carpets and similar(and maybe not wear 100% synthetic cloth), additionally I "ground" myself before starting (at some grounded metal chassis or the ground "pin" of a socket. And then, imo the most important part - one should only look with the eyes and not with the fingers! I've seen many people saying "look what's this" and in the same moment they touched the mainboard/graphics card/etc... All the "sensitive" PCB can be nicely held just at the outside cirumference, preferably there places with some ground planes (near the holes for the mounting screws), etc. imo many small (some maybe important, some not so..) points that happen just subconsiously by beeing careful. EUC mainboards can easily handled with just touching them on the aluminium heatsink - no contact or even getting near anything sensitive is necessary... Ps.: And since most/all EUC mainboards have quite some coating they should be relatively safe/unsensitivy anyways...
  11. Yes. Or you hope on your good luck that no or not enough "hot glue" was used with your board.
  12. You can use google to find reports here by typing site:forum.electricunicycle.org your search term and get experiences posted here from our members regarding these shops. Afair grenn fashion teavelling shop always had a good reputation, but lately messed up with some customers. From wheel tech i can't really recall anything ..
  13. Welcome @ojek! According to ewheels.com chart with recommended weight the selection is small: Maybe the Tesla coild work out pricewise?
  14. For the battery voltage you can take the reported values from the app. Or measure at the discharge side. The values are unfortionately a "bit" inaccurate, as written above. You can also compare this to i personally would trust the readings of the charge doctor - @hobby16 calibrates the with an precission voltmeter. Although this calibration can drift over time. You can take a look at your multimeters datasheet and look what accuracy could be expected. Once you know which voltage is right, most chargers voltage can be adjusted. It's quite often the case that charhers are (getting) misadjusted. Don't remember if there was not lately the same description for the ewheels charger? Or if its still under warranty and too much of maybe get a replacement?
  15. One has to compate Wh with Wh. The different factor in range is about the same factor as of the Wh. One cannot compare Wh with V.
  16. As it seems the nikola uses more current (at least reports more) for its "zippy" performance. This could make him less perfect for hillclimbing (more heating up, more battery consumption)? So maybe a MSX with 18 inch could fit you better? High speed would have been a main point for 100V. Imho just theoretical. If they have the same motor, one has a bit more torque at each given speed. So at your "safety" speeds this should not really make any difference. But the 84V version afaik comes with bigger batteries - would give you more range. Going uphill consumes batterie, also riders weight. Not with the same motor. If so the 100V version could create more heat, because it can be ridden with higher speed/torque combinations than the 84V version. If driven the same way they should behave (about) the same.
  17. Since i just posted a bit about charging here a link: That was imo wrong- the CV phase is only longer with >~0.5C charging....
  18. If you take a look at the charging graph at https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries, you'll see that with a 1 C charger it takes about an hour for the first stage (constant current =CC) and then about 2-3 hours for the second stage (saturation charge, constant voltage = CV). The second stage ends somewhere once the current reaches around ~100mA. If one charges with less than 1C the first phase gets accordingly longer (0.5C ~2hours, 0.2C about 5 hours, etc) The second phase stays about the same - maybe a bit longer for the faster chargers. The more current is used while the CC phase, the higher the cell voltages are "pulled" up while charging (by internal resistance and the chemistry of the cells). So if the charger stops at the "80% voltage" the battery goes back to a lower voltage after charging the more current was used. If one charges the battery with a fast charger, the battery gets pulled up a bit more and reaches by this the CV phase with a bit less charge than with a slower charger. So the CV (saturation) phase should take a bit longer. Regarding voltages, charge % reported by the wheel and shown by some chargers: that's unfortionately everything a bit inaccurate. 1% of 67,2V is already 0.67V and accuracies way below this for voltage measurements are "hard" to reach/should not be expected for "cheap" chinese products. (Or generally not for anything but "professional" measurement equipment) Charge % are additionally calculated in a way that there is a wide range for 100% shown. So it's best to stay with the voltage reported by the wheel! (Taken some time after the charge, so the voltage can settle to a value really correlating to the charge) So to compare chargers one should charge the batteries the full cycle until the charger shuts down at this roughly ~100mA. So for and empty battery ~ 1/C hours plus 2 to 3 hours. After this you can compare the voltage values reported by your wheel. Unfortionately its not uncommon that some chargers are just a bit/way off. PS.: How to get the C Value: Your 67.2V wheel has 67.2V/4.2V (4.2V is max cell voltage) = 16 cells in series. So one divides the Wh of the pack by this 16 cells in series and then divides it by 3.7 (nominal cell voltage). That gives the Ah of the paralleled cells we need. Now this C value is charger current divided by this Ah. For example if you have the 1508Wh KS18S it has 1508/16/3.7=25.5 Ah. So C= 2A/25Ah=0.08 for the 2A charger. Meaning 1/0.08 + 2..3 h ~ 14-16h for a full charge.
  19. Sorry - how could/does this work out? Afai read here in the posts braking just regenerates one battery back instead of both - so much potential is wasted. I could'nt see any correlation with forward torque?
  20. If one charges shortly before a ride until it's showing 100% there would be no (charging.) Edit: balancing. I'm not sure - but imho changing to green is when the charger shuts off? So the balancing part is done. ... and obe has reached the full voltage after unplugging the charger...
  21. Balancing happens at the constant voltage part of the charge - the last and longest part. So one should not go for 100% charge reported, but full voltage!
  22. One would need to really split the cells from one another - like putting a mosfet inbetween the parallel cells. For measurement they would cut the connection, while riding the connection is established again. Would be a "mess" to wire such a pack up, imho reliability would decrease greatly - so one could monitor the state but decrease overall safety? Afaik the Teslas have some systems like this to disconnect some bad ?strands" from the battery system so they cannot disturb the other cells. But imho making such a thing on a per cell basis is in no way economical. Such a splitting up and isolating one not as good cell or just identifying it by monitoring would work out - also imho by now not economicly feasable. Also normaly the cells are tested and presorted by the battery manufacturers - so they should perform good in packs. Just from time to time it happens that one "bad"/not so good cell slips through into a pack. This one then dies together with their paralleled cells. But this is "bad luck" (cell got somehow damaged or slipped through the tests) or some manufacturer who used unmatched cells. For this cases the battery degradation happens quite "fast" and are (should be) covered by guarantee. Normal aging just happens that one parallel cell pack is a little bit weaker than the others - this is the one who gets discharged and charged most (gets highest and lowest voltages) and by this everytime a bit more stressed as the other cell packs. After enough time (charge cycles) all cells of such a paralleled pack are just dead. No need to know individual voltages or other state... Resplit your post again to this topic... no.
  23. Ups - sorry too from my side - i did just look at the pictures and not get, that is a new case of a new replacement board.... Maybe one can see something once @Jim Martin posts the pictures of the heatsink and the thermal pads... Somehow the mosfets have "something" on them - one sees this "pointy pattern" reflecting from the flash, most "again" on the blown mosfets?! - or is this just that the had the best angle for reflecting?
  24. This is for battery pack configuration like the 20s3p - meaning always 3 cells in parallel and 20 of these blocks in series. All the packs of 3 cells in parallel have to have the same voltage - they are fix connected. So if one measures the voltage of one, its exactly the same voltage as the other 2... So for example for such a 20s3p pack one needs to monitor the 20 packs of 3 parallel cells - measure 20 voltages. By this one knows the voltage of all 60 cells.
  25. Would be my best guess to. A bit could be the "glue" or whatever reflecting the flash, but some pieces definitely look like molten metal. This should come from the ?inside of the mosfets?, the vaporized mosfet leg and some vaporized solder. So all "post mortem stuff" It's overheating by beeing thermaly insulated from the heatsink. @Phil McLaughlin made a nice test series shown in his youtube videos (i put a link to both in the first post of this topic). Without a proper cooling this Mosfets can just disspate a couple of Watts without melting - while EUC operation they have to disspate more something like 20-30 Watts, maybe even a bit more. The mosfet drain (pin 2) is mostly connected to the metal plate of the mosfet. Since in EUCs the mosfets are used for 3 H-Bridges (for the three motor coils) the drains of the "upper" mosfets are at battery voltage, the drains of the "lower" mosfets are connected to the corresponding motor coil. So different potentials and a massive short if not insulated from the heatsink. Even if all were at battery voltage one would want to insulate the 100V(84V,67.2V) from the heatsink....
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