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  1. P

    10kW BLDC motor controller up to 90V and 200A with sensorless FOC - build thread

    I've been planning to start my controller thread for a long time, now here it is. It's about my latest build that I made for development and testing purpose, started sometime in the spring last year and still in progress. It was designed to fit in the hammond 1590U or the gainta G0474 box...
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    Motor built into the rim - student project

    A very interesting rim motor concept and prototype made by students at BME (Budapest University of Technology and Economics). Photos are here and below starting in 2014, and a video in Videos album: https://www.facebook.com/paradicsomcsapat/photos_stream (note, I'm not in contact with the guys...
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    Undrilled motorcycle rims?

    I'm planning buy 16 or 17" motorcycle rims and drill them for 14g and 12g spokes. Nipple hole diameters would be probably 4.5mm and 5.5mm, and should be drilled in the proper angle for a bicycle hub in the front wheel and a DD hub motor in the rear. But I did not find much choice of undrilled...
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    Theoretical lipo fire. What would happen...?

    Lithium is hazardous. We can apply proper charge-discharge procedures to prevent fire, but it is not 100% secure. What kind of protection is required to ensure that lithium fire will not endanger anything outside the battery pack that is built into a bike or other vehicle? Specifically I'm...
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    What are the best rear shock settings with hub motors?

    The hub motors are heavy, the unsprung weight of the rear wheel is much more than without a hub motor, so the proper suspension adjustment is not easy. But there are opinions that despite the extra weight it can be set properly and the weight is not a drawback. Today many offroad ebikes are...
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    Formula E championship starts today!

    This may be a historical event to change the future of car racing and for more people to recognize the world of electric vehicles. http://en.wikipedia.org/wiki/FIA_Formula_E_Championship If someone knows an online stream of the race, please share here. The official website is not accessible...
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    What do you think, Hesjedal rode an ebike on Vuelta Espana?

    https://www.youtube.com/watch?v=hIlmtQKLMUg After he falls, the rear wheel touches the ground so its rotation should stop or slow down, but after he removes his foot from the pedal the bike starts moving. At that moment the angular momentum of the wheel probably would not be enough to move the...
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    Effect of magnet weakening in BLDC motors?

    When the permanent magnets weaken due to overheating, does it increase KV? So it reduces torque and increases top speed? - I guess so, but I need opinion from motor experts. Magnets weaken gradually or suddenly at high temperature? Can there be any other change in a motor that is able to...
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    Measuring Cromotor v2 stator temperature without NTC

    This can be useful, if you have this motor and you don't want to open it to install an NTC. So, Cromotor v2 has a spare Hall-sensor set in the stator core close to the windings, that is normally unused. Between the output of the hall-sensor and the GND there is a reversed diode embedded inside...
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    Peter's custom bikes

    Hello people, let me show a few drawings of my next bike, any opinion is welcome. This is a shed project, building has been started. The frame will be one piece, the colors mean only that the orange parts are made of tubes and hollow sections, the yellow is sheet steel. The room for battery is...
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    Building a charger for 100V battery pack

    I need to design and build one to charge my 29s Lifepo4 pack. In fact it must be a switched-mode power supply (inverter) with regulated 106V output voltage and around 10A limited current (but variable voltage and current is a nice to have). My cell balancer is in the BMS, so only one high...
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    Lacing large hub motor in 24" bicycle rim

    Usually they are laced with 1 cross, but then the spokes are heavily bent that I don't really like, because it strains the holes of the rim sideways, so maybe radial lacing is better in this respect. I know Sheldon Brown's article in the topic ( http://sheldonbrown.com/wheelbuild.html#radial )...
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    Any heavy-duty twist throttle on the market?

    My chinese plastic throttle broke when I drove through some potholes. These throttles seem absolutely not safe, not only because they can break, but because the hall sensors in them are bipolar sensors. So when they break and both magnets are away from the sensor, they send 2.5V to the...
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    HT3525 Y-delta mod, stange hall sensor behavior

    After changing my motor from Y to delta, I experience some strange hall sensor signals: at first it seems the hall signals are delayed by 30 degrees due to the mod, so I added a half hall-tick delay in the firmware of my controller, and after it expires, the commutation switches in the next...
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    BLDC controller PWM switching method. Please help!

    I built my 12 FET BLDC controller for hub motor with IRFP4568 FETs, IR21844 gate drivers and an Atmel microcontroller. Now I'm playing with the firmware, and I have an issue with the PWM switching. I tried several methods, but none of them seems to be very good... I try to explain the problem...
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    BMS algorithm question

    I'm designing a BMS for 15Ah LiFePO4 cells with shunt resistor balancing, and it's not clear how the BMS should manage the balancing period around the end of charging. I have 2 options: 1. When the voltage of any cell reaches 3.65V, then apply its shunt and switch off the charge current. When...
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    Hello, I use a hub motor (HT3525) with 45V lifepo4 battery p

    Hello, I use a hub motor (HT3525) with 45V lifepo4 battery pack, and I have a problem: during downhill above 40..45 kph the back-emf is higher than the battery voltage, so the back-emf charges the battery with uncontrollable current through the controller's MOSFET freewheel diodes and the BMS...
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