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  1. Username1

    Steel Rim as Magnet Backing?

    If you designed it from scratch, could a steel rim itself be used as the magnet back iron? I’m talking about a motorcycle type rim, and placing the magnets on the flat centre channel (facing the hub). Obviously the supports would need to be placed on the sides, not the centre. Is there any...
  2. Username1

    2x Speed = 8x Power?

    I’ve read that doubling your speed requires 8x the power, and I’m trying to understand why. Here’s my current understanding… Because the speed is doubled you’re encountering (slamming into) twice as many air molecules, which on its own requires 2x the power. Because the speed is doubled you’re...
  3. Username1

    CV Charging Sucks?

    In my opinion the standard charging method for l-ion should be CC instead of CC/CV. If you think I'm wrong please read this and tell me why because I must be missing something. Constant current (CC) gives a linear increase in charge over time. Once max voltage is reached, you end up with a...
  4. Username1

    External BMS?

    I was looking at "Chargery" chargers, and saw they also have BMS units that hook up to their charger. Does this mean it's possible to run an ebike battery without any BMS permanently hooked up to the battery? It seems all production ebike batteries use an internal BMS. Could you build your own...
  5. Username1

    PTC Battery Heater?

    I want to buy a Dualtron City scooter for year-round use in frigid Canada, so I'm investigating battery heating. The idea is to have the heating entirely powered by, and contained within the removable battery itself. This is because the battery is sealed whereas the compartment isn't (it has...
  6. Username1

    Heat Problems from Insulated Batteries?

    For people who don't live in hot climates, cold weather poses a big problem for batteries. One obvious solution is insulating the battery case and adding a heater for when it's cold out. My question is would heavy insulation ever be a problem in hot weather? The cells produce some heat of their...
  7. Username1

    Question About Thermodynamics

    This question came to mind when thinking about heated battery packs... Let's say you had extremely good insulation that let out virtually no heat. You also have a heating pad that heats up to 30°c. From what I understand you can never heat an object hotter than the source, meaning the battery...
  8. Username1

    Single Cell PEVs with Boost Converter?

    In theory would it be possible to run a PEV using a single large LFP cell with a boost converter? I'm talking all the way up to powerful PEVs like high-end escooters. For example using a single 1000 ah LFP cell (3200 wh). Let's say you used a fairly reasonable 2c discharge. That's around...
  9. Username1

    Ideal Household Electrical Standards?

    Disclaimer: This thread is purely for fun and autistic contemplating! I was thinking about home electrical, and what's best standard in theory if a country was starting from scratch, with similar power levels as today. Here's my idea (remember I'm no expert). What do you think, and let's hear...
  10. Username1

    Extension Cord Charging Questions

    I'm looking for some advice on EV charging with an extension cord.... The distance is over 75ft so I'll need a 100ft cord. I need to retract it after each use, so I want a flexible/light cord that I can wind up on a reel. For that reason I've decided that 30a power (24a charging) is sufficient...
  11. Username1

    How to measure battery temperature?

    I have decided to insulate my electric unicycle for winter riding, but I need to be able to check the temperature to see the affect. I don't want it getting too hot or cold. Can anyone recommend an easy way to monitor the temperature? Some kind of temperature sensor I can buy to slip inside the...
  12. Username1

    When will 4680 cells be available to the public?

    We saw Tesla develop the 2170 size, and shortly after other companies began making cells in that size, which we are now able to buy. I believe I've read that other companies will also be making 4680 cells at some point. When do you think we'll see these available to the pubic by companies like...
  13. Username1

    Thermal insulation for batteries?

    I'm going to buy a long range ewheel, and want to be able to ride it in winter for many hours at a time. It gets well below freezing here in the winter, so I'm looking for the best insulation to wrap the batteries with. I believe the best stuff you can buy is aerogel insulation, but it would...
  14. Username1

    Single Cell Battery

    A battery made of a single cell. For something like a car it would be physically impossible, but for a moderately powered ebike or escooter it actually does seem possible according to physics. No doubt it's not the most practical, and the cells/motors/controllers/chargers aren't currently being...
  15. Username1

    Unloaded vs Loaded Speed?

    I know that KV is the unloaded rpm/volt. But what about when you are riding? Does kv accurately represent your top speed when taking the wheel size into account? (dd hub motor) Or is the top speed actually less than the kv would suggest?
  16. Username1

    Low Power, High Regen?

    I'm considering to build an LTO (lithium titanate oxide) ebike using 40ah cells... Since the energy density kind of sucks, i want to keep the power low (around 20mph). But seeing as these cells can take a massive 10C (400a), i want to take advantage of regen braking. I don't mind using an...
  17. Username1

    Does acceleration affect range?

    So obviously your speed greatly affects range. But i was thinking, does your acceleration make much of a difference? Using high power to accelerate obviously draws more energy (per second), but the acceleration also ends faster. Then the opposite is true for low power acceleration. Assuming...
  18. Username1

    Questions about CC charging

    So i learned that a constant current method varies the voltage applied to the battery, in order to maintain a constant current. My question is what does constant current mean? Does this mean constant amps or constant watts? Also, regardless of the answer to the above question, why would you...
  19. Username1

    Charging LTO at Max Speed?

    I recently learned about LTO and and i'm really impressed with it, so much so i'm considering making my own battery... But my question is about the possibility of charging at full speed (10 minute at 6c). I didn't see any examples of people trying this, so i'm wondering is there anything...
  20. Username1

    Advice for homemade 13s8p pack? (low power)

    I want to build a bigger battery for my (stand up) escooter using 18650 cells. The power would be just 500w with 48v, so the purpose is longer range... I'm thinking of using 13s8p (104 cells). From what i understand, the higher capacity cells are around 3.4ah and must be used with low c rates...
  21. Username1

    Upgrading scooter from 36 to 48v?

    I have a 350w 36v scooter which goes about 25kph. I am planning to build a much bigger battery for longer range, but i would also like a little bit more speed. I'm thinking of increasing the volts to 48 (500w), which should give about 32kph i believe. Some questions about this... - Would i be...
  22. Username1

    Homopolar Switched Reluctance Motor

    I found this paper about an interesting type of motor. https://fdocuments.in/document/a-new-two-phase-homopolar-switched-reluctance-motor-for-electric-vehicle-applications.html They actually researched it specifically for electric vehicles like ebikes and escooters. It has some interesting...
  23. Username1

    Non self starting 1-phase induction motor?

    I know that a single phase induction motor uses an auxiliary winding 90 degrees apart to allow self starting... My question is, are there any examples of a 1 phase induction motor WITHOUT this? I just want to see what one looks like and study it. Searching online just revealed tons of info...
  24. Username1

    Motor with Electromagnets on Stator and Rotor?

    What if you had a normal BLDC DD hub motor, but instead of magnets on the rotor you had another set of electromagnets? To make this work you could have separate batteries spin with the rotor, so no cord would get twisted. I'm imagining an even number of poles on the stater and rotor, which line...
  25. Username1

    Single phase PM hub motor?

    Although I’m still very noob, I like researching and learning about different motor types and how they work... For example this image I found which I believe is a single phase PM out-runner. But I have a few questions... - Woundn’t this motor provide very high torque/power considering A...
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