Badzilla Posted August 13, 2017 Share Posted August 13, 2017 The hub motor is the heavy part? Followed by the battery? What is the lightest decent quality electric unicycle? It does not have to be fast. Strangely... My Airwheel Q3 260wh weighs about 26 pounds even though they say it weighs 30.2 pounds. My homemade electric bike ways 31.5 pounds which is only about 5 pounds heavier than the Airwheel Q3 (without seat and steering). When sitting down, a steering apparatus might be more important. Even if a steering bar is unnecessary, I want something in front as a slider to help with potential falls. My aluminum frame modified BMX bike uses a high-powered Dewalt cordless drill and is very reliable. I will need some weight savings to make the electric unicycle a practical alternative. But apparently current technology hub motors are heavy. I plan on adding a seat and lightweight steering apparatus that will increase the weight. Link to comment Share on other sites More sharing options...
sanman Posted August 13, 2017 Share Posted August 13, 2017 18 minutes ago, Badzilla said: What is the lightest decent quality electric unicycle? It does not have to be fast. You may want to take a look at the Solowheel Xtreme - it's light but not super-fast. This model is no longer available, but something similar is possible being sold under the Glide 3 name. Link to comment Share on other sites More sharing options...
Mono Posted August 13, 2017 Share Posted August 13, 2017 1 hour ago, Badzilla said: The hub motor is the heavy part? Followed by the battery? Yes. An the smaller the wheel, the smaller and lighter the motor. 1 hour ago, Badzilla said: What is the lightest decent quality electric unicycle? It does not have to be fast. Strangely... My Airwheel Q3 260wh weighs about 26 pounds even though they say it weighs 30.2 pounds. The Gotway MCM2s and the IPS Zero both weigh 11kg with 340Wh. Link to comment Share on other sites More sharing options...
electricpen Posted August 13, 2017 Share Posted August 13, 2017 The new Gotway Mten3 announced today is supposedly 10 kg and 512 Wh with an advertised top speed of 40 km/h. If it lives up to its specs it probably would take the top spot for small powerful wheels. Link to comment Share on other sites More sharing options...
Keith Posted August 14, 2017 Share Posted August 14, 2017 On 13/08/2017 at 1:31 AM, Badzilla said: But apparently current technology hub motors are heavy. And will be for the foreseeable future: to quote: https://www.thyssenkrupp.com/en/company/innovation/sustainable-mobility/electrical-steel.html Are powerful batteries the most important thing for electric motors in vehicles? Not quite; a very special material is needed to get the power from the battery onto the road: electrical steel. Electrical steel is a soft magnetic material. In such materials an external magnetic field generates a magnetic flux density that is many times higher than would be the case in air. In simple terms, the magnetic field is strengthened by the soft magnetic materials. Flux density is key to the torque of an electric motor. So you have large amounts of soft steel, copper and rare earth magnets and, as a result the power and torque the motor produces is pretty much proportional to its weight. A geared motor can run at higher kV I.e. Higher RPM for a given voltage and much higher current as it can, and will have less turns of much thicker copper wire so the motor can be physically smaller and lighter. However direct drive is much to be preferred on an EUC and possibly as much as half the power being produced is being consumed just to balance the rider, so the requirements for a bike type two wheeled vehicle are very different, the motor only has to run one way, doesn't need anywhere near as much power for the same acceleration and top speed unless it is a hell of a lot heavier. Given that the EUC's major weight is a direct drive motor and battery, lighter will and does mean less power and/or less range. Using exotic materials to save weight in the case etc. would give very little gain on such a minimal vehicle. Geared EUC motors have been tried (Fastwheel Orbit, Solowheel Ring, etc) questionable reliability and poorer resolution in balancing, resulting in a "loose" unpleasant feel for the rider made them undesirable. a ten inch wheel like the small Gotway would probably be the lightest around: but the smaller and lighter the wheel the LESS suitable it is going to be for adding "steering apparatus" (adding steering to a single wheel is something I have JUST got to see!) and a seat. Why not start by taking a look at the several designs that are already around and note that they are all much bigger than EUC's: Link to comment Share on other sites More sharing options...
Mono Posted August 14, 2017 Share Posted August 14, 2017 18 minutes ago, Keith said: However direct drive is much to be preferred on an EUC and possibly as much as half the power being produced is being consumed just to balance the rider, so the requirements for a bike type two wheeled vehicle are very different I don't think it is an unsurmountable task for a gearing though. 18 minutes ago, Keith said: Geared EUC motors have been tried (Fastwheel Orbit, Solowheel Ring, etc) questionable reliability and poorer resolution in balancing, resulting in a "loose" unpleasant feel for the rider made them undesirable. You seem to forget the only(?) one which was actually sold and used in notable numbers, i.e. Rockwheel? AFAIR the main problem of the Rockwheel seemed to be reliability and noise, not so much the performance in itself. I agree that geared wheels are a technological challenge that none of the brands in the market are willing or able to solve under the current market volume perspectives. Link to comment Share on other sites More sharing options...
kasenutty Posted August 14, 2017 Share Posted August 14, 2017 Got any pics of your Dewalt drill-powered bike? Link to comment Share on other sites More sharing options...
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