This came about by a little 3kw golden motor arriving in the mail, from my big little brother.
We have been on the look out for a suitable high quality mid drive motor for high performance down hill type bikes in the 8-12kw region that weigh in under 5kg. To keep things simple we wanted to use single 219 chain reduction, so rpm can not be more than around 6000 so torque has to be up around 30Nm or so or around 250Nm at the tyre. Trying to buy something with this sort of torque density has been difficult. The CA120 with its high pole count and long stator teeth has excellent copper fill and has made 14 H.P on the dyno for only 2.2kg! But it is really pushed at that, and really needs double stage reduction which gets complicated and noisy at these sort of revs, and a very high speed controller for these high E rpm. The Pletenberg Nova 15 is very expensive for me to "tinker" with and is un proven, and have to use their controllers etc. The colossus motor had everyone vey excited until they tried to find a controller to cope with its very low inductance (I Don't know how Arlo is still sane after all his efforts). Although splinters old RG motorbike is up and going well. Miles's larger motor design show so much promise but do not exist out side FEMM :wink: . Toolman2 has just got his Joby JM1 going in his proper custom down hill bike and it rides real well. It is light 2.5kg ish , efficient, powerful, runs cool, but pulls 9000rpm so needs a double drop transmission so is a bit noisy up high. The motor is nice and open for cooling but a bit open to damage, this can be sorted fairly easy but is still a very expensive option.
We don't tend to link Kick scooters with performance. My brother in law, Pickle had a small mongoose brand scooter with 16" wheels and I had a spare 16" wheeled hub motor, 18 fet controller and 80 volt pack. So after a bit off welding to mount the 24S of a123's and electrical tape it was up and running. The small 16"wheels and high volts gave better acceleration off the line than my 8kw downhill bike! It was named Skootzilla and was always just leaning against the garage wall ready to step on and go for a very quick run to the shops or initiate ignorant non electric believers. It just felt like electric wheels for your feet. The small controller was quickly upgraded to a 24 fet controller and the long black wheel spin marks are still on the drive way a year later. Power drifting on damp grass at the oval was fantastic, if you could link a couple of 100 meter power drifts together it was really fun, and if it dug in and you high sided you just step off at speed with out being tangled in bike frame and pedals. But doing wheelies standing side saddle just feels wrong! I live on a yacht so with other yachties after a few sundowners we all looked forward to a bit of low tide speedway action on the hard sand. I decommissioned it after another broken rear wheel and we all sort of miss the silliness that was scootzilla.
This Golden Motors 3KW axial flux motor is not anything like the Joby or Plentenberg etc. You order one for $300 and it shows up that week. It has hall sensors installed, a low pole count so any of cheap controllers can run it at speed. It has a beefy steel shaft to mount a drive sprocket on instead of a aeroplane propeller mount. It is sealed up for daily dirty use/abuse. It comes with a small ineffectual looking fan or just tick the box for water cooling for a few extra US Peso's. It weighs in at a porky 7.4KG But if you got real serious and through away the motor housing and run the whole lot out in the open with a counter levered rotor etc you might get close to 5kg. I spun it up on 80volts with a little 18fet infinion controller and plotted the RPM verse no load losses at a few rpm points using a laser tach and cycle analyst with a external shunt. I will dig up and load the graph tomorrow .
View attachment 3kW 48V wind Golden Motors Axial Flux Motor tested at 80V.pdf
We have been on the look out for a suitable high quality mid drive motor for high performance down hill type bikes in the 8-12kw region that weigh in under 5kg. To keep things simple we wanted to use single 219 chain reduction, so rpm can not be more than around 6000 so torque has to be up around 30Nm or so or around 250Nm at the tyre. Trying to buy something with this sort of torque density has been difficult. The CA120 with its high pole count and long stator teeth has excellent copper fill and has made 14 H.P on the dyno for only 2.2kg! But it is really pushed at that, and really needs double stage reduction which gets complicated and noisy at these sort of revs, and a very high speed controller for these high E rpm. The Pletenberg Nova 15 is very expensive for me to "tinker" with and is un proven, and have to use their controllers etc. The colossus motor had everyone vey excited until they tried to find a controller to cope with its very low inductance (I Don't know how Arlo is still sane after all his efforts). Although splinters old RG motorbike is up and going well. Miles's larger motor design show so much promise but do not exist out side FEMM :wink: . Toolman2 has just got his Joby JM1 going in his proper custom down hill bike and it rides real well. It is light 2.5kg ish , efficient, powerful, runs cool, but pulls 9000rpm so needs a double drop transmission so is a bit noisy up high. The motor is nice and open for cooling but a bit open to damage, this can be sorted fairly easy but is still a very expensive option.
We don't tend to link Kick scooters with performance. My brother in law, Pickle had a small mongoose brand scooter with 16" wheels and I had a spare 16" wheeled hub motor, 18 fet controller and 80 volt pack. So after a bit off welding to mount the 24S of a123's and electrical tape it was up and running. The small 16"wheels and high volts gave better acceleration off the line than my 8kw downhill bike! It was named Skootzilla and was always just leaning against the garage wall ready to step on and go for a very quick run to the shops or initiate ignorant non electric believers. It just felt like electric wheels for your feet. The small controller was quickly upgraded to a 24 fet controller and the long black wheel spin marks are still on the drive way a year later. Power drifting on damp grass at the oval was fantastic, if you could link a couple of 100 meter power drifts together it was really fun, and if it dug in and you high sided you just step off at speed with out being tangled in bike frame and pedals. But doing wheelies standing side saddle just feels wrong! I live on a yacht so with other yachties after a few sundowners we all looked forward to a bit of low tide speedway action on the hard sand. I decommissioned it after another broken rear wheel and we all sort of miss the silliness that was scootzilla.
This Golden Motors 3KW axial flux motor is not anything like the Joby or Plentenberg etc. You order one for $300 and it shows up that week. It has hall sensors installed, a low pole count so any of cheap controllers can run it at speed. It has a beefy steel shaft to mount a drive sprocket on instead of a aeroplane propeller mount. It is sealed up for daily dirty use/abuse. It comes with a small ineffectual looking fan or just tick the box for water cooling for a few extra US Peso's. It weighs in at a porky 7.4KG But if you got real serious and through away the motor housing and run the whole lot out in the open with a counter levered rotor etc you might get close to 5kg. I spun it up on 80volts with a little 18fet infinion controller and plotted the RPM verse no load losses at a few rpm points using a laser tach and cycle analyst with a external shunt. I will dig up and load the graph tomorrow .
View attachment 3kW 48V wind Golden Motors Axial Flux Motor tested at 80V.pdf
