neptronix wrote: ↑
May 08, 2018 4:26 pm
I contacted them on alibaba and they only offered me a winding that does 28kmh ( 17mph ) for a 700c wheel. No mention of the 12.25:1 version. I had to refer to this thread to find that out.
I have a nice roadbike with drop bars and can hit 27mph on a flat pedaling sans motor if there's a slight grade or a tailwind, so i think the 12.25:1 ratio version would be more appropriate for a constant mild boost with PAS. I'm going to keep the phase amp to battery ratio extra gimpy ( maybe 2:1 or less ) so that it only gives me ~100w of boost from a stall and forces me to shift and pedal hard to get up to speed until the midrange kicks in and the wattage climbs to 200, 300, and peak at 350w, as that's what the efficiency curve tells us is the sweet spot for this motor
This motor will give WAY more power with the higher reduction ratio on 48v+, but i'm just looking for lightness and the simplicity of running a tiny 10S battery and the lightest hub that money can buy.
Weird. I am not sure if the winding changes in the different ranges. My understanding was that the gear ratios changed. Maybe if you tell them that it's going in a 20 inch wheel, they'll offer you the 12.25:1 ratio motor. You may have to run the motor at 15A to get any real off-the-line pull with that lower gearing and a 700c wheel though, and I don't know how well the motor will handle that many amps. I'm still running my motor at 12A which is OK for my typical riding conditions and the 17.5:1 gearing.