Hi all, I'm new to the forum, but I've been doing heaps of reading and am looking to build my first proper ebike
I've followed kepler's super commuter build (https://endless-sphere.com/forums/viewto ... =6&t=47139
) and am keen to follow the same basic philosophy, but with slightly higher speed potential, but still the same level of stealth (well a bit less, I will be running 2 hubs after all)
I'm aiming for a top speed of around 70kph (45ish mph), and am hoping to achieve this with 2 small bafang motors, an SWXH on rear hub, SWXK5 for front, oil filled and running at 1000 watt each, achieved through a 24s lipo battery pack (probably 4 6s in series) running at 96 volt.
This means each motor will only need a max of about 11 amp through them, and I'm fairly confident that with the oil they should be able to take this, using a CA3 to control max watts/current and overheating. I also have an electrical background so modifying the controllers to be 100V capable shouldn't be too much of an issue.
Looking at the bike calculator (http://bikecalculator.com/veloMetric.html
) I will need 2000 watts of power to reach 70kph, which works out well for the 2 motors.
The motors themselves are also internally identical, with different cases for front/rear use. Both come in a 201 rpm @ 36 volt winding, which at 96 volts gives me
201 / 36 x 96 = 536 rpm
536 x 2200mm wheel circ = 1,179,200mm/Min or 1.1792km/Min
So this also works out well with the 2000 watt at 70 kph figure from the calculator. It's also with a fairly median sized wheel circumference, so I can change that around to move free wheel speed up or down.
General cruising speed would likely be around 40 kph.
The issue I'm facing is that I can't use the simulator because there is no way for me to do a 2wd simulation, and the closest motor on there is the cute q100 with a high speed winding, so I'm not sure how the heavy bafang and high torque winding will fare facing 96 volt, 10.5 amp.
I'm also not sure how required rear suspension will be on this setup, front is a definite. Battery and controllers would be quite light as amp requirements are not high, nor is range, but I would be worried about damaging them without the extra shock absorption of rear suspension. I'm also worried about control-ability at top speed without the rear damper, let alone not being shaken to pieces.
I'm also assuming wheel spin shouldn't be an issue because I'm using quite small motors, but again I haven't used these before
Any input would be much appreciated!
UPDATE: Motor candidates have been changed to the one in https://endless-sphere.com/forums/viewto ... 30&t=53939
Its a slightly faster wind,70kph correlates with a 66v pack, if the Kv on that thread is correct.
The motor also has a larger gear reduction, not to mention coming half oil filled from factory so the bearings are likely already sealed so a complete fill for better cooling should be far easier!