Recent content by mike_o

Thanks for the inputs! Sounds like I could start out with plywood and if the thing is a success and the plywood proves to weak, it could be upgraded to fibreglass. Or inforced with it.

I'm considering building a lightweight, low power ( 2 x 3 KW) kart-like vehicle. Gokart wheels, independent rear drive shafts, dual belt drive BL motors and dual ESCs with steering vectored "electronic diff". Each motor drive, shaft, brake and wheel bearing mounted in identical stiff...

markz, sorry for the delay. I'm about 210lbs and the weight added by motor/drive/ESC/battery is very low, like 4lbs.

A little update: Currently running the bike with an 4258mm NTM 500KV motor on a single 6S pack (the 3 x 3S packs were just too troublesome to charge - one at the time).With a 16T sprocket the gearing is something like 16:780 or 1:48. I have enlarged the tensioner bearings for lower friction and...

I'm using a VESC on a low power belt drive MTB (https://endless-sphere.com/forums/viewtopic.php?f=3&t=97578&p=1434140#p1434140). I've tried 3 or 4 different motors and voltages ranging from 4S to 9S. And I've also tried switching between FOC mode and the normal "PWM" mode. In all cases I've...

My VESC is equally cool in both modes. I can't really feel any temperature increase. I'm afraid that I don't have access to an oscilloscope that can sit on the bike while driving...

Thanks - Actually I have just replaced it with a metal pull spring :)

On FOC efficiency: After having run different motors in different modes (FOC/"BLDC") and configurations, it seems that the motors always run at a higher temperature and with lower efficiency in FOC mode. I may be loosing up to 20% range in FOC mode. I wonder why? Maybe because I'm running the...

The 25T brass pulley arrived after quite some shipping time. Meanwhile, some othe stuff also arrived, including 5 pcs of new 1524mm GT2 belts and a 280kv 5055mm SK3 motor: It was on sale ($30) at HK, so I grabbed one to get the current down (low KW = equals more cells = lower current), as my...

I passed the 100km mark today, and celebrated by replacing the 20T pulley with a fresh 16T Alu pulley (the only one available with the brass pulley sitting in a slow boat somewhere). I also swapped the 4240mm 650KV motor with a 4258 mm 500kv and went from 4 to 6S. The 10mm GT2 belt looks rather...

Pulley wear at 70km: Still no slippage, but it doesn't look like it will make it past 100km. Waiting for the brass pulley to arrive. I wonder what causes the wear: Just the fibre inforced belt, or dirt particles picked up from the non-slip surface or from the street? 3M or 5M belt and...

hahaha :thumb: Back to topic: I couldn't muster that kind of enthusiam for a rusty bike unless it was very, very special. And did you consider the effect of galvanic corrosion when bolting together steel and aluminum? Put those two metals together, add salt water, and the aluminum will wither...

I've done 60km so far. The belt looks nice and there is no slipping whatsoever, but the 20T alu motor pulley shows sign of wear. It has rotated 900.000 times now, so thats perhaps to expect. I have ordered a 25t brass pulley to better cope, but going 5mm module belt is probably a better solution.

My current tensioner does not allow braking. It will only make the belt slip on the motor pulley. To overcome this, I'm designing a dual way tensioner: and brake mode:

1mm wire through dual holes around the spokes. In 8 spoke positions I cut small recesses as half of the spokes are outside/higher than the other 8. This way, the rim/ring rests nicely on 16 spokes. I don't expect to transfer monster power this way, but it seems to cope effortlessly with the...