voicecoils
1 MW
This build is essentially complete now. I'm updating this first post for the benefit of those coming to the thread and starting at the top.
Before:
View attachment 1
After:
The Plan: Take one of my current bikes and transform it into a nimble mountain climbing goat!
The bike: Full cromo frame including the front fork. Disc tab on the back, recently powder coated. Sun Ringle rims front & rear. The rear is laced to an 8speed Shimano Alfine internal gear hub, operated by a twist shifter.
Parts list
Motor: Banfang PMGR (from ecrazyman@gmail.com)
Controller: Analog Crystalyte 24-72v 35A
Throttle: Crystalyte half twist grip
Charger: 900W 72v10A from http://www.BMSBattery.com
Front Rack: CETMA 5 rail. Somewhere to put the groceries...http://www.cetmacargo.com (not on my bike at this moment)
Batteries: 24s1p pack of 3.3v, 10ah cylindrical cells (Headway packs from http://www.e-mtb.com.au)
Spokes: Cheapies from ebay 216mm for a 1-cross on a 26" rim. I'd suggest 214mm though.
Rear Hub: Shimano Alfine 8-speed, silver with splined disk brake rotor
Gear Ratio: 48 tooth front sprocket 16 tooth rear sprocket ~78 gear inches when hub is in direct gear (4th, 1:1)
Rim: Rynolite 26"
Monitoring: direct plug-in Cycle Analyst on the bike, stand alone used for monitoring charging
Battery box: Care of the EngineWisperer (http://www.enginewhisperer.com)
Performance:
Preface:The Bafang must be pedal-assisted to avoid overheating or thermal meltdown. It screams and acceleration is mild if you twist the throttle from a dead stop or hill with no pedalling. The Bafang cannot handle high current without rising in temperature rapidly. At 72v nominal, 12-14A seems safe and 18A seems like flirting with the devil (but is lots of fun!). Even limited to 9A, the assistance is quite useful. Pedalling the same bike with no assistance is a great reminder of how much work the motor does. I'm running 2 plastic gears and 1 metal gear. I've killed some gears and melted some hall sensors out of their slots in the motor but I haven't killed the motor.
Details
At 72v14A I can climb at 35 km/h, cruise at 45 km/h and descend at 55 km/h. (all with pedaling)
The no load speed is around 60 km/h.
Efficiency:
To be updated soon.
Before:
View attachment 1
After:
The Plan: Take one of my current bikes and transform it into a nimble mountain climbing goat!
The bike: Full cromo frame including the front fork. Disc tab on the back, recently powder coated. Sun Ringle rims front & rear. The rear is laced to an 8speed Shimano Alfine internal gear hub, operated by a twist shifter.
Parts list
Motor: Banfang PMGR (from ecrazyman@gmail.com)
Controller: Analog Crystalyte 24-72v 35A
Throttle: Crystalyte half twist grip
Charger: 900W 72v10A from http://www.BMSBattery.com
Front Rack: CETMA 5 rail. Somewhere to put the groceries...http://www.cetmacargo.com (not on my bike at this moment)
Batteries: 24s1p pack of 3.3v, 10ah cylindrical cells (Headway packs from http://www.e-mtb.com.au)
Spokes: Cheapies from ebay 216mm for a 1-cross on a 26" rim. I'd suggest 214mm though.
Rear Hub: Shimano Alfine 8-speed, silver with splined disk brake rotor
Gear Ratio: 48 tooth front sprocket 16 tooth rear sprocket ~78 gear inches when hub is in direct gear (4th, 1:1)
Rim: Rynolite 26"
Monitoring: direct plug-in Cycle Analyst on the bike, stand alone used for monitoring charging
Battery box: Care of the EngineWisperer (http://www.enginewhisperer.com)
Performance:
Preface:The Bafang must be pedal-assisted to avoid overheating or thermal meltdown. It screams and acceleration is mild if you twist the throttle from a dead stop or hill with no pedalling. The Bafang cannot handle high current without rising in temperature rapidly. At 72v nominal, 12-14A seems safe and 18A seems like flirting with the devil (but is lots of fun!). Even limited to 9A, the assistance is quite useful. Pedalling the same bike with no assistance is a great reminder of how much work the motor does. I'm running 2 plastic gears and 1 metal gear. I've killed some gears and melted some hall sensors out of their slots in the motor but I haven't killed the motor.
Details
At 72v14A I can climb at 35 km/h, cruise at 45 km/h and descend at 55 km/h. (all with pedaling)
The no load speed is around 60 km/h.
Efficiency:
To be updated soon.