I've been watching the giant RC motor thread with great interest over time. First off I must say that I'm all for making a forum division for this kind of stuff! Excellent idea.
Anyway I had the idea of using RC brushless motors for my e-bike project quite a while ago when the idea was still in initial brainstorming stage. Research pointed me eventually to Matt's E-cumbent and I was floored. Ever since then I've been slowly conjuring up my own design. I switched between gear drives, belt drives, different motors, different controllers, mounting methods, batteries... etc. But I've stuck with the design I have in my head right now for at least a few weeks, and I'm just about at the point where my funds are sufficient to get my hands dirty.
I'm planning to convert my Mongoose DX bike to a commuter e-bike. I have access to a small shop here at my university so I hope fabrication will not be too difficult. Here is the crude spec list in my head:
-TowerPro 5330-10T brushless motor (here
-Castle Creations HV85 ESC
-LifeBatt LiFePO4 10AH 12s1p (actually 6s1p x 2 so I can charge as a 6-cell pack with my RC charger)
-2 stage belt drive reduction (16/72) x (16/36) = 10.1:1 ratio (not for sure on the sizes), parts from sdp-si.com
-BMX freewheel on drive output shaft to sprocket mounted on rear disc brake hub (sprocket from this guy
I think that covers the basics. I chose the TowerPro motor because of its price, even though it seems to be well tested and checks out OK. I was originally going to go for one of the HexTronik or Turnigy motors (63-74) but it was very difficult to find information on them. Also, the protrusion of the shaft from both ends on the TowerPro will make mounting much easier I think. I'm planning on putting a small fan on the shaft to keep the motor cool like Matt did.
I hear Castle Creations is second to none in quality. Nobody else makes a high quality HV RC controller for that price either. As for the batteries... well, my university is competing in the Formula Hybrid competition again this year (check it out!
) and we're planning to use a giant array of these batteries in our design. When we make our order in the coming months, I'll tack mine on as well for the volume discount.
Some of my concerns right now include how I will fabricate and mount the housing. I am thinking I'll end up just cutting two aluminum plates with slotted holes. The shafts and pulleys will mount to backing plates with bearings that will be adjustable to keep belts tensioned properly. I need to sit down and draw this out in Inventor when I have the time. My other concerns include weatherproofing and keeping the batteries functional during Chicago winters (less than -10C). But I will have time to work that out.
Let me know if you guys have any suggestions or comments. I would love to hear some input. I plan on keeping a detailed record of the build once it gets under way. Thank you all for running so far with this idea, I have learned a lot from here!
P.S. Maybe I could get my old thread
I started back in May moved to here?