The life cycle of Lipo batteries is really dependant on how they are run. They can last 1,000 cycles or more if they are treated well (not too much current pulled from them and a decent amount of capacity left in the cells). Abuse wrecks Lipos. I have alot of experience with these cells. They will probably last far longer than I need them too. I will most likely get better cells before these wear out.
As for noise, these motors are super quiet. So, are the belt drives. My CNC is running a similar motor and belt drive. It makes sound, but nothing obtrusive.
Safety is always a concern. However, I have never seen anything let go on one of these motors. Their quality is extremely high. But, if you look at the power unit, the top 1/4 inch aluminum plate is just above the motor. That should protect my rump in the event of a motor failure! :wink:
I have no problem answering questions. I know this is a very unorthodox setup. I am sure very few people in the bike world are familiar with these components. So, it is all foreign to them. No problem. Plus, some of my assumtions and calculations could be wrong. I am open to that possibility.
The torque arm is a finuuy thing. A couple people have told me I won't need it. I will do some testing to find out.
With a larger rear sprocket, there will be less chain torque and therefore, less frame stress. The torque moves to other parts of the system (the rear hub). that is teh part I am worried about. But, I will go to a better wheel and hub if need be.
My CNC is a Taig brand. My manual mill is a Taig also with a 5 axis trunion table. The trunios pivots are made by High Tech Products and the two required rotary tables are made by Sherline. These machines are small and a bit crude, but they work very well. I am 100% self taught. It can be done.
Oh, a comment was made responding to my comment about the 7075 aluminu sprocket being hard to machine. Generally softer aluminum is tougher to machine than hard aluminum. But, that is only true to a point. Once you reach 6061, it begins to get harder to machine. 7075 is the hardest aluminum that I have ever found. It is tough as nails! Actually, I think a nail would be far easier to machine. Plus the sprocket is anodized which adds to the toughness. I asked a couple full time machinists about this and they confirmed this. 7075 is really hard to machine. But, it is phenominal stuff!
I am hopefull everything will be OK. But, there are many things that can go wrong with a project like this. I have been blessed with good luck, so to speak with my one-off projects. I have built many custom heliscopters, RC cars, car audio setups, etc and everything I have ever designed and built has worked and normally without any glitches. I do not mean to sound arrogent, but my mechanical problem solving during the design phaze is super high. I just wish I had better equipment and more money to make more cool projects happen. The design and marriage of many components into one seamless whole is what I enjoy most. But, this is my first E-bike project. It could very well have some serious problems.
Matt
