Pros and Cons
Advantages:
- You can pedal while stopped and "bank" energy to be used while moving.
- Pedal at a steady output level regardless of speed.
- Capable of much higher speeds than unassisted (at least for a little while).
- The efficiency of electric motors generally increases as the RPMs go up.
- The efficiency of a standard derailer type drivetrain drops at higher speeds (approx 80% at 40 mph).
Disadvantages:
- Efficiency; you could build the system for not much more than a good derailer system, but the efficiency would probably only be 60% or so.
- Price; you could build a system with better efficiency than derailers ... for several thousand dollars.
- Weight; The best system you could build today would weigh at least 8 lbs more than a derailer system (not counting batteries).
A mid priced system is what I'm shooting for. Hopefully I can build a system with an overall efficiency of 80% or better, that costs less than $1000.
I'm also hoping to get the weight down to about 15 lbs (not counting batteries)
The batteries I currently using, Cyclon Monoblocs 60 volt pack, weight 31.5lbs. These batteries can produce 375 watts for 1 hour, that's more than anyone but an Elite Cyclist can produce, it's almost twice what I can produce and 3-4 times what the average cyclist can produce. Not bad for only 31.5 lbs.
I'm planning on switching to NiCads. A pack than can produce the same power as above will weigh less than 18lbs
